Other Parts Discussed in Thread: UCC27531, UCC27524, SN74ACT11
Hi,
I faced a problem with a new pasted PCBA. The schematic is as below:
the chip U17 is used to control a MOSFETs Q4 which drive a relay K3。I found it in test that when MAIN-RLY-C-EN signal turn to high level(3.3V),the output MAIN-RLY-C-EN-5V(pin6) rised up to about 3.07V rather than 5V, at the same time the Voltage on pin 14(Vcc, after R136) fall from 5V down to 4.74V.
It seems like broken but I don't get the reason, the chip could handle 25mA continues output current so I don't think it fails for over current, please help me to analysis the failure reason, thanks!