Matt Ormsby wrote:
>
> I ran into a small problem with a circuit and was hoping for some help.  I
> have an output from another device of which runs 1.1 volts on to 0 volts
> off.  I tried to run this into a regular npn 2222a and it would not source
> enough current to drive the transistor to the on state.  So I went to an
> n-channel mpf102 fet and had better success but still I can not turn that
> thing on all the way.  So I started thinking about a 741 op amp and played
> with that with success.  This is the problem.  I don't have room for a -
> supply on this board.  Does anyone have a way that I can get this output up
> to a good ttl level with a meg ohm input resistance or so?
> Thank you for any and all help.
>
> Matthew Ormsby
> Matt@epfsc.com
> http://www.cyberport.com/~mormsby
I would use a sensitive optocoupler they use ir led's and will work well
at 1.1v your output can swing practically rail to rail.
if you have the current => 3ma. they also use little space.