Re: Low noise IF3601/02 don't meet specs

Fred Bartoli wrote...
> Joe G (Home) wrote,
>> Fred Bartoli wrote,
>>>
>>> they are spec'd at 300pV/rtHz @ 5mA and 100Hz and should get
>>> down near 260pV @ 100kHz.
>>>
>>> Well for the IF3601 and both side of the IF3602 dual, I get
>>> 400pV/rtHz @ 5mA, and the noise PSD is almost flat.
>>
>> In the old days - silicon manufacturers used to publish the
>> test setups to acheive the data *** spec's. ...
>>
>> You can't say the FET doesn't meet spec's until you reproduce
>> the mfg'ers test setup...
>
> Of course I can. I duplicate the working conditions of the
> data*** (5mA/3V) in a test setup that's designed to add not
> more than 2% to the measured noise. Not a big deal really.

Spell it out for us please. At the 100pV noise level it's easy
to mistakenly let the gain-setting components add to the measured
noise. You're claiming under 50pV of test-setup generated noise?
That requires 0.16-ohm resistors, or more likely none at all, like
my HP transistor noise meter, which runs the JFET flat out with a
grounded source, and separately measures its gain, to determine
the divisor required to obtain the narrowband input noise. Tell
us more about your measurement technique.


--
Thanks,
- Win
.

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