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

[Veronica Merryfield]

Not sure if this will help, but figures out there (chips to discretes)  
range from 1mv/s to 5mv/s in our field of interest.

If this is for an analogue synth to hold the note, then often it needs  
to hold it once a key is realeased, so unless you have extremely long  
release times, it will be ok. If this is hold a note for a long time,  
then droop is going to be an issue - I could not find anything much  
better than 1mv/s in an analogue solution. However, a pic like a/d->d/ 
a will hold for as long as it is powered providing the resolution of  
the converters is acceptable.

What's the application?

Veronica

On 26-Jan-09, at 12:51 PM, Andre Majorel wrote:

> On 2009-01-26 13:08 -0500, mark verbos wrote:
>
>> 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?
>
> Haven't timed my Oakley S&H but 2 mV/s is about 2.4 cents/s. That
> sounds a bit much.
>
> -- 
> André Majorel <URL:http://www.teaser.fr/~amajorel/>
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