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Compensated op amp

MSP430-Beginner
Intellectual 660 points
Other Parts Discussed in Thread: OPA353, OPA350

Hi guys,

As mentioned in my last threads, I'm working on designing a circuit for TI to measure the current consumption of MSP430.

My Idea is to connect a shunt in the supply line of the target MSP430 and measure the voltage drop across it. Now I have to take care about the voltage regulation. I think about using an op amp (voltage follower) and connect the shunt inside its feedback loop. The problem is that most op amps are not stable while driving cap load (10uF and 100nF at the input of MSP430). I read several TI articles about compensation of op amps to get stable while driving cap loads.

My question now is: Is there any TI op amp which is already compensated? Do you suggest any compensation lead for any special op amps?

 

I attached my simulation to understand what I'm talking about:

http://www.fileswap.com/dl/WXQLltte/mspbeginner_op_amp.TSC.html

Regards

  • 0
    TI__Guru 64530 points

    MSP430-Beginner,

    OPA350 or OPA353 are capable of driving directly capacitive loads in 10uF range.  Other than that, placing a 10-100ohm resistor in series with the output improves the capacitive load drive of most op amps but may cause DC error when used in conjunction with a resistive load.