Hi
I again took a buffer (voltage follower) formed of a
generic R2R-IO,
unity gain-stable CMOS opamp (MIC7300, TLV9001...). Those supply (or
sink) 40 mA and more. But the max. output current depends on the output
voltage, so, if we want to continue with that approach, I'd likely add a
BJT current helper stage behind the opamp (BJT collector on 5V). We have
almost no dynamic demands on that opamp, so disregarding any phase
errors we introduce by driving large capacitive and resistive loads, it
would work w/o a BJT, but let's see...
Heh, I just prototyped something last weekend for another project with
controlled VIO using a mcp6001 and a N-mos pass transistor. ( It sure
doesn't have the lower drop-out configuration but I think it's more
stable that way ).
So I don't see an external ref voltage input on
that PCB... maybe your
use case would explain your needs here! ;)
I don't see the need for a external vref input.
VDDANA is fine.
Cheers,
Sylvain