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LMR33620-Q1: output ripple is too large(90mV)

Sherry Liang

Genius 10255 points

Part Number: LMR33620-Q1
Other Parts Discussed in Thread: LMR33630-Q1,

Dear team,

When my customer tested the output ripple, and they found that the ripple ups to 90mV, and the schematic is as below. And they also use the shortest ground ring(on the probe) to test it. Is there any wrong about the schematic?

Thanks & Best Regards,

Sherry

over 4 years ago

0 Marshall_Beck over 4 years ago

TI__Mastermind 29750 points

What is the frequency of ripple? 2Mhz?

Can we get the conditions, please:

VIN = ?

VOUT = ?

IOUT = ?

Can you share waveforms?

BOM looks alright, looking at output stage filter. In general, output ripple can be decreased by increasing component values in the output stage driving up BOM cost. We are not going to do that as that defeats the whole purpose of switching at 2Mhz.

The amount of ripple does not make sense to me though, but I need to more information please.

0 Marshall_Beck over 4 years ago in reply to Marshall_Beck

TI__Mastermind 29750 points

Are you still seeing this issue? If not, I will close this thread so it is no longer being monitored.

Please let us know if you need more help.

0 Sherry Liang over 4 years ago in reply to Marshall_Beck

TI__Genius 10255 points

Hi Marshall,

Sorry, this case belongs to LMR33630-Q1, not LMR33620-Q1. Sorry for the mistake. The customer wrote the wrong name...

Thanks for your support!

Thanks & Best Regards,

Sherry

0 Marshall_Beck over 4 years ago in reply to Sherry Liang

TI__Mastermind 29750 points

Steady state output ripple should be similar between the two devices.

Can you share waveforms?

0 Sherry Liang over 4 years ago in reply to Marshall_Beck

TI__Genius 10255 points

Hi Beck,

Thanks for your support!

I will send the waveform tomorrow.

Thanks & Best Regards,

Sherry

0 Ankit Gupta95 over 4 years ago in reply to Sherry Liang

TI__Expert 4555 points

Are you still seeing this issue? If not, I will close this thread so it is no longer being monitored.

Please let us know if you need more help.

Best Regards,

Ankit Gupta

Application Engineer

0 Sherry Liang over 4 years ago in reply to Ankit Gupta95

TI__Genius 10255 points

Hi Ankit,

This issue has been solved. There is a problem with their test methods. Thanks for your support!

Thanks & Best Regards,

Sherry