LTC3256 watchdog issue

Hello,

Does the sudden reset constantly occurs?

Regards,

Nino

Hi Nino,

Thanks for your answer.

Yes, after the first reset shown in my previous screenshot, reset constantly occurs.

As you can see in the screenshot below, reset occurs after each WDI falling edge ... I'm still investigating why LTC3256 resets after few minutes

Have a nice day

Julien

Hi Julien,

I do not see the problem with the schematic or waveforms. I did come up with different upper and lower limits, 7.5ms and 0.295ms which matched more of the graph in the datasheet. But that should still work with the 900Hz clock. 

If the WDI input is grounded to disable the input does the RST still go low? Maybe there is noise coupling in on the RSTI input. 

Hi Marty,

Thanks for your help,

I tried to disable WDI and now RST stay high (test performed during 1 hour).

It seems there is a problem with whatchdog feature on LTC3256. I also tried to change frequency on WDI input from 200Hz to 1500Hz, RST still go low after few minutes (around 2 minutes). With WDI input outside whatchdog window (2000Hz for example), RST occurs immediatly.

regards,

Julien