Charles, You are absolutely correct. I misread the data sheet. It's interesting that all three LTC1050s behave exactly the same. They have the same lot code number.but I would expect more variation. Live an learn.
Randy On Thu, Apr 27, 2017 at 12:18 PM, Charles Steinmetz <csteinm...@yandex.com> wrote: > Randy wrote: > > but I recently noticed the meter reads -0.08 when the >> input is open on the 1V range and the null switch is on 0.0001 >> This equates to a -8uV reading. >> I believe this is due to the input bias current of the LTC1050 >> * * * >> However, this would imply an 8pA bias current, >> which is much higher than expected. >> > > I am attaching the relevant portion of the LTC1050 datasheet. Note that > at 25C, the 1050 has an input offset current spec of +/- 20pA (both typical > -- max is ~5x worse). I would expect a total input offset of +/- 20uV > (typical) in your circuit. (The 0.5uV typical input offset voltage is not > a significant contributor in this context.) > > Best regards > > Charles > > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.