CDC3RL02: Can I tie VLDO to an external 1.8V supply?

Eric Steimle

Part Number: CDC3RL02

We made a mistake and tied the clock request lines to VLDO thinking it was always on. Now I see you're not supposed to do that. Is it possible to power VLDO from an external 1.8V supply to force it to turn on? I tried just tying a 10k resistor from VLDO to another 1.8V supply but that didn't work. Long term we'll change the board. I'm just trying to get it to work in the short term.

Thank you

over 5 years ago

0 Eric Steimle over 5 years ago

Expert 2240 points

slight update, turns out you "can". Now the question is should I do this :) ?

0 Alan O over 5 years ago in reply to Eric Steimle

TI__Mastermind 32575 points

I think it should be OK to bootstrap the VLDO output as you described as long as the other 1.8V supply does not draw a lot of current (indicating some parasitic current path). You might consider using a series resistor to limit current. I wouldn't recommend this for the final design, but it sounds like you will be fixing this in the next revision.

Alan

Clock & timing

Clock & timing forum

CDC3RL02: Can I tie VLDO to an external 1.8V supply?