I used these in the 80’s when I did an internship at the research lab of our national telecom company. Nowadays I use the MAR-3 and MAR-6 in my homebrew ham radio projects. They work very well.
The parts I used back in the day in this micro-X (or TO-50) package were dual-gate MOSFETs such as BF960/980. Very useful as either cascode-on-a-chip, mixers, AGC etc
Often used as a second stage after a GaAsFet in preamps used on 13 and 24cm. You'll find plenty of designs in old issues of CQTV. At those frequencies, the RF choke can be just a few turns made from the lead of the bias resistor.
What some people miss is the importance of the Noise Figure in these amplifiers. Gain is one thing, but maintaining a good S:N in your design is more effective. Getting a 3dB NF in such a small 50 ohm package is very useful.
1dB compression point, bandwidth, gain, operating current, and noise figure are specified for each type in the MAR series. 'brown dot' MAR-1 is what I spec'd for a service monitor back in the '80s. Bought them in hundred lots for $1ea. Very reliable for anything level 7dBm (double balanced mixers like SBL-1 or TFM-2) and very simple to use: 1/8 watt metal film (Vcc - 5v / 17ma) .039ufd 0805 coupling caps (100kHz - 1GHz). Used them as receiver inputs, interstage buffer/isolation/gain with 3dB pads to double tuned filters, output amplifiers up to +10dBm, etc. Never had a failure because of them! noise figure: I modified a couple receivers to .15uv (12dB Sinad) with MAR-1 as input amplifier and they worked just fine; nobody else made anything close for 10X the cost. SWR is really good across 100k - 1G (antenna matching is more important); better than similar Gasfet or bipolar designs and broadband with good IMD. One of these in an ALTOIDS mint tin with F type connectors and a 9v battery makes a great temporary TV antenna booster; sensitivity of modern large flatscreens is really poor, they are built for cable or HDMI inputs, gaming etc. (100 hour intermittent, alkaline) BNC's or whatever for DXing ham radio...
Online databases, e.g. ultra-librarian, contain a footprint for the MAR-4SM which might be useful as a starting point. Obviously you would still need to customize it for your PCB material and stackup.
14g with insulation (pulled from cheap house romex) glued flat on a ground plane is good enough 50/75r match for most DIY applications (3:1). MAR-1 are rugged and very tolerant of SWR
Extreme bandwidth for audio is more likely to cause oscillation problems. NE5532's are way better and dirt cheap, too. Moving coil preamp would have too much 1/F noise, worth a try just for fun.
Wow 'strip line' parts. found a few resistors and caps of these in a 'Junk Box' I inherited from an even older guy, took me forever to find out what they are still have no idea on how to use them.
+ at the end of part number means RoHS compliant
I used these in the 80’s when I did an internship at the research lab of our national telecom company. Nowadays I use the MAR-3 and MAR-6 in my homebrew ham radio projects. They work very well.
The parts I used back in the day in this micro-X (or TO-50) package were dual-gate MOSFETs such as BF960/980. Very useful as either cascode-on-a-chip, mixers, AGC etc
Often used as a second stage after a GaAsFet in preamps used on 13 and 24cm. You'll find plenty of designs in old issues of CQTV. At those frequencies, the RF choke can be just a few turns made from the lead of the bias resistor.
"Expected MTTF (mean time to failure) is 15,000 years at 85°C case temperature."
Must be nice to have a time machine to do long term testing like that. Didn't realize Mini-Circuits was so advanced. 🤣
at 2:00
What some people miss is the importance of the Noise Figure in these amplifiers. Gain is one thing, but maintaining a good S:N in your design is more effective. Getting a 3dB NF in such a small 50 ohm package is very useful.
1dB compression point, bandwidth, gain, operating current, and noise figure are specified for each type in the MAR series.
'brown dot' MAR-1 is what I spec'd for a service monitor back in the '80s. Bought them in hundred lots for $1ea. Very reliable for anything level 7dBm (double balanced mixers like SBL-1 or TFM-2) and very simple to use: 1/8 watt metal film (Vcc - 5v / 17ma) .039ufd 0805 coupling caps (100kHz - 1GHz). Used them as receiver inputs, interstage buffer/isolation/gain with 3dB pads to double tuned filters, output amplifiers up to +10dBm, etc. Never had a failure because of them!
noise figure: I modified a couple receivers to .15uv (12dB Sinad) with MAR-1 as input amplifier and they worked just fine; nobody else made anything close for 10X the cost. SWR is really good across 100k - 1G (antenna matching is more important); better than similar Gasfet or bipolar designs and broadband with good IMD.
One of these in an ALTOIDS mint tin with F type connectors and a 9v battery makes a great temporary TV antenna booster; sensitivity of modern large flatscreens is really poor, they are built for cable or HDMI inputs, gaming etc. (100 hour intermittent, alkaline)
BNC's or whatever for DXing ham radio...
Online databases, e.g. ultra-librarian, contain a footprint for the MAR-4SM which might be useful as a starting point. Obviously you would still need to customize it for your PCB material and stackup.
14g with insulation (pulled from cheap house romex) glued flat on a ground plane is good enough 50/75r match for most DIY applications (3:1).
MAR-1 are rugged and very tolerant of SWR
Oh wow. I remember these from 1992!
Idea: Chip of the month club. Various circuit builds using CotM.
Seeing how well you get the impedance match with new board will be interesting.
Looking for the next video where you characterize these. I've always wanted to use these but never have played with them!
2:43 15000 years
With DC to GHz bandwidth, I'm curious how these would work as an audio amplifier.
Extreme bandwidth for audio is more likely to cause oscillation problems. NE5532's are way better and dirt cheap, too.
Moving coil preamp would have too much 1/F noise, worth a try just for fun.
minty circuits
Wow 'strip line' parts. found a few resistors and caps of these in a 'Junk Box' I inherited from an even older guy, took me forever to find out what they are still have no idea on how to use them.
We're can I purchase I'm in UK
Mouser has them