NE5532: Output Ripple at high level

Chris Peng

Prodigy 560 points

Part Number: NE5532
Other Parts Discussed in Thread: OPA210

Hi team,

My customer met a problem using NE5532P, here is the schematic and waveform about the output.

You can see the output has ripple. Do you have any good advice?

over 2 years ago

0 Chris Peng over 2 years ago

TI__Prodigy 560 points

here is the waveform about on the PIN1

0 Ron Michallick over 2 years ago in reply to Chris Peng

TI__Guru**** 153036 points

Chris,

That's oscillation due to phase lag in the feedback. 390k is a high resistance; so even a small capacitance for input pin and circuit board will create a stability issue. As a test, try soldering a 4pF to 22pF capacitor on top of R225.

To fix without a board change (to add such a cap), try changing feedback resistors from [390k, 100k] to [39k, 10k]

0 Chris Peng over 2 years ago in reply to Ron Michallick

TI__Prodigy 560 points

Hi Ron,

Thanks for your suggestion.

I will tell customer and get the feedback.

This is a old device, customer want to use to control PWM. Is there any suitable device for this EE？

0 Ron Michallick over 2 years ago in reply to Chris Peng

TI__Guru**** 153036 points

Chris,

The circuit is a linear amplifier with a gain near 3.3 ; what is the input signal and desired output signal?

It is not good to leave the other amplifier unconnected.

0 Chris Peng over 2 years ago in reply to Ron Michallick

TI__Prodigy 560 points

Hi Ron,

Thanks for your reply, the customer want to use the amplifier to generate a PWM to control the MOSFET of the power. The input is a MCU output 3.3V signal. I have suggested customer to use the OPA210 to generate the Pulse.

0 Ron Michallick over 2 years ago in reply to Chris Peng

TI__Guru**** 153036 points

Chris,

Other gate drivers here

https://www.ti.com/power-management/gate-drivers/products.html#sort=p1130;asc

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NE5532: Output Ripple at high level