[time-nuts] time-nuts Digest, Vol 91, Issue 168
lists at lazygranch.com
Wed Feb 29 03:16:15 UTC 2012
That is a good part, but generally for higher frequency circuita, the
BF862 is used.
Note the lower capacitance. Noise is higher, but you can parallel the
devices. They are quite cheap since it is a common part.
You will note LTC plops them in a lot of app notes. Sometimes as
bootstraps in TIAs, other times to pull extra current out of the op amp
output to linearize it.
Usually you can get a strip of the on ebay for pocket change, but I
don't see any there at the moment.
On 2/28/2012 3:06 PM, Bill Fuqua wrote:
> At what frequency do you have 1 nv per square root Hz with opamp and
> what opamp ?
> The 1/f region is the killer and if it is a low frequency shift in the
> effectively changing the threshold then you have to be concerned about the
> 1/f region.
> Discrete embedded JFETs have the best 1/f of all such as the IF3601.
> Go to www.interfet.com
> Bill wa4lav
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