LPC1549 Dual Regulator (Digital + Analog)

[lpcware]

Content originally posted in LPCWare by neilt6 on Tue Nov 03 22:01:41 MST 2015
I'd like to use a separate 3.3V regulator for the analog rail of an LPC1549 for noise reasons. However, the datasheet lists the maximum voltage for VDD as being equal to VDDA. Despite both being "3.3V", my regulators have a +-2% output tolerance. Will this be an issue? Thanks.

[lpcware]

Content originally posted in LPCWare by neilt6 on Thu Nov 05 10:09:25 MST 2015
Perfect, thanks!

[lpcware]

Content originally posted in LPCWare by mc on Wed Nov 04 22:53:00 MST 2015
Hi neilt6,
Less than 0.3V margin should be okay.

[lpcware]

Content originally posted in LPCWare by neilt6 on Tue Nov 03 23:41:15 MST 2015
Thanks, but the regulators are fixed. I'm just looking for clarification from NXP as to whether the data sheet means "make them both exactly the same", or "make them both ~3.3V, not 3.3V and 1.8V".

[lpcware]

Content originally posted in LPCWare by briching on Tue Nov 03 22:23:00 MST 2015
If you have adjustable regulators, why not just increase your VDDA regulator by 4% plus some margin (i.e. set to 3.5V) so you don't have to worry about it?  Many pre-set regulators have an adjustment pin, but I guess it depends on the regulator you are using.  One added benefit of this is also that you are pretty sure you can sample all the way to 3.3V with that extra 0.2V of headroom.

Good luck