millivolt voltage reference

[z9u2k]

Hey,

I'm working on a receiver circuit an I'm in need of a stable millivolt range reference for the final output stage.

The input signal is a modulated 40kHz carrier, much like any IR system. After reception, DC removal (47pF, 1MΩ) and amplification (INA128, x50,000), the threshold needed for a logical '1' is about 100mV.

I'm using a low-power comparator as a final output stage (TLC339).

I'd prefer to avoid further amplification, both from power and space considerations (and to avoid excessive negative bias on the comparator's inputs)

I was thinking on using a precision voltage reference (say, 4.096V), and feed that to a resistive voltage divider.

Question is, will it be stable enough, and whether there's a better way of achieving this low a reference?

Thanks in advance!

 

[keith1200rs]

That is a reasonable way of doing it provided you want a fixed threshold, although I would probably use a 1.22V reference. Make sure you decouple the resistor divider connection to the comparator.

Keith

 

[karesz]

Hi z9u2k,
We have had "extreme" low voltage thresholds of 10...40mV, more as thousand exemplares, their are over 10 years in usage_with no problems of some instabilties... Our was 1.25V reference based too
Btw.; dont forget pls- you will need a very clean & properly bypassed threshold & supply voltage and clean, low impedance/high quality GNDs too...
K.