Hi,
I am working with the LM8365 and wanted to know if the input voltage goes to zero, does the output sink any current?
It is being used as an undervoltage detector and seems that if:
Vin = 0, no alarm is signaled (output is pulled up)
Vin <2.7V but still high enough to power the device, alarm is signaled (output goes to zero)
Is this the expected behavior?
Best regards,
Caleb Overbay
HI Caleb,
If VIN goes to zero, the uC should turn off automatically unless you have some big caps that are charged up to Vcc and cause the delay in turning off. LM8365 main purpose is to continuously monitor the VIN and as it droops down to VDEL threshold, the RESET will be triggered with appropriate delay based on your delay cap value. If VIN completely shuts Off and you have a delay cap, the LM8365 will not have change to trigger RESET because RESET is active low and will drop automatically as VIN drops to zero.
Please see the timing diagram below:
Can you share some more design details (Sch) ?
Hope this helps
Hi Kaisar,
Thanks for the info. The Vin is being fed from a different supply than the pullup resistor on the RESET line. After looking at the datasheet, it looks like, if Vin to the LM8365 goes to 0, that there is nothing there to bias the FET at the output leaving it open drain instead of pulled to ground. This is why I am seeing RESET as high. Can you confirm this? Thanks again for your help!
Best regards,
Caleb Overbay
