CDCDB400: 2.2ohm on VDDR

Roy Hsu

Part Number: CDCDB400

Hi Team,

I'd like to understand why a 2.2ohm resistor is required on VDDR. Is it because VDDR needs to rise slower than VDD?

Thanks!

Roy

+1 Asim Khan over 3 years ago

Hi Roy,

Yes, you are right. Intention is to have VDD core supply established before the VDDR output supply to avoid any unknown state on outputs.

Best,

Asim

0 Roy Hsu over 3 years ago in reply to Asim Khan

Hi Asim,

Is there a minimum required timing difference between VDD and VDDR? Or as long as VDD is established (>3V) faster than VDDR then it's considered OK?

Thanks!

Roy

0 Andrea Vallenilla over 3 years ago in reply to Roy Hsu

Hello Roy,

I believe the ladder is correct, while VDD is established before VDDR you should have no problems. I will double check this for you.

Best,

Andrea

0 Asim Khan over 3 years ago in reply to Roy Hsu

Hi Roy, I don't think there are specific timing requirements it would have been specified in datasheet if there were any.

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