Failure Analysis of TI TPS767D301 Voltage Regulator

Gideon Analytical Laboratories received one TI TPS767D301 dual-output low-dropout voltage regulator with a ground to reset short The TI TPS767D301 offers a transient response, low dropout voltages, and dual outputs. It is designed primarily for DSP applications. It features extended temperature performance from 55 to 125 degrees Celsius, drop out voltage typically 350 mV at 1 A, and enhanced product-change notification. The goal was to determine why these TI TPS767D301 voltage regulators were failing, paying special attention to the ground to reset short.

Failure analysis was conducted on the TI TPS767D301 voltage regulator. After conformal coating removal, the part number was revealed. X-rays were taken while still mounted to the PCB. It was then decapsulated. There was irregular solder below the die. Micrographs of the failure sites were taken. It did not appear to be a typical EOS with melted metal or an ESD event with blown oxides. This appeared to likely be a manufacturing anomaly rather than any application induced phenomena.

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Outputs of the 2nd regulator, a fixed 3.3V out on pin 17 apparently defective

Outputs of the 2nd regulator, a fixed 3.3V out on pin 17 apparently defective

Spots do not appear to be typical EOS or an ESD event

Spots do not appear to be typical EOS or an ESD event

X ray of failed device, irregular solder below die

X ray of failed device, irregular solder below die

Conformal Coating removed, part number revealed

Conformal Coating removed, part number revealed

Skimpy solder

Skimpy solder

2nd regulator. Failure site is inside the yellow ring

2nd regulator. Failure site is inside the yellow ring

The adjustable 1st regulator version in the package

The adjustable 1st regulator version in the package