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L5973D step down regulator

Question asked by Paweł Flisikowski on Oct 20, 2017


I'm repairing an audio power amplifiers from a top model manufacturer like Harman-Kardon, Dynaudio, Bose from cars. And in almost all of models I faceing up with broken regulator L5973. The failure is that the voltage on the output increases to 4-5V causing a damage in connected DSP chips. This is standard application from page 9 from the ST datasheet. Input is 12V output is 3,3V.

What can be a root cause of this behaviour? When I replace for new IC it is working in next coulpe of months ok and again fails.

Maybe somebody had this case and could share some ideas