Tool/software:

Hello,

I have got samples from summer 2024( first samples I think) and some chip won't start.

48V input, 200uF output capacitor, dv/dt=0.6V/ms.

Some chip tries to start and the output stay around 10V, increasing very slowly during 5sec (datasheet limit is 5sec) then a fault is asserted. The current is around 200mA (no hitting I start_up=0.56A), TEMP pin doesn't increase, indicating 25C(amb).  It looks likes the chip tries to regulated the dv/dt in output but it's instable and it stays stuck.

I tried to increase/decrease a lot the dv/dt, no change. if I use 30uF output capacitor ,it's working fine.

After replacing the chip, it's working fine with 200uF output capacitor ( my boards were assembled by a pcb manufacturer, so it's not manual assembly which could have broken the chip due to too much heat).

Are you aware of any design problem for the TPS1685?

Regards,

Clement