TINA/Spice/OPA211-HT: OPA211-HT

Kiran Gopalaiah

Part Number: OPA211-HT
Other Parts Discussed in Thread: TINA-TI, OPA211

Tool/software: TINA-TI or Spice Models

Hi,

Need help to understand ;

1) Want to AC couple signal (Signal has DC offset) to the non inverting amplifier. But facing issues upon AC coupling at the input. Is there is any issue with the Spice model (Not sure)?

OPA211-HT.TSC

over 6 years ago

0 Michael Steffes over 6 years ago

Guru 48395 points

Your terminating resistor is way too high - if you take the max input ib of 125nA times 33Mohm, that is 4.12V,

Reduce it by factor of 10 and raise the input C to 10nF.

0 Kiran Gopalaiah over 6 years ago in reply to Michael Steffes

Intellectual 710 points

Michael Steffes

Thanks for the reply !!

will simulate and get back

Is there any alternate solution too? There is a circuit before the non inverting amplifier which requires high passing. Changing RC values will affect the signal shape.

0 kai klaas69 over 6 years ago in reply to Kiran Gopalaiah

Guru 140200 points

Hi Kiran,

decreasing R1 and increasing C1 by the same factor would leave the corner frequency unchanged. Would this be a solution?

Another remedy would be the use of an OPAmp with a lower input bias current.

Kai

0 Christian Yots over 6 years ago in reply to kai klaas69

TI__Genius 14540 points

Thanks for the inputs Michael and Kai. The apps engineer supporting this device is on travel until Wednesday at which time he might add more to the conversation.

Thanks.

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TINA/Spice/OPA211-HT: OPA211-HT