LM61495-Q1: When the LM61495 input is powered down, the output voltage has a jitter problem

Amelie Zheng

Part Number: LM61495-Q1
Other Parts Discussed in Thread: LM61495

Hi team,

When the LM61495 input is powered down, the output voltage has a jitter problem, as shown in the figure below.
Customer is testing with a electronic load : OK with a load below 4A, it will jitter with a load above 5A.
The demo board also has this problem.
There is nothing adjustable on the SCH, please help to see where the problem is?

Fsw is 400KHz and the output inductor is changing to 2.2uH

Any advice?

over 2 years ago

0 Jimmy Hua over 2 years ago

TI__Mastermind 47060 points

Hi,

Have you confirmed that this issue was observed on the EVM as well?
I saw your comment "The demo board also has this problem." and I just want to reconfirm that this is correct.

Regards,

Jimmy

0 Jimmy Hua over 2 years ago in reply to Jimmy Hua

TI__Mastermind 47060 points

Can you provide VIN,VOUT, SW and IOUT waveforms? It will help me understand what is happening to the device during shutoff.

0 Amelie Zheng over 2 years ago in reply to Jimmy Hua

TI__Genius 10865 points

yes. because I also apply EVM for customer

0 Jimmy Hua over 2 years ago in reply to Amelie Zheng

TI__Mastermind 47060 points

Hi,

Can you please provide more waveforms as requested previously?

I will review the schematic and provide feedback if I see anything out of ordinary.

Regards,

Jimmy

0 Jimmy Hua over 2 years ago in reply to Jimmy Hua

TI__Mastermind 47060 points

Hi,

The components in the schematic look okay.

Input/output capacitance and Rff/Cff look okay.

Please provide SW node waveform during shutdown for me to evaluate the electrical behavior of the demo board.

Regards,

Jimmy

0 Jimmy Hua over 2 years ago in reply to Jimmy Hua

TI__Mastermind 47060 points

Hi,

This troubleshooting has been pulled offline to the appropriate apps support member.

Because of this, I will close this thread for now to consolidate troubleshooting efforts.

Thank you for using the E2E forum.

Regards,

Jimmy

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LM61495-Q1: When the LM61495 input is powered down, the output voltage has a jitter problem