Other Parts Discussed in Thread: TPS2663
Dear TI experts could you please give some ideas to investigate LM76005 breakdown?
1. The schematics is like Webench-recommended except BIAS input is left floating. Output voltage is set to 24.9V. The same breakdown was observed on 9V output setting on the same board so likely it doesn't relay on output voltage setting.
2. Breakdown lies in IC burn-in at Vin pins (please have a look at the attached photo) when scheme have just connected to 50V output of lab supply or low-impedance output (we've get the same on LiPo 51V battery output). It looks like 'latch effect'. After that, input is opened (but input stage seems to be burned out totally), and output is shorted.
3. We have 3 boards already with totally the same effect.
4. For 24.9V output 22uH Bourns SRP1265A inductor was used.