New ESP32 hardware design tutorial coming soon! Some comments: 1) I'd strongly recommend using off-the-shelf, pre-certified modules unless you have a very good reason not to. This video is more of a 'fun demonstration', rather than something that should be used practically. 2) Although I haven't had issues so far, the chip-enable cap (C19) value should be increased for reliability (as otherwise the default bootmode and chip enable come up at the same time on power on). 3) The antenna matching network and antenna itself will need to be tuned on the real PCB. These are just ballpark values. 4) There is a variant of the C3 (C3FN4) which contains built-in 4MB flash. Meaning you don't need external flash - however, these SPI pins on the C3FN4 cannot be used. Additionally, I believe the C3FN4 is NRND.
Thanks so much for putting this video back up Phil. Me and the rest of the beginner ESP32 designer guys really appreciate it. Why'd you put it back up btw? Also, for any of you guys reading this, you can just use the ESP32-C3FH4X, ESP8685H4, or upcoming ESP8686 for your new designs as they are either active or about to be released.
Thanks for the video. I was debating on either making the antenna design in the PCB or just get the card with the prebuilt antenna. After review of the price, i think its work the extra 50 cents. Unless I somehow sell 100,000 units lol.
I'm working on a design for the esp32-s3 so which includes 4mb flash and 2mb SRAM. My big question is why have the curve in the strip line... If board layout allows, is it permissible for the strip line to be a straight to the antenna feed point (with the PI network added of course)
Once again, Phil has come to the rescue by making a video of exactly what I need, as if by telepathy. This is the 2nd time this has happened and that’s strange.
Glad to hear the videos are helpful - it's a sorry state of affairs when it's this way round though :(
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@@PhilsLab The course was very theory-heavy. We never got to actually design a PCB, build it and bring it up. Thanks to your videos, I'm more confident now designing my own PCBs.
i need to say that you are the best embedded systems channel on youtube by far. watching your videos motivate me to learn more and more and tbh comparing myself to last year i've improved a lot in pcb designs and it's thanks to your videos and robert feranec's. hope you continue this quality containt and thanks for the efforts.
I just want to thank you for your free videos that you release on these topics. It has led me to discover what I want to study in college end goninto as a career. Thanks Phil
I have just discovered your channel today and have been watching several of your videos on KiCad and I have picked up a wealth of information, I happen to be in my mid-seventies, a retired electronics design engineer, very much into RF design, and this old dog is still learning new tricks. Well done, Mate! Looking forward to watching more of your Great instructional videos .
Aww. As someone who’s 25, I always worried that I won’t be able to do as much or learn as much when I’m older because I’m already so much slower than I was since I was a teenager, glad to know that you can still do cool stuff when you age !
I was looking for antenna design for esp all over the internet, but all of them were difficult and I lost hope. Now I got your notification, let's see.
As a rookie PCB designer, I am always in awe of what you do taking us to the design considerations used to produce boards that we buy off the shelf. I have no intention of reproducing this particular design (obviously above my paygrade) but I enjoyed watching the detail description of this author. Thank you very much professor Phil.
Ironically as it may sound, I was trying to design a depth measure system using the same MCU and a ToF but I found myself with difficulties specially designing the antenna part. So thank you once again Phil, for the wonderful surprises, and help you've been giving me. Waiting for your new course.
Literally the exact video I needed. Don’t forget the strapping pins when developing the board. I forgot to pull in of them high when I was designing the board and it caused it to fail when programming. Once I added a trace to 3v3 it all worked again
wow, this is exactly what I have been looking for, the TH-cam algorithm nailed me with this one. Just throwing it out there, but I'd also be really interested in a guide for how to use ceramic antennas in designs
Phil, congratulations for making such exquisitely detailed videos. You expound every detail, offer practical advice and support for your growing community of subscribers.
Wow I've been working on a bare ESP32 project and have been stuck on the antenna part for a while. This video just comes 2 weeks after, amazing thank you so much!
Few suggestions: you can use layer 3 or 4 as your ground reference to widen the microstrip trace so the lumped element component pads do not disturb the line width; it's worthwhile to utilize the top layer ground plane, e.g. the grounds of the antenna matching elements can be connected on the top layer for shortest length (inductance) instead of relying on interconnection through vias, the PIFA antenna ground feed should connect to the top layer ground plane, frequently spaced vias connecting the top layer ground plane to the rest of the the ground layers is important; the TI application note PIFA antenna dimensions are for a 1mm FR4 dielectric, it looks like your total dielectric thickness is 1.5mm FR4? This will change the loading on the antenna and require a shorter copper length resonator.
THANK YOU FOR THIS!!!!!!!!!!!!!!!!!!!! I am designing my own ESP32 based board and didnt want to do what everyone else does and just solder on a single ESP32 pre-built board (the one with the wifi antenea and such, not the full dev board, tho i've seen that too).... I am wanting to use the SOC direct and then design my own firmware and setup for it... and the ESP32-S3 is STUPID cheap and so simple!!! I just am getting hung up on the design of the memory and flash and such... I think i'll do an SD card for the flash part... but playing around with options... I am doing an external antenea plug in on the board since it will be in a case and wanted to have the full range available. But this helps out so much! i've been looking at recommendations from other sites and reading all the SOC documentation inside and out and printed it all out and marking my notes... This is by far the biggest custom PCB project i've taken on for my own little things... I normally would do the ESP32 and solder the wifi pre-made package board on it. But I wanted something more "professional". Learning to design and build PCB's self taught can be pretty steep learning curve. Only my Electrical Engineering classes in highschool from the late 90's is what I have education wise and all self taught componant diagnosis and repair and small self designed PCBs. But NO ONE has an SOC totorial for me to go through and verify my design and deployment based off the technical and design documentation from espressif direct.
Your video is great and saved me from making a critical error. I read the docs and didn't see anything about the LNA_IN output impedance (35 + j10) so assumed it was 50 ohm since that's the "standard". Turns out its not listed in the datasheets but is mentioned on the hardware forum.
Very detailed video about the whole steps that is essential to create an excellent PCB! But I have one suggestion for improvement that you can comment on: It's necessary for PCB antennas to open solder mask above them. Solder mask dielectric constant can dramatically change the characteristics of the created antenna, because it is located in the path of radio waves propagation.
@@RSP13maybe - but the antenna / unit would probably be used indoors - so you wouldn’t necessarily have to worry about corrosion. If outdoors then one would assume it’d be housed in suitable enclosure. Outdoor antennas are constructed in aluminium - & some say not to clean them as the effects of environment on the surface of the antenna can improve performance!
As others previous replies - thank you for the step through of the design & great video. I only chanced on this video by googling the chip reference / & interest on the antenna design. With your simplified approach using what’s been done before & reference to the paper is very practicable too. I’ll be off to read that now. I saw another TH-cam where the antenna is printed on both sides so that’ll have some new techniques/benefits one presumes. Atb
Great video! I've been working with ESP boards for years now (developing ESPEasy) and I alway wondered what made one board work great with WiFi and why it worked so bad on others. I really would like to know how the WiFi quality is of this board, compared to other boards when running the same kind of scan at the same location in your house. Maybe also nice to check running some AP on various channels to see whether you hit the perfect center frequency and what the actual bandwidth/range is of your PCB antenna. Perhaps let some ESP board run a few meters away, starting AP mode on the next channel every minute and let your board (and others) scan and compare the RSSI values. Still this will of course also include some offsets caused by the "bad" antenna of the other ESP board acting as an AP. So maybe you could also test using a real access point and test on channels 1, 6 and 11 to cover the entire 2.4 GHz spectrum. Also really nice to see those ESP32-C3 are so easy to wire and program due to their internal USB interface. Meaning I really should start supporting the C3 also in ESPEasy :)
Hi Phil, Nice video overall. It was refreshing to hear you admit that there were going to be many external factors that will impact the overall tuning of the onboard antenna. A very realistic approach since the end user can put the board into a completely unknown environment with various other nearby metalic elements which will all impact upon the tuning and performance of the antenna. It was amusing to then see you worry about the PI matching network to match the 35j10 to the 50 ohms (nominal) IFA impedance. If by some chance your antenna ends up at 50 ohms (unlikely in the real world) without any actual verification / trimming then the power loss from the resulting mismatch is still pretty much negligible. All made more novel by the "close enough" values of the PI elements ;-) I realise the whole point is to demonstrate a complete RF path from the chip to the antenna and you did that well. Some people go to extraordinary lengths to try and get the match of some onboard antenna and matching network perfect whilst ignoring the reality that it will only ever be "right" at that moment in time on their bench lol. Just one more thing, in your layout you had the PI matching network inductor close and parallel to (I think) one of the RF power rail inductors. Personally I'd seperate those or put them at right angles to reduce any possible coupling but it again may make no practical difference! I'm not going to touch the whole solder mask or not issue in the RF path. All the best.
Thank you! I thought to make custom esp32 board with pcb antenna and after research came up with similar guidelines. But did not make it yet ... :) Now I will have more confidence that this thing will work, can't wait for your next videos!
Thanks for the video, it is really informative and I am glad that the content is of such a high quality! I had a couple of questions though. First of all, could you have just connected the antenna ground pin to the GND plane on the top layer. Of course adding a via to GND is also a neccessity there, but it seems against any logic not directly grounding that pin to the top layer of the ground. I checked some designs online and I see this being grounded to the top (if the top pour is GND that is). So potentially did you manage to find some information that was against doing this? Another questions is that I see people adding a picket-fence around the antenna feed line and the antenna itself, which should reduce stray signals from antenna entering the PCB and the opposite. I thought it is quite essential, but you seem to have managed to make it work without adding one. I wonder how would that affect the SNR overall.
Awesome video Phil, an absolute joy to watch and learn. Was looking into antennas in general and wanting to learn. This would be a great start! Thanks again!
@@PhilsLab You know how you can add comments within the code you write, is there a similar thing with Altium or any designer? Watching you explain diff sections of the schematic, I imagine having comments show up in a window on the side would be great. How do teams work together to design stuff?
Video is gold, I´ve seen extremely few people going over so much detail and the correct reason behind it over the years. And yes, technically you are being a bit naughty with the USB. As per IF-standard you should not draw more than 100mA continuously before enumeration, that being said, you would probably still be fine, if the first thing that you try to do when the device connects is to try to enumerate before activating the RF section. I do not know the C3 specifications, but I would guess, if you really wanted to turn this into a product with the USB-IF approved logo on the outside, it should not be a problem. But rumor has it, they turn a blind eye with a lot of products anyhow.
I manufactured an ESP32-S2 board and the impedance I got on the RF input was very different from the one on the datasheet ( 11 + 1j vs 31 + 1j ). This means the impedance matching network I designed actually reflected 95% of the signal at the 2.4Ghz carrier frequency, it actually worsened the problem instead of improving it, as removing the network and using a 0 Ohm resistor only reflected 50% of the signal. I have to say my stackup was completely different too from the one recommended in the datasheet. It might be worth to mention to ALWAYS leave an u.FL connector on the board to hook up a vector analyzer in case it doesn't work properly (and it will not if you make even a slight change on the stackup)
I might mention, the change I did to the stackup was using 0.8mm thick 2 layer board instead of 1.6mm thick 4 layer board. It also changed the impedance of the PCB antenna from 50 + 0j Ohms to 30 + 0j Ohms. Luckily I left an u.FL connector in place to know this information, and also pads to solder a Pi Network on the antenna end
Sir, could you tell me in what position did you place the U.FL connector? Was it between the ESP pin and the matching network or between the matching network and the PCB antenna? Thanks.
Very good! It’s a reminder if you depart from what has been tried / tested & used you might fall foul on the required design. Ok with a matching network to suit. Interested to know how you measured the above.
This is amazing. I learned so much. I made a pcb a couple of weeks ago and I thought I did quite well but I now know there are so many small mistakes in it after seeing this video haha. It might be fun to do a video about my pcb and point good/bad things out along the way.
@@PhilsLab hi thank you for your reply. I have sent my design in via the link you gave me. If there are any questions please let me know. I hope my design is not too bad 😬
You haven't explained the 35+j10R term yet. When I look at the ESP32 Drvboard V1 I see this PCB antenna directly connected without a matching network, because nominally the pin 1 is designed for 50 Ω and the devboard doesn't use any more matching.
I guess you could try and control the CC lines through the ESP32 directly, but it's far easier to use a dedicated USB C PD IC, which interfaces to ESP32 via I2C, for example.
You'll have to add in control circuitry + FETs as well in any/most cases, so I'd definitely just go with a dedicated controller that has the right gate drivers, etc. as well.
Thank you so much for making this video. It gives me alot of insight of making pcb board with MCU, i am wondering you like to add CLC pi filter to the power supply and analog supply, any tips for this kind of filter? For eg how to select the right value of the components. Thank you!
Very nice, I was designing esp32 data logger some time ago, and I remember including "reset" circuit connected to the external IC USB to UART and that had Data Terminal Ready and Ready to Send control output connected through two transistors to the EN and BOOT pin on ESP32, that helped with the reset after sketch upload. I wonder if this can be implemented in the SOC when the UART chip is "build in"
After this being the somewhat twenty-x-ish video of Phil I watched, I realised I have not yet subscrided to this channel, which I "fixed" immediately. I would love to hear and see even more about design considerations for EMI/SI ,because at least to me it appears that most people (including me) have still a lot to learn in this field.
Just for anyone watching, there is a version of C3 with built in flash as well (C3FN4, C3FH4, 4MB flash). I've used it on my own board and I thought that meant the SPI pins could be used for other things then but appears that the internal flash is connected to the same pins as they would for external. (yes I know it's stated in the datasheet that these pins are not recommended for other use, but I thought that was fi external flash was used). So good to know so you don't do the same mistake as me. :).
Thanks for the informative video. Is there any guidance on these ground planes on the top layer? Why some designs have them, but others don’t? When holes are required? Why there are some uncovered blanks spots?
For me the in between here is the Espressif modules. Not dev boards, the modules. They come with the flash already setup under the can and ... quite importanly an FEC Certificate of compliance. The chips on the other hand do not come pre-certified so any product that wants to carry the logo and get an ID has to go through it's own certification, submit it's own test/lab results etc.
This content is worth a lot, I struggle to find books and Udemy courses that will teach me more about embedded systems on this level. Please consider turning some of your work into Udemy courses in future.Thank you.
Phil i ove your videos. so clear, clean, ogranized and amazing in general. so informative. please do one with standalon bluetooth audio SOC. I will forever be grateful.
Hi Phil, Thanks for the video! Your content is more detailed than most videos I find on TH-cam. I am designing a board based on the ESP32. The documentation says that to ensure the power supply to the ESP32-S3 chip is stable during power-up, it is advised to add an RC delay circuit at the EN pin. The recommended settings for the RC delay circuit are usually R = 10 kΩ and C = 1 µF. However, I am not able to find the rise time anywhere in the documentation to calculate the correct values for R and C. how can i find those values
Hi Phil! Great resource to have as I am trying to use the bare ESP32 chip instead of a pre-made module. Could you please shed some more light on the Q24FA20H0020900 crystal you have selected here and how you derived the load capacitors at the 10pF level? Is the stray capacitance something you measured yourself? The datasheet for this crystal is not clear at all...... Thanks
Hi Matthieu, Thanks! As a rule of thumb, stray capacitance Cs is 2 to 5pF (due to PCB pads, routing, ...). You'll need to get the load capacitance of the crystal from the datasheet (e.g. Cl=9pF). Then to work out the value of the load capacitors, simply use CLOAD=2*(Cl-Cs). A ballpark value is fine (due to not knowing the stray capacitance exactly).
Thank you so much for making this great, educational video. With the implementation of the PCB antenna and matching network, how do you know if the design achieved a low SWR? Is there any practical way of measuring it?
Very nice! Thanks for the video - I enjoyed it as usual. By the way, you should change your wifi access point off of channel 6. According to your new scanner that band looks quite congested :)
Is there a reason you did not use the ESP32-C3FN4/H4? These do include integrated flash while the default version does not. And thank you so much for this video. This is beyond helpful. I have recently made a design with this chip and it was quite the learning experience to create my own non-module ESP32 PCB. I couldn't believe JTAG was built-into the chip. Cheers!
No particular reason other than showing how an external flash chip would be integrated. The FN4 design is definitely simpler/smaller with a similar cost. Glad to hear the videos have been helpful, thanks for watching!
Wow, really cool. First of all, your video with the ESC FOC controller helped me, because I was experimenting with BLDCs at that time and now this year I wanted to start a project with an esp32. Thanks for that. Will there be another video about the ESC and the FOC? Many greetings Michael. The content on your channel is great and so helpful.
Thanks, Micha. Glad to hear the videos have been helpful. Yes, I'd like to make a follow up vid to the ESC design, however, I have many projects ongoing at once, so it can take a bit of time I''m afraid.
I'm a beginner doing electronic boards and try about five times to make a functional ESP32 custom board using a lipo battery and I failed in all tries. I will try to do a new board again using your example. Wish me luck.
I have found SimSmith (free JAVA-based software) excellent for designing various matching networks. Of course, a basic understanding of Smith Charts is needed but the program will choose "standard" values for the various network types you want to implement and give you a pretty good Smith Chart representation of how it should react (also Bode plots).
Something that I would like to know is how do you define the parameters when you order it. Obviously, impedance control is a thing, but what other specific parameters are needed to order it?
Amazing video again 😍 Hope yo do same video for a GPS module Because i have to put components on the pcb with its antenna but i didn't find much resources
Great tutorial. Just one question. Why you don't choose the ESP32-C3FH4 version which include 4Mb Flash memory ?. Is there any downside to this choice ?
Thanks! To be honest, I can't remember why I chose this one - maybe to show how to hook up an external flash? In any case, as you say, the *FH4 version is simpler to integrate with.
Great video again Phil, love it. I downloaded STM32CubeMX and have been working through the tutorials. The software sounds awesome. I usually use Studio code composer, I might be switching to CudeMX for a while.
I noticed that the antenna is in the Kicad RF Antenna footprint library as RF_Antenna:Texas_SWRA117D_2.4GHz_Right and RF_Antenna:Texas_SWRA117D_2.4GHz_Left.
I'm currently working on a SAE Hydrogen powered formula and we need a solution for a boost converter. We found some off the shelf solutions but you are slowly making me get the job of developing it! hahahhaha So cool to make the PCB and also the simulation and control are related to my masters dissertation. Oh god i will have to much to do this year
Great video again! Why did you go for the C line and not the S line? Is it because it is RISK V ? Also in the future when you will cover more firmware will you use Arduino or the ESP-IDF?
@27:55 You mention that it is a microstrip and not a coplanar one, about this I have two questions: - why did you go with the former and not the latter? Does Espressif say to use a microstrip for the antenna? - you have pulled the GND plane away from the antenna trace, but the trace is still surrounded by it, at which distance between the two the trace acts as microstrip and not a coplanar microstrip? My understanding is that even of they are separated by let's say 50mm, its still a coplanar microstrip.
If the coplanar copper pour is spaced of at least 3 times the trace width than is influence is low enougth to be ignored (search for 3W rule of thumb). Otherwise you better consider it be a coplanar waveguide.
Wonderful presentation with exquisite explanations! I did have one question though. I attempted to create a similar board with a ESP32C3 SoC. The WiFi didn't work (no reception or transmission). As I reviewed my design, it was nearly identical to yours but I had a 2 layer board vs a 4 layer board that you used. Does having the build use a 4 layer board make that much of a difference? Funny thing is that everything else worked swimmingly.
Thank you! There's a few things that can go wrong - hard to tell without seeing the design. For example, antenna sizing/tuning/placement, matching network, incorrect trace impedance, and so on. Most RF boards are actually 2 layers, so that won't be a problem - but will typically mean wider traces for a given impedance (compared to a board with thinner dielectrics).
Thank you very much for putting time and effort into this great work. I had a question, you interfaced the USB_P and USB_N of the esp-32 with the USB port, thought the USB gives 5 volts which the esp-32 pins can't handle, does this means that the USB ESD Protection will take the 5volts down to a 3.3v, or that the esp-32 USB pins are 5v tolerant.
Nice video, very very useful. Just wanted to ask why did you put a pull-up resistor on pin 6 (GPIO2) and pin 14 (GPIO8)? Is it because of the strapping modes from page 15 of the datasheet? Of all the GPIOs, that two pins are the only ones with a pull-up resistor.
@ Very informative! I always feel a bit smarter after watching your vids. Thank you for covering the ESP 32 and custom PCB antenna design,.plus touching on capacitance,.inductance and impedance tuning of tracks... Plus way more! I'm need clarity about why you have the ground layers in the middle of the PCB. I've seen gnd, signal and pwr planes on the outside... Not sure what effect the order of planes make in PCBs.... With the exception of grounding ic pins with a via, why not use 2 layers for your design? Is it personal choice, best practice, convenient or something else?
The reason why he does that is due to the way how PCBs are constructed. Internally a 4-layer PCB looks like this: 1. copper -prepreg (thin)- 2. copper -core (thick)- 3. copper -prepreg (thin)- 4. copper So the first two copper layers (1 and 2) are very close together, since they're separated by a prepreg, then there is core, which is thick, then the following two layers (3 and 4) are close to each other. The idea here is that you want your signals to have a good reference, which usually is ground. The closer the ground plane is to your signals, the better the reference. This btw has nothing to do with DC, DC will be fine on wires.. But this has something to do with what happens when the signals change e.g. digital signals go from low to high to low... Each change introduces thousands of different frequencies (fourier series), which all need to have a good reference, otherwise they will radiate energy into space until it finds that reference it's looking for. For RF circuits you do not want stray signals flying about, since you care about getting the best SNR from your antenna and stray signals are basically noise, especially when the antenna is passive (PCB antenna, chip antenna) as opposed to active antenna. Plus EMF radiation is increased if you do not have good references, due to which you might fail consumer tests, which will cost tens of thousands to re-test. Anyway, getting back to the subject, why didn't he just use a 2-layer PCB? 2-layer PCB has the following structure: 1. copper -core (thick)- 2. copper It doesn't use prepreg to separate the layers, so unless your PCB thickness is like 0.3mm, you won't have a good ground reference, thus EMF radiation. On top of that, you will have a worse ground return path, since there will be wiring on your ground layer. If you reduce the thickness of such PCB, you will get other problems, since you need both layers to route your signals, singals from the top layer will interact with the signals on the bottom layer, since they are then in close proximity to each other. So again, noise issues, EMF issues, basically at this point you start regretting not going 4-layer board here :) P.s. if you want my recommendation, when you go 4-layer, use 1 and 3 copper layers as GND planes, while the 1 and 2 copper layers will be your signals with power pours in between those signals. The design here requires you to put a GND via next to each signal via to ensure that your return path is good, otherwise again EMF problem! And power pours will ensure good power delivery, since the energy lives not on the copper, but in between the two copper plates. So you want to build a powerful capacitor, which can deliver as much power as needed :)
Thanks you Phil for all the videos you´re making, i´ve learn a lot on pcb design thanks to you!!. Great content and very professional. Since you make the antenna design topic, if you can, could you make something on the "gnss" topic?, based on a module or an IC. Once again thanks!!!
Thanks, Giovanni! Is there anything specifically to a system with GNSS you'd like to see? Usually there isn't much to incoporating those modules in designs.
@@PhilsLab You are right!, i want to implement a ublox module (NEO-M8N) and i saw that the most relevant component it´s an inductor on the antena line for active antennas. But my insecurities appear hahahaha.
As always, a quality content from you Phillip. Thank you for this. Can you also explore STM32WB55 mcu for BLE, We are currently had a designed custom board from this but having some RF issues.
New ESP32 hardware design tutorial coming soon!
Some comments: 1) I'd strongly recommend using off-the-shelf, pre-certified modules unless you have a very good reason not to. This video is more of a 'fun demonstration', rather than something that should be used practically. 2) Although I haven't had issues so far, the chip-enable cap (C19) value should be increased for reliability (as otherwise the default bootmode and chip enable come up at the same time on power on). 3) The antenna matching network and antenna itself will need to be tuned on the real PCB. These are just ballpark values. 4) There is a variant of the C3 (C3FN4) which contains built-in 4MB flash. Meaning you don't need external flash - however, these SPI pins on the C3FN4 cannot be used. Additionally, I believe the C3FN4 is NRND.
Thanks so much for putting this video back up Phil. Me and the rest of the beginner ESP32 designer guys really appreciate it. Why'd you put it back up btw? Also, for any of you guys reading this, you can just use the ESP32-C3FH4X, ESP8685H4, or upcoming ESP8686 for your new designs as they are either active or about to be released.
Thanks for the video. I was debating on either making the antenna design in the PCB or just get the card with the prebuilt antenna. After review of the price, i think its work the extra 50 cents. Unless I somehow sell 100,000 units lol.
I'm hoping is for the ESP32-S3 :)
I'm working on a design for the esp32-s3 so which includes 4mb flash and 2mb SRAM.
My big question is why have the curve in the strip line... If board layout allows, is it permissible for the strip line to be a straight to the antenna feed point (with the PI network added of course)
Once again, Phil has come to the rescue by making a video of exactly what I need, as if by telepathy. This is the 2nd time this has happened and that’s strange.
Glad to hear it's helpful! Hopefully just by coincidence rather than telepathy :D
Next video is Phil's Lab 'Cerebro'...
Ya. Happened to me as well. He's a weird German....in a positive way
@Phil....great job
If I had a nickel for every time that's happened then I'd have two nickels... Which isn't a lot of nickels, but it's weird that it happened twice.
Dude same wtf
I've learned more electronic design from you than the entire five years of my master's of EE university studies.
Glad to hear the videos are helpful - it's a sorry state of affairs when it's this way round though :(
@@PhilsLab The course was very theory-heavy. We never got to actually design a PCB, build it and bring it up.
Thanks to your videos, I'm more confident now designing my own PCBs.
Me too. 6 yrs of grad and 20yrs of work and I never picked up this much.
@ simple question, do you designed pcb with this complexity at school or it was more soft ?
i need to say that you are the best embedded systems channel on youtube by far. watching your videos motivate me to learn more and more and tbh comparing myself to last year i've improved a lot in pcb designs and it's thanks to your videos and robert feranec's. hope you continue this quality containt and thanks for the efforts.
Thank you very much, Yacine! I'm glad to hear that - hopefully I can keep up with interesting videos!
I just want to thank you for your free videos that you release on these topics. It has led me to discover what I want to study in college end goninto as a career. Thanks Phil
That's awesome, thanks!
I have just discovered your channel today and have been watching several of your videos on KiCad and I have picked up a wealth of information, I happen to be in my mid-seventies, a retired electronics design engineer, very much into RF design, and this old dog is still learning new tricks. Well done, Mate! Looking forward to watching more of your Great instructional videos .
Thanks a lot, Harry - glad to have you here! :)
Aww. As someone who’s 25, I always worried that I won’t be able to do as much or learn as much when I’m older because I’m already so much slower than I was since I was a teenager, glad to know that you can still do cool stuff when you age !
100x better than any college course and free. I hope you realize that you’re helping a lot of people!
I was looking for antenna design for esp all over the internet, but all of them were difficult and I lost hope. Now I got your notification, let's see.
Hope it's helpful!
As a rookie PCB designer, I am always in awe of what you do taking us to the design considerations used to produce boards that we buy off the shelf. I have no intention of reproducing this particular design (obviously above my paygrade) but I enjoyed watching the detail description of this author. Thank you very much professor Phil.
You can use the C3FN4 variant of the ESP32-C3 which has a built-in 4 MB flash memory instead of a dedicated memory.
Nice catch
So, in the C3FN4 variant do you just leave one of the SPI pins as Not Connected or can they be used as normal SPI pins?
@@KPruthviRaajas far as i know, other pins need to be strapped - read the doc!
Ironically as it may sound, I was trying to design a depth measure system using the same MCU and a ToF but I found myself with difficulties specially designing the antenna part.
So thank you once again Phil, for the wonderful surprises, and help you've been giving me. Waiting for your new course.
Very glad to hear that! Thank you for your support, Ricardo :)
Literally the exact video I needed. Don’t forget the strapping pins when developing the board. I forgot to pull in of them high when I was designing the board and it caused it to fail when programming. Once I added a trace to 3v3 it all worked again
wow, this is exactly what I have been looking for, the TH-cam algorithm nailed me with this one. Just throwing it out there, but I'd also be really interested in a guide for how to use ceramic antennas in designs
Thanks, Josh - glad to have you here! Great suggestion as well!
This was really what I needed! Created a similar board a few months ago, and this video has really answered a lot of questions I had.
Very glad to hear that, thanks!
Really good video, explains the design process even to those, who don't know all this.
Thanks you!
Phil, congratulations for making such exquisitely detailed videos. You expound every detail, offer practical advice and support for your growing community of subscribers.
Thank you very much for your kind words, Luc!
Wow I've been working on a bare ESP32 project and have been stuck on the antenna part for a while. This video just comes 2 weeks after, amazing thank you so much!
Glad to hear the timing's right :)
Few suggestions: you can use layer 3 or 4 as your ground reference to widen the microstrip trace so the lumped element component pads do not disturb the line width; it's worthwhile to utilize the top layer ground plane, e.g. the grounds of the antenna matching elements can be connected on the top layer for shortest length (inductance) instead of relying on interconnection through vias, the PIFA antenna ground feed should connect to the top layer ground plane, frequently spaced vias connecting the top layer ground plane to the rest of the the ground layers is important; the TI application note PIFA antenna dimensions are for a 1mm FR4 dielectric, it looks like your total dielectric thickness is 1.5mm FR4? This will change the loading on the antenna and require a shorter copper length resonator.
More ESP32 plz. Great video!
THANK YOU FOR THIS!!!!!!!!!!!!!!!!!!!!
I am designing my own ESP32 based board and didnt want to do what everyone else does and just solder on a single ESP32 pre-built board (the one with the wifi antenea and such, not the full dev board, tho i've seen that too).... I am wanting to use the SOC direct and then design my own firmware and setup for it... and the ESP32-S3 is STUPID cheap and so simple!!! I just am getting hung up on the design of the memory and flash and such... I think i'll do an SD card for the flash part... but playing around with options...
I am doing an external antenea plug in on the board since it will be in a case and wanted to have the full range available. But this helps out so much! i've been looking at recommendations from other sites and reading all the SOC documentation inside and out and printed it all out and marking my notes...
This is by far the biggest custom PCB project i've taken on for my own little things... I normally would do the ESP32 and solder the wifi pre-made package board on it. But I wanted something more "professional". Learning to design and build PCB's self taught can be pretty steep learning curve. Only my Electrical Engineering classes in highschool from the late 90's is what I have education wise and all self taught componant diagnosis and repair and small self designed PCBs.
But NO ONE has an SOC totorial for me to go through and verify my design and deployment based off the technical and design documentation from espressif direct.
New sub from me! Love this walk thru! Simplified some of my questions I was dealing with trying to figure out via documentations.
Your video is great and saved me from making a critical error. I read the docs and didn't see anything about the LNA_IN output impedance (35 + j10) so assumed it was 50 ohm since that's the "standard". Turns out its not listed in the datasheets but is mentioned on the hardware forum.
Thanks, glad to hear that it helped!
Very detailed video about the whole steps that is essential to create an excellent PCB! But I have one suggestion for improvement that you can comment on: It's necessary for PCB antennas to open solder mask above them. Solder mask dielectric constant can dramatically change the characteristics of the created antenna, because it is located in the path of radio waves propagation.
Question: without soder mask, the antenna will then be affected by the finish (ENIG or HAS). Wouldn't that affect also be an unknown variable?
@@RSP13maybe - but the antenna / unit would probably be used indoors - so you wouldn’t necessarily have to worry about corrosion. If outdoors then one would assume it’d be housed in suitable enclosure. Outdoor antennas are constructed in aluminium - & some say not to clean them as the effects of environment on the surface of the antenna can improve performance!
I am learning enormous things from your tutorials ....Really thanks
Thanks for watching :)
For my semester project i literally have to implement an ESP32-C3. It is as if god sent you Phil.
Awesome, good luck with your project!
As others previous replies - thank you for the step through of the design & great video.
I only chanced on this video by googling the chip reference / & interest on the antenna design.
With your simplified approach using what’s been done before & reference to the paper is very practicable too. I’ll be off to read that now.
I saw another TH-cam where the antenna is printed on both sides so that’ll have some new techniques/benefits one presumes.
Atb
Awesome, I've never saw those unique ESP32 design! Thank you for great video.
Thanks for watching!
Thanks for your content! It is amazingly useful for learning. I'm considering to use the ESP32-C3 for my next project 😁
Thanks for watching, Sergio!
Great video!
I've been working with ESP boards for years now (developing ESPEasy) and I alway wondered what made one board work great with WiFi and why it worked so bad on others.
I really would like to know how the WiFi quality is of this board, compared to other boards when running the same kind of scan at the same location in your house.
Maybe also nice to check running some AP on various channels to see whether you hit the perfect center frequency and what the actual bandwidth/range is of your PCB antenna.
Perhaps let some ESP board run a few meters away, starting AP mode on the next channel every minute and let your board (and others) scan and compare the RSSI values.
Still this will of course also include some offsets caused by the "bad" antenna of the other ESP board acting as an AP.
So maybe you could also test using a real access point and test on channels 1, 6 and 11 to cover the entire 2.4 GHz spectrum.
Also really nice to see those ESP32-C3 are so easy to wire and program due to their internal USB interface.
Meaning I really should start supporting the C3 also in ESPEasy :)
Truly amazing content, a lot of different subjects, HW, SW, indepth practical design. Thank you so much
Thank you for watching, Rick!
@@PhilsLab are you maybe planning on a similar board with some LoRa IC + PCB antenna?
Hi Phil, Nice video overall. It was refreshing to hear you admit that there were going to be many external factors that will impact the overall tuning of the onboard antenna. A very realistic approach since the end user can put the board into a completely unknown environment with various other nearby metalic elements which will all impact upon the tuning and performance of the antenna. It was amusing to then see you worry about the PI matching network to match the 35j10 to the 50 ohms (nominal) IFA impedance. If by some chance your antenna ends up at 50 ohms (unlikely in the real world) without any actual verification / trimming then the power loss from the resulting mismatch is still pretty much negligible. All made more novel by the "close enough" values of the PI elements ;-) I realise the whole point is to demonstrate a complete RF path from the chip to the antenna and you did that well. Some people go to extraordinary lengths to try and get the match of some onboard antenna and matching network perfect whilst ignoring the reality that it will only ever be "right" at that moment in time on their bench lol.
Just one more thing, in your layout you had the PI matching network inductor close and parallel to (I think) one of the RF power rail inductors. Personally I'd seperate those or put them at right angles to reduce any possible coupling but it again may make no practical difference! I'm not going to touch the whole solder mask or not issue in the RF path. All the best.
Funny to see you here. I cannot imagine who you may be referring to above... 🫠
Thank you! I thought to make custom esp32 board with pcb antenna and after research came up with similar guidelines. But did not make it yet ... :) Now I will have more confidence that this thing will work, can't wait for your next videos!
Thank you, Dmitriy - good luck with your design!
Thanks for the video, it is really informative and I am glad that the content is of such a high quality! I had a couple of questions though. First of all, could you have just connected the antenna ground pin to the GND plane on the top layer. Of course adding a via to GND is also a neccessity there, but it seems against any logic not directly grounding that pin to the top layer of the ground. I checked some designs online and I see this being grounded to the top (if the top pour is GND that is). So potentially did you manage to find some information that was against doing this? Another questions is that I see people adding a picket-fence around the antenna feed line and the antenna itself, which should reduce stray signals from antenna entering the PCB and the opposite. I thought it is quite essential, but you seem to have managed to make it work without adding one. I wonder how would that affect the SNR overall.
Awesome video Phil, an absolute joy to watch and learn. Was looking into antennas in general and wanting to learn. This would be a great start! Thanks again!
Thank you very much! Hope this proves to be helpful for your designs :)
@@PhilsLab You know how you can add comments within the code you write, is there a similar thing with Altium or any designer? Watching you explain diff sections of the schematic, I imagine having comments show up in a window on the side would be great. How do teams work together to design stuff?
Video is gold, I´ve seen extremely few people going over so much detail and the correct reason behind it over the years. And yes, technically you are being a bit naughty with the USB. As per IF-standard you should not draw more than 100mA continuously before enumeration, that being said, you would probably still be fine, if the first thing that you try to do when the device connects is to try to enumerate before activating the RF section. I do not know the C3 specifications, but I would guess, if you really wanted to turn this into a product with the USB-IF approved logo on the outside, it should not be a problem. But rumor has it, they turn a blind eye with a lot of products anyhow.
Thank you for sharing your knowledge with us! Great video, as usual, but I would like something similar made with KICAD if possible.
Yeah mate.
Need more videos in KiCad as I'm a beginner.
I manufactured an ESP32-S2 board and the impedance I got on the RF input was very different from the one on the datasheet ( 11 + 1j vs 31 + 1j ). This means the impedance matching network I designed actually reflected 95% of the signal at the 2.4Ghz carrier frequency, it actually worsened the problem instead of improving it, as removing the network and using a 0 Ohm resistor only reflected 50% of the signal. I have to say my stackup was completely different too from the one recommended in the datasheet. It might be worth to mention to ALWAYS leave an u.FL connector on the board to hook up a vector analyzer in case it doesn't work properly (and it will not if you make even a slight change on the stackup)
I might mention, the change I did to the stackup was using 0.8mm thick 2 layer board instead of 1.6mm thick 4 layer board. It also changed the impedance of the PCB antenna from 50 + 0j Ohms to 30 + 0j Ohms. Luckily I left an u.FL connector in place to know this information, and also pads to solder a Pi Network on the antenna end
Sir, could you tell me in what position did you place the U.FL connector? Was it between the ESP pin and the matching network or between the matching network and the PCB antenna? Thanks.
Very good! It’s a reminder if you depart from what has been tried / tested & used you might fall foul on the required design.
Ok with a matching network to suit.
Interested to know how you measured the above.
@@avinadadmendez4019stack up? I saw on another video where the antenna was printed on both sides of the pcb - as a stacked antenna
This is amazing. I learned so much.
I made a pcb a couple of weeks ago and I thought I did quite well but I now know there are so many small mistakes in it after seeing this video haha.
It might be fun to do a video about my pcb and point good/bad things out along the way.
Thanks, Emiel! I do design reviews on the channel, if you'd like - send it in via phils-lab.net/contact :)
@@PhilsLab hi thank you for your reply.
I have sent my design in via the link you gave me. If there are any questions please let me know.
I hope my design is not too bad 😬
I was waiting for a video like this for so long!!! Thanks you Phils
Thanks for waiting! :)
You haven't explained the 35+j10R term yet. When I look at the ESP32 Drvboard V1 I see this PCB antenna directly connected without a matching network, because nominally the pin 1 is designed for 50 Ω and the devboard doesn't use any more matching.
Great video Phil! Certainly a project I’m planning on doing at some point. Love the Wi-Fi name!
Haha thanks, Alex!
Oh yes exactely what I was waiting for!!! Thanks!
Glad to hear that - thanks for watching!
@@PhilsLab Could the ESP32 c3 also be used to negotiate other USB-PD voltages or would I always need a separate IC for that?
I guess you could try and control the CC lines through the ESP32 directly, but it's far easier to use a dedicated USB C PD IC, which interfaces to ESP32 via I2C, for example.
@@PhilsLab Okay so if it's a size-constrained application it might be possible but if I have the space is probably not worth the hustle. Thanks!
You'll have to add in control circuitry + FETs as well in any/most cases, so I'd definitely just go with a dedicated controller that has the right gate drivers, etc. as well.
Very cool video! I design hardware with the ESP32 Wroom modules for work so it's super cool to see a design with the ESP32 C3 chip itself
What does your company make? Seems weird as we are not allowed to use esp32 as it's not 'a real mcu'. We use pic24, FPGAs, etc
Thank you so much for making this video. It gives me alot of insight of making pcb board with MCU, i am wondering you like to add CLC pi filter to the power supply and analog supply, any tips for this kind of filter? For eg how to select the right value of the components. Thank you!
Very nice, I was designing esp32 data logger some time ago, and I remember including "reset" circuit connected to the external IC USB to UART and that had Data Terminal Ready and Ready to Send control output connected through two transistors to the EN and BOOT pin on ESP32, that helped with the reset after sketch upload. I wonder if this can be implemented in the SOC when the UART chip is "build in"
Once again, a great video and very informative. Looking forward to the further firmware videos with this board.
Thanks, David - firmware video coming out this month!
Thank you Phil for another awesome pcb project video!
Thank you very much for watching!
After this being the somewhat twenty-x-ish video of Phil I watched, I realised I have not yet subscrided to this channel, which I "fixed" immediately. I would love to hear and see even more about design considerations for EMI/SI ,because at least to me it appears that most people (including me) have still a lot to learn in this field.
Glad to hear that you subscribed!
Definitely will be making more videos on SI/EMC techniques.
I was looking for something like this too…. Phils lab is theee best!
Awesome, glad to hear that!
Golly! great video!!!!!!!!!
Thanks, Tony!
Great video as always! Looking forward to more videos on this board's capabilities!
Thanks, Louis!
Amazing project! I'll hope you'll continue with it!
Thanks! Firmware videos coming next :)
Could you please make a video on GPS module/ system design
Just for anyone watching, there is a version of C3 with built in flash as well (C3FN4, C3FH4, 4MB flash). I've used it on my own board and I thought that meant the SPI pins could be used for other things then but appears that the internal flash is connected to the same pins as they would for external. (yes I know it's stated in the datasheet that these pins are not recommended for other use, but I thought that was fi external flash was used). So good to know so you don't do the same mistake as me. :).
Thanks for the informative video. Is there any guidance on these ground planes on the top layer? Why some designs have them, but others don’t? When holes are required? Why there are some uncovered blanks spots?
I enjoy your AP name being "Cheeky WiFi 'n That"
Haha I've been listening to too much Karl Pilkington...
@@PhilsLab "not getting on a camel" is a frequent reference in my household
great video, always blown away
Thank you, Jack!
Cheers, Phil. Amazing content.
I love it! only thing missing, is a CAN bus IC (SN65HVD230DR). 😅
Thank you so much for your informative tutorials
For me the in between here is the Espressif modules. Not dev boards, the modules. They come with the flash already setup under the can and ... quite importanly an FEC Certificate of compliance. The chips on the other hand do not come pre-certified so any product that wants to carry the logo and get an ID has to go through it's own certification, submit it's own test/lab results etc.
FCC* ?
you have to do the FCC testing for the whole device anyway.
@@martincerny3294 true, so why complicate things? Pre-shielded mcus makes it for easier self certification, where acceptable,jurisdictionally, no?
This content is worth a lot, I struggle to find books and Udemy courses that will teach me more about embedded systems on this level. Please consider turning some of your work into Udemy courses in future.Thank you.
Phil i ove your videos. so clear, clean, ogranized and amazing in general. so informative. please do one with standalon bluetooth audio SOC. I will forever be grateful.
Thank you very much, Srijan!
Hi Phil,
Thanks for the video! Your content is more detailed than most videos I find on TH-cam.
I am designing a board based on the ESP32. The documentation says that to ensure the power supply to the ESP32-S3 chip is stable during power-up, it is advised to add an RC delay circuit at the EN pin. The recommended settings for the RC delay circuit are usually R = 10 kΩ and C = 1 µF. However, I am not able to find the rise time anywhere in the documentation to calculate the correct values for R and C.
how can i find those values
Hi Phil! Great resource to have as I am trying to use the bare ESP32 chip instead of a pre-made module. Could you please shed some more light on the Q24FA20H0020900 crystal you have selected here and how you derived the load capacitors at the 10pF level? Is the stray capacitance something you measured yourself? The datasheet for this crystal is not clear at all...... Thanks
Hi Matthieu, Thanks! As a rule of thumb, stray capacitance Cs is 2 to 5pF (due to PCB pads, routing, ...). You'll need to get the load capacitance of the crystal from the datasheet (e.g. Cl=9pF). Then to work out the value of the load capacitors, simply use CLOAD=2*(Cl-Cs). A ballpark value is fine (due to not knowing the stray capacitance exactly).
Thank you so much for making this great, educational video.
With the implementation of the PCB antenna and matching network, how do you know if the design achieved a low SWR? Is there any practical way of measuring it?
NanoVNA
Very nice! Thanks for the video - I enjoyed it as usual. By the way, you should change your wifi access point off of channel 6. According to your new scanner that band looks quite congested :)
Please, include schematics that you have created. ESP32-C3FN4 comes with 4MB embedded flash. What would be the diffrence in schematics in that case?
Is there a reason you did not use the ESP32-C3FN4/H4? These do include integrated flash while the default version does not.
And thank you so much for this video. This is beyond helpful. I have recently made a design with this chip and it was quite the learning experience to create my own non-module ESP32 PCB. I couldn't believe JTAG was built-into the chip. Cheers!
No particular reason other than showing how an external flash chip would be integrated. The FN4 design is definitely simpler/smaller with a similar cost.
Glad to hear the videos have been helpful, thanks for watching!
Wow, really cool. First of all, your video with the ESC FOC controller helped me, because I was experimenting with BLDCs at that time and now this year I wanted to start a project with an esp32. Thanks for that. Will there be another video about the ESC and the FOC? Many greetings Michael. The content on your channel is great and so helpful.
Thanks, Micha. Glad to hear the videos have been helpful. Yes, I'd like to make a follow up vid to the ESC design, however, I have many projects ongoing at once, so it can take a bit of time I''m afraid.
Super impressive and relevant
I'm a beginner doing electronic boards and try about five times to make a functional ESP32 custom board using a lipo battery and I failed in all tries. I will try to do a new board again using your example. Wish me luck.
Good luck with your new board, Daniel!
I have found SimSmith (free JAVA-based software) excellent for designing various matching networks. Of course, a basic understanding of Smith Charts is needed but the program will choose "standard" values for the various network types you want to implement and give you a pretty good Smith Chart representation of how it should react (also Bode plots).
Yes, I use SimSmith myself sometimes as well - really neat tool.
your videos are soooo invaluable. thank you
Thank you!
Phil. Great videos. Leant much. Why did you terminate the GND of the antenna at the GND pour directly instead going have a gap around that leg?
Amazing! Thank you so much for sharing. Did someone send this to PCBway for manufacturing and assembly? I would like to know how expensive it is.
Something that I would like to know is how do you define the parameters when you order it. Obviously, impedance control is a thing, but what other specific parameters are needed to order it?
Amazing video again 😍
Hope yo do same video for a GPS module
Because i have to put components on the pcb with its antenna but i didn't find much resources
An altium, procad and ultimate kicad user. I appreciate your reverence but my unemployed world means altiium isn't an option.
Great tutorial. Just one question. Why you don't choose the ESP32-C3FH4 version which include 4Mb Flash memory ?. Is there any downside to this choice ?
Thanks! To be honest, I can't remember why I chose this one - maybe to show how to hook up an external flash? In any case, as you say, the *FH4 version is simpler to integrate with.
Great video again Phil, love it. I downloaded STM32CubeMX and have been working through the tutorials. The software sounds awesome. I usually use Studio code composer, I might be switching to CudeMX for a while.
Thank you very much, Bill. If you haven't already, I'd highly suggest given the newer STM32CubeIDE a try!
@@PhilsLab I already downloaded it. I got my hands on a STM32 nucleo. I also enjoy using MSP430 series as well.
I noticed that the antenna is in the Kicad RF Antenna footprint library as RF_Antenna:Texas_SWRA117D_2.4GHz_Right and RF_Antenna:Texas_SWRA117D_2.4GHz_Left.
I'm currently working on a SAE Hydrogen powered formula and we need a solution for a boost converter. We found some off the shelf solutions but you are slowly making me get the job of developing it! hahahhaha So cool to make the PCB and also the simulation and control are related to my masters dissertation.
Oh god i will have to much to do this year
Haha glad to hear this is making you do design work! :D
Very nice video, TNX Phil.
Thanks, Nicola!
Can you make a video discussing high current or high power switching devices like relays?
I used Ti's ISM PCB antenna app note for Lora pcb design, fortunately they had shared gerber so creating footprint was a breeze
Great video again!
Why did you go for the C line and not the S line? Is it because it is RISK V ?
Also in the future when you will cover more firmware will you use Arduino or the ESP-IDF?
You are Awesome
@27:55 You mention that it is a microstrip and not a coplanar one, about this I have two questions:
- why did you go with the former and not the latter? Does Espressif say to use a microstrip for the antenna?
- you have pulled the GND plane away from the antenna trace, but the trace is still surrounded by it, at which distance between the two the trace acts as microstrip and not a coplanar microstrip? My understanding is that even of they are separated by let's say 50mm, its still a coplanar microstrip.
If the coplanar copper pour is spaced of at least 3 times the trace width than is influence is low enougth to be ignored (search for 3W rule of thumb). Otherwise you better consider it be a coplanar waveguide.
Wonderful presentation with exquisite explanations! I did have one question though. I attempted to create a similar board with a ESP32C3 SoC. The WiFi didn't work (no reception or transmission). As I reviewed my design, it was nearly identical to yours but I had a 2 layer board vs a 4 layer board that you used. Does having the build use a 4 layer board make that much of a difference? Funny thing is that everything else worked swimmingly.
Thank you!
There's a few things that can go wrong - hard to tell without seeing the design. For example, antenna sizing/tuning/placement, matching network, incorrect trace impedance, and so on.
Most RF boards are actually 2 layers, so that won't be a problem - but will typically mean wider traces for a given impedance (compared to a board with thinner dielectrics).
Great tutorial! Thank you
Thank you!
Thank you very much for putting time and effort into this great work. I had a question, you interfaced the USB_P and USB_N of the esp-32 with the USB port, thought the USB gives 5 volts which the esp-32 pins can't handle, does this means that the USB ESD Protection will take the 5volts down to a 3.3v, or that the esp-32 USB pins are 5v tolerant.
This is fantastic, thanks
Thanks, Juma!
Nice video, very very useful. Just wanted to ask why did you put a pull-up resistor on pin 6 (GPIO2) and pin 14 (GPIO8)? Is it because of the strapping modes from page 15 of the datasheet? Of all the GPIOs, that two pins are the only ones with a pull-up resistor.
@ Very informative! I always feel a bit smarter after watching your vids.
Thank you for covering the ESP 32 and custom PCB antenna design,.plus touching on capacitance,.inductance and impedance tuning of tracks... Plus way more!
I'm need clarity about why you have the ground layers in the middle of the PCB. I've seen gnd, signal and pwr planes on the outside... Not sure what effect the order of planes make in PCBs.... With the exception of grounding ic pins with a via, why not use 2 layers for your design? Is it personal choice, best practice, convenient or something else?
The reason why he does that is due to the way how PCBs are constructed. Internally a 4-layer PCB looks like this:
1. copper
-prepreg (thin)-
2. copper
-core (thick)-
3. copper
-prepreg (thin)-
4. copper
So the first two copper layers (1 and 2) are very close together, since they're separated by a prepreg, then there is core, which is thick, then the following two layers (3 and 4) are close to each other. The idea here is that you want your signals to have a good reference, which usually is ground. The closer the ground plane is to your signals, the better the reference. This btw has nothing to do with DC, DC will be fine on wires.. But this has something to do with what happens when the signals change e.g. digital signals go from low to high to low... Each change introduces thousands of different frequencies (fourier series), which all need to have a good reference, otherwise they will radiate energy into space until it finds that reference it's looking for. For RF circuits you do not want stray signals flying about, since you care about getting the best SNR from your antenna and stray signals are basically noise, especially when the antenna is passive (PCB antenna, chip antenna) as opposed to active antenna. Plus EMF radiation is increased if you do not have good references, due to which you might fail consumer tests, which will cost tens of thousands to re-test. Anyway, getting back to the subject, why didn't he just use a 2-layer PCB? 2-layer PCB has the following structure:
1. copper
-core (thick)-
2. copper
It doesn't use prepreg to separate the layers, so unless your PCB thickness is like 0.3mm, you won't have a good ground reference, thus EMF radiation. On top of that, you will have a worse ground return path, since there will be wiring on your ground layer. If you reduce the thickness of such PCB, you will get other problems, since you need both layers to route your signals, singals from the top layer will interact with the signals on the bottom layer, since they are then in close proximity to each other. So again, noise issues, EMF issues, basically at this point you start regretting not going 4-layer board here :)
P.s. if you want my recommendation, when you go 4-layer, use 1 and 3 copper layers as GND planes, while the 1 and 2 copper layers will be your signals with power pours in between those signals. The design here requires you to put a GND via next to each signal via to ensure that your return path is good, otherwise again EMF problem! And power pours will ensure good power delivery, since the energy lives not on the copper, but in between the two copper plates. So you want to build a powerful capacitor, which can deliver as much power as needed :)
Thanks you Phil for all the videos you´re making, i´ve learn a lot on pcb design thanks to you!!. Great content and very professional. Since you make the antenna design topic, if you can, could you make something on the "gnss" topic?, based on a module or an IC. Once again thanks!!!
Thanks, Giovanni! Is there anything specifically to a system with GNSS you'd like to see? Usually there isn't much to incoporating those modules in designs.
@@PhilsLab You are right!, i want to implement a ublox module (NEO-M8N) and i saw that the most relevant component it´s an inductor on the antena line for active antennas. But my insecurities appear hahahaha.
Finally, this topic😂
Briliant video, would have been awesome if it was kicad as Altium is out of my reach... cant even get the free trial with altium :(
Great, Can you share the Altium files for this design?
As always, a quality content from you Phillip. Thank you for this. Can you also explore STM32WB55 mcu for BLE, We are currently had a designed custom board from this but having some RF issues.
Thank you, Ian! The STM32WB* series is definitely something I'd like to feature in upcoming videos.
The Espressif guideline for PCB antenna is no ground plane underneath.