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LMV358: LMV358 amplifier respond quickly

Ping ping

Prodigy 160 points

Part Number: LMV358

We need to quickly switch the amplifier's power supply. But we found that the amplifier output signal will have a delay, about 84ms (secondary amplification)
Do you have an amplifier or other design that can respond quickly?

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Ping,

I think the delay comes from the time constant formed by (R5 + R7) x C6 = 35ms (worst case) and not from the OPAmp itself.

Kai

0 Gerasimos Madalvanos over 4 years ago in reply to kai klaas69

TI__Mastermind 30076 points

After running a quick simulation, Kai (once again) is correct. Running the worst case sim in TINA (file attached) lowering the capacitor value from 1u to 10n greatly speeds up the response.

Best,
Jerry

lmv358_amplifier_response.TSC

0 Ping ping over 4 years ago in reply to Gerasimos Madalvanos

Prodigy 160 points

Hi Jerry,

Thanks~

We will test it.

BR

Ping

0 Ping ping over 4 years ago in reply to Gerasimos Madalvanos

Prodigy 160 points

Hi Jerry,

We changed the capacitance(C6) from 1u to 1n.

Doesn't seem to improve much.

Any other suggestions?

BR,

Ping

0 Ping ping over 4 years ago in reply to Gerasimos Madalvanos

Prodigy 160 points

Hi Jerry,

We changed the capacitance(C6) from 1u to 1n.

Doesn't seem to improve much.

Any other suggestions?

BR,

Ping

0 kai klaas69 over 4 years ago in reply to Ping ping

Guru 140200 points

Hi Ping,

C5 should be decreased as well.

Kai

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

Guru 140200 points

Hi Ping,

does it work now?

Kai

0 Ping ping over 4 years ago in reply to kai klaas69

Prodigy 160 points

Hi Kai,

C5=1n,

Please see the picture below.

You solved our problem and we will check the frequency response,next
anyway. thank you very much

0 kai klaas69 over 4 years ago in reply to Ping ping

Guru 140200 points

You are welcome :-)

Kai