Way to LTspice model: <
I'd like to abuse them as analog switches because of their low resistance (thermal noise) and low capacitance in a chopper amplifier. Any drawbacks I did not see? The hope is that they still work at VDS = -100mV as a switch.
The ADG819BRTZ has a pretty minimum of charge injection when I adjust VCC & VEE carefully but still too much.
cheers,
Gerhard
The EPC parts have a sort of substrate diode, which conducts if the drain gets about 2 volts below the source, which limits voltage range if used as a series analog switch. The gate also conducts to the source a fair amount, in both directions. A little negative Vds should be OK.
It would be OK as an analog switch if the source signal is stiff and you can tolerate the polarity limits.
Cg-d is microscopic. Cg-s isn't.
The 8002 is a biggish part. Would a smaller one, like EPC2038, work for you? Much less capacitance.
EPC is cool because they have LT Spice example circuits that just work, and don't lie very much.
These parts are basically impossible to connect to for testing, and amazingly EPC doesn't offer adapter boards. We had to make our own to evaluate the parts.
Note that one fet, on the left, is broken. These parts are very fragile, like little delicate blocks of glass.
Am 02.08.19 um 21:12 schrieb John Larkin:
The 2 volts should be no problem. It's on the input side of an amplifier, after all.
I've put it on my order list, together with the 2037 (next larger).
thanks!, Gerhard
Have something to add? Share your thoughts — no account required.
Ask the community — no account required