TPS552882: Dying after a few minutes

Theodore Beauchant

Part Number: TPS552882

Tool/software:

Hi all,

We've built a board using the TPS552882 set for 20V output from a 10 to 36V power supply. The schematics is a copy and paste from the Power Designer tool's output, the components used are the ones recommanded by the tool:

Initialy everything looks good, the output voltage is stable and @20V, however after about 15/20mns the board suddenly stops working, with apparently a short between VOUT and GND. This is at 25V input and about 1.5A constant load.

We've repeated this multiple times on several boards. What could be the reason and how could we fix it?

Many thanks,

Theo

2 months ago

0 Shipeng Cheng 2 months ago

TI__Genius 17450 points

Hi Theo,

Please show us your layout. Thanks.

0 Theodore Beauchant 2 months ago in reply to Shipeng Cheng

Prodigy 105 points

Hi Shipeng,

Here it is:

0 Shipeng Cheng 2 months ago in reply to Theodore Beauchant

TI__Genius 17450 points

Hi Theo,

This layout is bad.

1. All connections is cross-connection, it should be direct connection to make a whole cooper.

2. The gate driver for buck-side high-side FET is DR1H and SW1, this two pin should be connected to high-side FET gate pin and source pin with an individual wire. The SW1 cannot be simply connected to SW1 copper.

3. VIN pin of IC need a cap nearby to GND.

4. VOUT pin and PGND pin need Cout placed very closely. now the ceramic Cout GND pad is very far from PGND pin.

Please copy our EVM layout.

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TPS552882: Dying after a few minutes