TJA1043 and TJA1044 power supply sequence

[ypchang]

I want to use TJA1043 and TJA1044 as CAN transcivers. The pin VIO is powered by 3.3V, the pin VCC is powered by 5V,  I want to know the power-up sequence between 5V and 3.3V.  whether 5V first ,3.3V second or 3.3V first, 5V second.  Thank you!

[Ben]

Hello

I believe that it does not matter. the VIO feed the bus output section. This side should be protected, as it is possible that the CAN bus side is on power, while the chip circuit PS is off, and it cause no damage.

So actually, if you feed the VIO first, is the same as connecting the can bus while circuit power is off, and it cause no damage.

In my design circuits, the 3V is generated from the 5V, which cause a short delay on the 3V PS. Never had problems with the CAN bus.

Ben