LMP7721: LMP7721

shanmugapriyan k

Part Number: LMP7721

I am using this LMP7721 schematic as Transimpedance amplifier, so is this circuit is OK for I to V convertor or any other changes need to be done?

over 4 years ago

0 Michael Steffes over 4 years ago

Guru 48395 points

Transimpedance design is all about the source capacitance then your desired gain and bandwidth leading into the required feedback C across the feedback R. So you are missing those C terms to complete the design.

0 shanmugapriyan k over 4 years ago in reply to Michael Steffes

Prodigy 80 points

ok sir now the design is correct ?

0 Michael Steffes over 4 years ago in reply to shanmugapriyan k

Guru 48395 points

No way to say without a source capacitance. And 10u seems crazy high for any transimpedance design. What signal bandwidth do you need. If your current source has no capacitance (odd) then we would just use the op amp parasitic C for design - jumping way ahead, here is a design flow for transimpedance, 4300.Transimpedance design flow using high speed op amps.pptx

0 kai klaas69 over 4 years ago in reply to shanmugapriyan k

Guru 140200 points

Kai

0 Marek Lis over 4 years ago in reply to shanmugapriyan k

TI__Guru 68541 points

As Kai and Micheal said, a junction capacitance, Cj, of the current source (like photodiode) must be known in order to assure TIA circuit stability. Please read the design procedure under following link to optimize the solution:

https://e2e.ti.com/blogs_/archives/b/precisionhub/posts/transimpedance-amplifiers-what-op-amp-bandwidth-do-i-need-part-i?DCMP=hpa-pa-opamp&HQS=hpa-pa-opamp-fb-thehub-20140516-20140507-part1-en

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LMP7721: LMP7721