OPA2197: Unused pin termination

Takuya Terada

Expert 4965 points

Part Number: OPA2197
Other Parts Discussed in Thread: OPA197

Hi team,

My customer would like to know unused pin termination of OPA2197.

they only use single channel.

then could you tell me how to configure unused IN+/- and OUT pin?

I know single channel version OPA197 exist, but they choose OPA2197 because of the cost. (CDP of OPA2197 is more competitive than OPA197)

could you support this?

best regards,
Takuya

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 284570 points

Configure the unused channel as a voltage follower, and tie it to any voltage inside the common-mode range.

Alternatively, use that amplifier as a buffer for the input or output of the other one.

0 Takuya Terada over 2 years ago in reply to Clemens Ladisch

TI__Expert 4965 points

Hi Ladisch,

thank you very much!

I understand.

best regards,
Takuya

0 Raymond Zhang1 over 2 years ago in reply to Takuya Terada

TI__Guru 57221 points

Hi Takuya-san,

As Clemens suggested, please configure unused op amps in a linear operating states, please see the two attached link below.

https://www.ti.com/lit/an/sboa204a/sboa204a.pdf?ts=1650906063422&ref_url=https%253A%252F%252Fwww.google.com%252F

https://e2e.ti.com/blogs_/archives/b/thesignal/posts/the-unused-op-amp-what-to-do

If you have additional questions, please let us know.

Best,

Raymond

+1 Marek Lis over 2 years ago in reply to Raymond Zhang1

TI__Guru 64290 points

Adding to Raymond's comments, the configuration of the unused op amps MUST assure that the input and output voltages of unused channel are within the op amp's linear range - see below. This is especially true in the case of bipolar transistor op amps where operating in the input non-linear region may result in very high input bias current (IB) while operating in the output non-linear region may cause large increase in the quiescent current, IQ.

0 Takuya Terada over 2 years ago in reply to Marek Lis

TI__Expert 4965 points

Hi All,

Thank you for kind support.

I understand.

best regards,
Takuya

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OPA2197: Unused pin termination