[sdiy] Infinite sample & hold circuit

[rfahl at pdx.edu]

While on that topic...

I came across National's app notes for the LF398 at:

http://www.national.com/apnotes/SampleandHold.html

AN294 has both an example of an extended S&H as well as one for infinite hold 
times.

Romeo



Quoting Yves Usson <Yves.Usson at imag.fr>:

> Hi
> 
> This post is linked to a recent thread about infinite sample & hold.
> I have added to my archive page a scan of an old article that appeared
> in WirelessWorld May, 1976 showing a very simple circuit based on very
> common TTL logic ICs and two OPAs that provides infinite S&H.
> 
> The schematics requires some improvements to increase the step
> accuracy but remains very simple. It's also a good base for
> a low cost quantizer. It probably requires the addition of latch 
> registers
> at the output of the counters, triggered by the comparator and a second 
> resistor ladder
> DAC connected to the output of the latch registers. This way if the 
> actual S&H output
> is taken from this second DAC, the ramp will not appear at the output.
> 
> Check it at :
> 
> http://www-timc.imag.fr/Yves.Usson/personnel/SDIY/archives/index.html
> 
> The title is :Digital sample and Hold (idea for design) by N. MacDonald
> 
> Enjoy
> ---------------------------------------------------------
> Yves Usson
> email : yves.usson at imag.fr
> http://www-timc.imag.fr/Yves.Usson/personnel/SDIY
> 
>