offset voltage in Isolation amplifier

[TeChSaVvY]

I use isolation amplifier (ISO124).
Input signal is +/-10 V analog voltage.
I get considerable offset voltage in the output.
That offset voltage increases with increase in input voltage.
Since its a isolation amplifier, how to nullify offset voltage???

 

[Spehro Pefhany]

On 20 Jan 2005 08:15:36 -0800, the renowned "TeChSaVvY"
<tech.savvy@rediffmail.com> wrote:

I use isolation amplifier (ISO124).
Input signal is +/-10 V analog voltage.
I get considerable offset voltage in the output.
That offset voltage increases with increase in input voltage.

Then it's not offset voltage, it's a gain error (perhaps with an
offset voltage added to it). Unless I misunderstand what you are
saying here.

Since its a isolation amplifier, how to nullify offset voltage???

That part has REALLY crummy DC specs. As much as +/-50mV Vos with
2mV/V change vs the supply, and 200uV/K drift. The gain error is
pretty small. Given that, you can null it at the input or the output
with about equally bad results.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[TeChSaVvY]

With applied 0V input 20 mV is at output. As soon as I increase input
voltage, that 20 mv
offset inreases accordingly. I dont want that 20 mv(offset?) at output.