Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Is it safe to use 1.22V for C3 Vccint?

I'm putting together an Ethernet board that is almost done - but there isn't enough room for a full set of switching power supplies. (I'm trying to keep the board under 13sq.in) I've settled on...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Although a C3 FPGA device doesn't draw more than 1A on Vccint after power-up, it is probably a good idea to design the Vccint rail up to 2-3A for in-rush current. Linear regulators will end up with big heat sinks. I will use TI TPS75003RHLR to provide 3.3V, 2.5V and 1.2V from a 5V rail. I think that 1.2V +-5% should be acceptable in any case as long as it is stable and clean.