STM32F4 USB minimum operating voltage

[gradoj]

Posted on July 21, 2015 at 22:20

I am running the stm32f407 at 1.85V and was wondering if it would be possible to get USB working at this operating voltage. I've pulled up the d+ line to Vbus but cannot get proper enumeration. I believe as long as the differential signal is 100-200mV on the receiving side it should still work. Even with a very short USB cable still no enumeration. Is some kind of level translator or usb signal repeater my only option? Thanks.

[Tesla DeLorean]

Posted on July 21, 2015 at 22:33

The manual for your part says 3.0V minimum VDD, and it can get down to 2.7V with degraded electrical characteristics.

I think these are requirements of the transceiver cell itself, so I don't think you're going to be able to fudge things externally.

[gradoj]

Posted on July 21, 2015 at 22:56

Thanks. I read that minimum voltage in the datasheet as well but they explicitly said 'OTG USB FS' so I thought there may still be a chance.