TPS61289: Vout fail

Tommy Tzeng

Genius 5690 points

Part Number: TPS61289

Tool/software:

Hi Sir,

we can know that out of 9 PCBs tested, only 1 can have output and pass? as attached below,

and since we don't know the reason, could help us check if the schematic is correct?

0 Iden TSAI 6 months ago

0 Fergus He 6 months ago

Hi Tommy,

Thank you for reaching out.

It seems that the device damages in some of the case.

For the schematic,

1. the output capacitors needs connect directly to the VOUT pin, long connection through the fuse?(FBP38 and FBP37) causes high switching spike.

2. the RB43 and CB19 is not needed, they are like snubber circuit and should not at gate side.

3.Please show me your layout or directly send your board to me

4. you could send email to me for quicker communication.

Best Regards,

Fergus

0 Iden TSAI 6 months ago in reply to Fergus He

017138721650.brd Hi Fergus, here is our Layout brd file ,please check the file, thanks

0 Fergus He 6 months ago in reply to Iden TSAI

Hi Iden,

1. as said before, output capacitor is too far from output pin. This causes high switching spike and damage.

2. the MOS is also too far away. the driving speed will be slowed and easy to cause shooting through.

3.It is recommended to use AGND connect to PGND with signal point to prevent switching noise

Please see layout example.

Best Regards,

Fergus

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