LM76005: Irregular output voltage

Wei Jie Ng

Part Number: LM76005

Hi TI Engineers,

May I know what causes the output of the LM76005 switching regulator to oscillate between 1V to 2V when the output is set to be at 5V and the input voltage is set in the range of (24V to 31V)? At lower input voltages (~5.5V to 10V), it was able to produce the 5V output voltage but it was a 5V sawtooth output instead of a straight 5V output.

Best regards,

Wei Jie Ng.

over 3 years ago

0 Victor Yu over 3 years ago

TI__Expert 4381 points

Hi Wei Jie,

Please upload your schematic if it is convenient. Thanks

BR,

Victor

0 Wei Jie Ng over 3 years ago

Prodigy 30 points

Hi Victor,

Unfortunately, I am not allowed to release any design publicly but I can send it to you via email if it is possible. However, I think that the problem lies in the current PCB layout design as I have another design that uses the same schematic and it works fine.

Regards,
Wei Jie.

0 Victor Yu over 3 years ago in reply to Wei Jie Ng

TI__Expert 4381 points

Hi Wei Jie,

I understand. You can send schematic and layout to victor-yu@ti.com . Let's review the schematic and layout to see what happened.

I also want to confirm with you about load condition and SW pin waveform when output oscillated between 1V to 2V or 5V sawtooth.

BR,

Victor

0 Victor Yu over 3 years ago in reply to Wei Jie Ng

TI__Expert 4381 points

Hi Wei jie，

Since this case is unique and has little meaning for others to learn from ，I will close this thread on E2E. You can reply in this thread or send email to me directly if you have any other questions. Thanks.

BR,

Victor

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LM76005: Irregular output voltage