TS321: How to measure the Input offset voltage of TS321

Eric Lai

Expert 4940 points

Part Number: TS321
Other Parts Discussed in Thread: OPA990

Hi Expert,

The customer is designing the TS321.

And they are asking how to measure the Input offset voltage of TS321.

Pls advice the circuit and method for us.

Thanks.

Best regards,

Eric Lai

Field Application Engineer

Texas Instruments Taiwan Limited

O: +886-2-2175-2582

M: +886-909-262-582

E-Mail:Eric.Lai@ti.com

over 4 years ago

0 Bala Ravi over 4 years ago

TI__Expert 6625 points

Hi Eric,

You can setup a buffer circuit as shown below and power-up the op amp. What you measure at the output is your offset voltage.

Please let us know if you've any further questions.

Regards,

Bala Ravi

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Eric,

don't forget that the input bias currents of TS321 can cause voltage drops across the resistors connected to the inputs of OPAmp which can increase and even dominate the output offset voltage. That's why Bala recommended a test circuit with zero Ohm resistors.

Kai

0 Bala Ravi over 4 years ago in reply to kai klaas69

TI__Expert 6625 points

Hi Eric,

Kai is correct. Please don't add any resistors to the input of the op amp. I will go ahead and close this thread, please let us know if you've any other questions.

Regards,

Bala Ravi

0 Michael Steffes over 4 years ago

Guru 47485 points

Hey Eric,

Not sure why you would use a part that old, it is very low cost - but you might also look at the new OPA990

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TS321: How to measure the Input offset voltage of TS321