LMZ21700: Failure mode exhibited

Paul Joseph

Expert 2775 points

Part Number: LMZ21700

I have observed a failure mode on the LMZ21700SILR regulator, the symptom is as follows:

When the regulator is not powered, the impedance between pin 4 and ground is 4.7 ohms.

When the regulator is powered with 12V, the output voltage is zero.

Can you elaborate on what I am seeing please, thank you.

over 5 years ago

0 Jimmy Hua over 5 years ago

TI__Mastermind 47060 points

Hi Paul,

Can you provide a schematic and pcb layout of your system? The VOS pin is susceptible to noise so the placement of the capacitor(~0.1uF) and layout of the VOS and FB is critical to proper operations.

Regards
Jimmy

0 Paul Joseph over 5 years ago in reply to Jimmy Hua

Expert 2775 points

can you send me your email so I can forward the schematic please.

0 Jimmy Hua over 5 years ago in reply to Paul Joseph

TI__Mastermind 47060 points

Hi Joseph,

You can contact me directly at j-hua@ti.com

Regards,

Jimmy

0 Jimmy Hua over 5 years ago in reply to Jimmy Hua

TI__Mastermind 47060 points

Hi Joseph,

Thank you for sending the schematic and PCB layout. The review was good and I believe the next step is to perform FA on the part to understand the root cause. I will be closing this thread now.

Regards,
Jimmy

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LMZ21700: Failure mode exhibited