TPS62040 Excessive Input Leakage Current

Stephen Kim

Other Parts Discussed in Thread: TPS62046

A customer has done board testing in temp oven with 1.5uH inductor and seen the failures.

At that time, they used a long input power cable that caused input voltage spike to go over 7V ( abs max of the part is 7V.)

We suggested to lower the input voltage spike and change it to 4.7uH inductor.

They rerun the test with the changes and found no issues.

Is the spike or 1.5uH inductor cause of the problme?

over 14 years ago

0 Jeff F over 14 years ago

TI__Guru*** 146655 points

Is "INPUT" the VIN pin or the SW pin?

0 Stephen Kim over 14 years ago in reply to Jeff F

TI__Prodigy 620 points

It is vin pin.

Nominal input voltage is 5V.

Vout = 3.3V

Iout is 600mA.

The actual part number is TPS62046.

0 Jeff F over 14 years ago in reply to Stephen Kim

TI__Guru*** 146655 points

Most likely it was the 7V+ spike on Vin. The smaller inductor would have caused higher di/dt rates for the inductor and therefore switch currents. The current sensing circuitry may not have measured the current accurately thereby potentially allowing higher than rated current levels in the part. But, since the output current is only half the maximum value, I don't think higher di/dt currents at half max rated values would have damaged the part.

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TPS62040 Excessive Input Leakage Current