Is this possible to add subtitles for this video in English..? your videos are great and amazing.. It will appeal more audience if they are English.. Thanks !
Whoa, this one looks simple compared to Ali Hajimiri's calculation! Ali is an excellent lecturer but he is too much mathematics for me. Purely formula, zero real world examples. Is differential amplifier best use with PFET than NFET? What happens if I flip the whole thing? By 'flip' I mean NFET current mirror, PFET active load, NFET differential input. What I understood is that N material of MOSFET and NPN BJT is more efficient for electron flow compared to P material. It is no wonder why most P-channel MOSFET has high drain-source resistance. Very low resistance PFET is crazy expensive! I know that P stuff are expensive too produce. However I am only an end-user, so N stuff are the way to go price wise and efficiency wise. PFET becomes madly uneconomical considering if more than one is needed. In my humble experience only one situation NFET gives me a pain in the neck is is making "high side" switching or reverse polarity protection. PFET is always used on this matter because it is extremely straightforward. NFET is rarely used for this purpose because needs a so-called "driver". I dislike extra work and using too much brain power, but a necessity to me when cost is a concern. Using a few NFET is still much cheaper than one PFET! (Price depends on which NFET of which company and "special" characteristics. But NFET is generally a lot cheaper than PFET)
Which one is better ?PMOS or NMOS as the input differential pair? I think the answer depends on what purpose your amplifier is used for. For example, most of my past experience is to use the amplifier as the first-stage amplifier after the sensor output. Therefore, the noise of the amplifier is very important to me. Moreover, the signal of the sensor is mostly below 10KHz (for example: accelerometer, magnetometer, thermometer), so the noise I consider is flicker noise. PMOS usually has a small flicker noise in the CMOS process, so I will choose PMOS as the input differential pair.
@@ericyeh3787 This is new information for me! I learn new things every day! I did not know and I am very sure that I am not being understood that PMOS usually has a small flicker noise in the CMOS process! There could be TH-camrs or Internet saying this but I could miss that part. Noise is very important to me too. It is more psychological than physical in my case. What I planned to make was an audio amplifier, with NE5532 or NJM5532. It is said that this chip is very noisy. Now I think I know the reason why. It is because that chip is said to be NPN configuration, which it is! Although part of audio frequencies are also right below 10 kHz, flicker noise is not really audible. According to a site, the author says that people overly concern about audio noise from (any audio) chip is nonsense because the noise is not audible, it is audible (seeable) only if we use an oscilloscope or listen for it really very hard or turn on the volume extremely loudly. Like a perfect image will have flaws if we pixel peep hard, zoom the image in to the pixels.
Hi Thanks for the intuitive explanation. You're a good analog designer.
相同的(gm/id) 意味著相同的Vgs-Vt.而(M3,M6,M7)是相同的(gm/id),影片中是選定10(因為M3,M6,M7是電流源).
在影片22:20為了將second pole推到(2.5~3)倍的 GBW而算出Gm8的值.從這裡我的認知就有點不同了,因為ID8=ID7, 所以 M8的(gm/id) = Gm8/ID7,且(M4,M5,M8)是相同的Vgs-Vt,所以 M4,M5的gm/id只好配合與M8相同,不見得是原先設定的10(當初是因為M4,M5當電流源而選定gm/id = 10)
為何458要相同Vov
ID8与ID7并不相等吧，还有Iout
计算Gm的值出了一点小差错，一开始计算的是1.3mS,后来写成了13mS,导致整个电流都偏大了，不过不影响设计流程
謝謝～非常棒的課程！
Is this possible to add subtitles for this video in English..? your videos are great and amazing.. It will appeal more audience if they are English.. Thanks !
Hi Eric, I wanted to ask that at 20:20, you wrote the formula of Fnd, and multiplied that to 1/1.3. What was that 1.3?
hi! He said that it was according to his experience and simplified this formula to given a number, it is not a 'strict theory' formula.
應該是CL加上元件寄生電容，大約乘以1.3倍
想請問如果遇到GBW要求不高，導致Id1,2算出的電流太小，不足以讓電晶體進入飽和區的情況，應該如何解決？
感謝老師！但我有個問題
gm/Id大不代表gm大對吧 (?)
照著上面的計算gm1,2 = 13mS，並取M3的gm/Id為10的話，算出來的gm3會是16.2mS，反而比gm1,2還大，
與一開始說的"電流源gm要小"似乎有點矛盾 ，是什麼地方我弄錯了嗎
因為M3的電流是M 1和 M2的兩倍，所以相對來說gm會大一些
電流源gm要小的前提是考量雜訊並已知電流的情況下，把gm/id做小，可以降低電流雜訊
例如都是10uA的電流源，如何選取電晶體的size?考量雜訊的情況下我們會設計size讓gm小一點，自然gm/id就會小
感谢老师！我有一个问题，就是我看到视频中都是直接假定一个L进行设计，但是如果我的Cascode Amplifier对直流增益有要求的话，L很难直接确定。而短Channel模型下L和Vth等参数都有比较大的影响，那这种情况我应该怎么确定L呢？是先随便设置一个值，然后最后再根据要求进行Scaling吗
是這樣沒錯，一般而言，使用gm/id 的設計方法就是避免要去面對vth 這類隨製程corner 變化的參數
Hi Prof. please correct the + and - terminal of the opamp
Thank you for your reminder, I’ll add the note below the video.
v+ v-是不是寫反了?
Hi, Could you please, provide this tutorial in English.
Thanks in advance.
I’ll try. Thanks for your suggestion.
Whoa, this one looks simple compared to Ali Hajimiri's calculation! Ali is an excellent lecturer but he is too much mathematics for me. Purely formula, zero real world examples.
Is differential amplifier best use with PFET than NFET? What happens if I flip the whole thing?
By 'flip' I mean NFET current mirror, PFET active load, NFET differential input.
What I understood is that N material of MOSFET and NPN BJT is more efficient for electron flow compared to P material. It is no wonder why most P-channel MOSFET has high drain-source resistance. Very low resistance PFET is crazy expensive! I know that P stuff are expensive too produce. However I am only an end-user, so N stuff are the way to go price wise and efficiency wise. PFET becomes madly uneconomical considering if more than one is needed.
In my humble experience only one situation NFET gives me a pain in the neck is is making "high side" switching or reverse polarity protection. PFET is always used on this matter because it is extremely straightforward.
NFET is rarely used for this purpose because needs a so-called "driver". I dislike extra work and using too much brain power, but a necessity to me when cost is a concern. Using a few NFET is still much cheaper than one PFET! (Price depends on which NFET of which company and "special" characteristics. But NFET is generally a lot cheaper than PFET)
Which one is better ?PMOS or NMOS as the input differential pair? I think the answer depends on what purpose your amplifier is used for.
For example, most of my past experience is to use the amplifier as the first-stage amplifier after the sensor output. Therefore, the noise of the amplifier is very important to me. Moreover, the signal of the sensor is mostly below 10KHz (for example: accelerometer, magnetometer, thermometer), so the noise I consider is flicker noise.
PMOS usually has a small flicker noise in the CMOS process, so I will choose PMOS as the input differential pair.
@@ericyeh3787 This is new information for me! I learn new things every day! I did not know and I am very sure that I am not being understood that PMOS usually has a small flicker noise in the CMOS process! There could be TH-camrs or Internet saying this but I could miss that part.
Noise is very important to me too. It is more psychological than physical in my case. What I planned to make was an audio amplifier, with NE5532 or NJM5532. It is said that this chip is very noisy. Now I think I know the reason why. It is because that chip is said to be NPN configuration, which it is!
Although part of audio frequencies are also right below 10 kHz, flicker noise is not really audible. According to a site, the author says that people overly concern about audio noise from (any audio) chip is nonsense because the noise is not audible, it is audible (seeable) only if we use an oscilloscope or listen for it really very hard or turn on the volume extremely loudly. Like a perfect image will have flaws if we pixel peep hard, zoom the image in to the pixels.
感谢
Add subtitles please
please make it in english.
媽媽
In English please 😭