My board was designed with BF524. BF524 operates as USB device. The circuit is coped below and the same as evaluation B/D.
Occasionally, the following situation happens while operating.
- VBUS from usb host keeps supplied to USBVBUS of BF524 although board power(USBVDD1 and USBVDD2) is off.
After the situation, USB block of BF524 seems to become defective(broken). I wonder if BF524 USB block is possibly defective when USBVBUS is powered and USBVDDx is not powered. So should I revise my hardware to avoid the situation?