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TPS631010: internal failure causes short circuit

Part Number: TPS631010


We use the TPS631010YBGR as a buck converter with 5V applied on the input, and the output configured as 3V3.

The normal load during use is around 30mA, while the maximum peak load can go up to 160mA.

On startup of the system behind the DC/DC around 1A of inrush current occurs (during ⋍100µs).

The used inductor (IHHP0805ZHER1R0M01) has a 3.3A saturation current rating.

We have tested five different boards with the TPS631010 used as in the schematic below with the following results:

The DC/DC sometimes fails and the 5V applied at the input is directly connected to the 3V3 output rail or creates a short from the input to the GND.

Replacing the failed TPS631010 with a new IC does create a stable 3V3 at the output again, so only the TPS631010 broke down.

The failure happend with some boards on startup, and sometimes after prolonged use (>24h).

The 5V applied at the input is from a stable power supply with a low ripple (<10mV).

Do you have any ideas to where the issue of the DC/DC failure could originate from?

  • Hi matthias,

    Thanks for using TI's device.

    Most possibility, the damaged device are out of ABS specS. Altough the input voltage is stable 5V, the voltage at Pin and LX1 are higher because there are some spikes.

    May be we can find that PVin or LX1 are shorted to GND at the damaged device

    The amplitude of the spike is decided by layout and load current. During start-up the peak of inductor should be higher one, it is more dagerous during start-up.

    For layout,  it is has great help to reduce spikes. please take the layout example in DS as ref.