Voltage comparators 0.1volts or better

[Screech]

can they compare a small voltage differences of 0.1 volts or smaller ?
ie. can they compare 0.4 and 0.5volts?


LM311,LM319,whats their smallest difference they can compare?
Can anyone recommend one that could compare 0.1volts or better?
I've looked up some spec sheets, but could'nt make out much of them.

Thanks again

 

[Nigel Goodwin]

can they compare a small voltage differences of 0.1 volts or smaller ?
ie. can they compare 0.4 and 0.5volts?

Yes - but you could always amplify the levels if you needed to.

 

[Roff]

The key specs are maximum input offset voltage and minimum voltage gain. For LM311, the max offset voltage is 7.5 millivolts, and the minimum gain is 40,000. The gain spec means that, in order to get a full 5 volt swing on the output, the differential input voltage needs to be at least (5/40,000) 0.125mv. The offset voltage spec means that, if the differential input voltage is less than +/-7.5mv, the output could be either high or low for any given unit. The two graphs labeled "response Time for Various Input Overdrives" have additional info. They assume zero offset, so, for example, the 2 millivolt overdrive curve means that if you overdrive the input 2mv past the offset voltage (which could be +/- 7.5mv) of your particular unit, it will respond as shown in the graphs.

 

[Screech]

Great answers.
I read your answers some 10 times, word for word, before I could make sense of it. I'm much wiser now.

The LM311 will work great then.
Thanks very much