TopBand: High input intercept devices

Peter Chadwick Peter_Chadwick@mitel.com
Thu, 9 Apr 1998 09:55:42 +0100


W5PS says;

>I saw a note from Carl, KM1H talking about how bad surface mount devices
>can be for intermodulation products. Thier is a company in California
>called Stanford Microdevices which manufacturers small inexpensive
>packaged MMICs in a micro-X package. They require +5v supply and have a
>IIP3 of +27dBm. These devices operate from DC (low freq) to 3Ghz. The
>part number with the mentioned IIP3 is the SNA-686 it costs about $5 for
>1 piece. They are Class 1 ESD sensitive since they are GaAs HBT devices.

Sounds prodigious! Usually, semiconductor amplifier manufacturers quote
output intercept, because it's a bigger number and looks better. Is it
really INPUT intercept they're quoting?

GaAs has problems with 1/f noise. Although it's improved over the year froma
noise knee of abt 200MHz 15 -20 years ago, I'd still be suspicous of  160
performance.

Having worked for a semiconductor company for the last 19 years, I am VERY
suspicious of their claims. they are usually the truth - but not 'the whole
truth and nothing but the truth'.

73

Peter G3RZP


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