OPA375: Low bias

Kai Hsiao

Guru 12675 points

Part Number: OPA375

HI Sir

My application is Laser diode for fiber

May I know R3 and C2's function ,have any document could be refereed ?

over 6 years ago

0 Paul Goedeke over 6 years ago

TI__Mastermind 30600 points

Hi Kai,

This circuit is a non-inverting amplifier with C1 serving as a filter element. Assuming that you are driving the laser diode with the output of this circuit, C2 could represent the capacitance of the laser diode and R3 could be an isolation resistor to help with stability. I recommend taking a look at TI Precisions Labs, section 10 on stability.

Video 10.5 directly discusses using an isolation resistor: training.ti.com/ti-precision-labs-op-amps-stability-5

If you have more specific questions about your application, we may be able to help you further but this is a pretty generic circuit.

Best,
Paul

0 Kai Hsiao over 6 years ago in reply to Paul Goedeke

Guru 12675 points

Hi Paul

If I use inverting amp circuit ,should I add this R3 and C2 on my schematic ?

Thanks

0 Paul Goedeke over 6 years ago in reply to Kai Hsiao

TI__Mastermind 30600 points

Same advice applies for the inverting amplifier. Having the output RC filter is not generally recommended and will need to be properly compensated.

It would be helpful if you had a schematic of your own for us to look at so that we understand the design.

Best,
Paul

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OPA375: Low bias