OPA857: Necessity of AC coupling at input

na na78

Part Number: OPA857
Other Parts Discussed in Thread: TINA-TI

We are considering the connection of APD and OPA857.

Regarding to Figure 44 in the datasheet, we concern that the device would saturate by large DC light.

So, we think it would be better that we apply AC coupling at the input.
Do you see any issue such configuration?
Do you have such a reference design or schematic?

BestRegards

over 8 years ago

0 Rohit Bhat over 8 years ago

TI__Genius 15975 points

Hi,

I think you should be able to AC couple at the input by including a series cap between the APD and inverting input of the OPA857.

Best Regards,
Rohit

0 na na78 over 8 years ago in reply to Rohit Bhat

Guru 16770 points

Hi Rohit

Thank you for reply.
I understood that including series cap at the input is acceptable.

And there is no TI-reference design that has series cap, isn't there?

BestRegards

0 Rohit Bhat over 8 years ago in reply to na na78

TI__Genius 15975 points

Hi,

I don't think we have a TI-reference design that has series cap. I would recommend you to simulate your circuit in TINA-TI to make sure you have a workable solution.

Best Regards,

Rohit

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OPA857: Necessity of AC coupling at input