The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Analog Design >> Offset voltage calculation
https://designers-guide.org/forum/YaBB.pl?num=1396888850

Message started by pinkfloyd on Apr 7^th, 2014, 9:40am

Title: Offset voltage calculation
Post by pinkfloyd on Apr 7^th, 2014, 9:40am

I would like to ask the best and the right way to calculate the offset voltage.

It is better to use the OTA in a buffer configuration or to connect the vin+ to the cm and sweep the vin- in open loop configuration?
if we do so, the offset is vout-vin- ??

Thank you

Title: Re: Offset voltage calculation
Post by anil reddy on Apr 11^th, 2014, 4:02am

Hi pinkflyod,

Generally, we may already know the output swing of the OTA, and, it's input will be regulated to a reference voltage through a feedback system.

What i think we should do is that connect the OTA in buffer config, but, place a voltage source in the loop so that we can vary that in order to have required voltage on the input and output.

Thanks
Anil

Title: Re: Offset voltage calculation
Post by aaron_do on Apr 15^th, 2014, 2:19am

IMO the best way to find the offset voltage is the method closest to how your are going to use the amplifier in your application. For example, if you're going to use it in an open loop configuration, then just connect vin+ to vin- (and vcm) and then check vout+-vout-. That's the output offset voltage. The input-referred offset is just that divided by the gain.

Aaron