STM32-H407 Power Supply also for external device.

[pantelis]

Hello!

I am new to the forum! So nice to meet you! I would like to make a quick question about a PCB I am designing.

Specifically I design a PCB of a 3-phase inverter for the drive of a PMSM. I intend to connect this PCB with the STM32-H407 board, in order to control the inverter.

However I have a little trouble regarding a power supply issue. Specifically I want to use a Quad Differential Line Receiver for the QEI signals that come from the motor and before sending them to the μC.

On my PCB I already have a 5V Power supply but in order to be able to send these signals to STM32F407, I need to use a 3.3V supply source, otherwise the digital output signals of the IC would be 5V.

Do you think I could use the supply from the development board? The supply current gets maximum value of 3.5mA according to the receivers output, which I consider to be not that large, compared to the total 0.5Amp the the board's supply can give.

I don't know if active links are allowed, therefore I didn't put any. However the name of the Receiver is  MAX3096.

Thank you in advance for your help.

Regards,
Pantelis

[Lurch]

The board has power to spare. The step-down converter insures you have enough current at 3,3V