Questions for suitable TIA devices recommendation

Jacky Wang(QD)

Other Parts Discussed in Thread: OPA857, OPA855

Hi Experts,

Our customer has below TIA requirements based on below requirements, can you help to check if we have suitable TIA devices to meet it? Thanks a lot!

Application Block Diagram and TIA requirements:

over 7 years ago

0 Hasan Babiker31 over 7 years ago

TI__Genius 15605 points

Hello Jacky,

Can you clarify more on the desired gain control? Currently the only amplifier with a selectable feedback resistance is the OPA857, which can't achieve the 2GHz bandwidth that you specified.

Best,
Hasan Babiker

0 Jacky Wang(QD) over 7 years ago in reply to Hasan Babiker31

TI__Genius 11690 points

Hi Hasan,

Thanks for the reply. Please help to focus on the first TIA stage which needs fixed gain is OK. For the second stage variable gain control op-amp solutions, customer will have solutions.

Thanks a lot!

0 Hasan Babiker31 over 7 years ago in reply to Jacky Wang(QD)

TI__Genius 15605 points

Hello Jacky,

What is the desired transimpedance gain of the first stage? Also what is the capacitance of the photodiode?

Best,
Hasan Babiker

0 Jacky Wang(QD) over 7 years ago in reply to Hasan Babiker31

TI__Genius 11690 points

Hi Hasan,
The capacitance of the APD diode is 0.4pF typical, and for the gain of TIA stage, no special requirements for the gain range, as they will have the post stage to amplify again.
Thanks.

0 Hasan Babiker31 over 7 years ago in reply to Jacky Wang(QD)

TI__Genius 15605 points

Hello Jacky,

Currently none of our devices are suited to meet a bandwidth of 2GHz for a TIA application. The OPA855 would be the closest option, possibly providing a bandwidth of around 1GHz.

Best,

Hasan Babiker

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Questions for suitable TIA devices recommendation