[sdiy] How droopy is too droopy in a S & H?

[mark verbos]

I have been seduced by the Analog Devices SMP04 quad sample and hold  
chip. It has 4 independent S&H circuits with built in capacitors, in a  
16 pin chip. I claims a "low droop rate" of 2 mV per Second. Doesn't  
that seem like a lot? How much does a normal sample & hold droop? How  
much does an LF398 with polystyrene caps droop? Is this a waste of  
time and money? The AD684 seems to be about 10 time better, but also  
$50! It's hard to tell because they don't use the same units for  
measuring the specs on all the chips...


Mark