OPA859: OPA859 design check..

Peter Tseng

Part Number: OPA859

Tool/software:

Hi Team,

Please help to check design below is OK or not?

Customer wants to design a noninverting amplifier, and the TIA_OUT signal is 0~1.4V with 100KHz, the output is 0~3.3V

Any modification suggestion is appreciated.

Thanks.

0 Peter Tseng 26 days ago

Hi Sir,

Any comments for the question?

+1 Sima Jalaleddine 25 days ago in reply to Peter Tseng

Hello Peter,

We apologize for missing your thread. There are no issues in schematic. However, two comments:

Datasheet recommends to set feedback value to 150 ohms and adjust Rg for gain: “When configuring the OPA859 as a noninverting amplifier in gains less than 3 V/V, set RF = 150 Ω. When configuring the OPA859 as a noninverting amplifier in gains of 4 V/V and greater, set RF = 453 Ω.”
If max input is 1.4V, then max output voltage is 4.2V due to 3V/V gain configuration. Amplifier will be saturated at 4.1V. To avoid, can lower gain to 2V/V or 2.9V/V.

Thank you,

Sima

Amplifiers forum