[sdiy] fost precision comparator ?

[René Schmitz]

Hi Jürgen,

A tandem out of a precision amplifier and a more modest comparator 
perhaps? Say a linear preamp with a gain of 10 or so, to make the slope 
that the comparator sees steeper, and the requirements on the comparator 
are relaxed by the gain of the preamp. It should be easier to meet these 
drift specs with an opamp or maybe even a discrete amp .

Cheers,
  René

jhaible at debitel.net wrote:
> Hi
> 
> I'm looking for a comparator for a certain application
> (zero crossing detection; not synth-related), where 
> I need high speed and good precision.
> 
> Requirements are < 200uV drift (offset, hysteresis)
> and < 30ns jitter
> 
> I want to detect the zero crossing of a slow (10kHz)
> signal with constant (1V) amplitude. Propagation
> delay may be longer than 30ns (it probably will be
> longer because of the flat slope / low overdrive),
> and offset may also be higher than 200uV, but
> the *drift* (over 1/2 hour at fairly constant tempertature)
> must be < 200uV, and the *jitter* from one zero crossing
> detection to the next must be <30ns.
> 
> Open collector output required, or an output stage
> that can be supplied with 3V ... 5V.
> Analogue part can be supplied with +/-12V dual supply
> or +5V single supply.
> Must haqndle 0 ... 5V input range without damage,
> +1V ... +4V (operating) common mode voltage.
> 
> Does anybody make comparators like this?
> Maxim and Analog Devices, don't (just talked
> to their application engineers).
> Anybody else making 200uV / 30ns comparators ?
> 
> JH.
> 
> -------------------------------------------------
> debitel.net Webmail
> 

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