Lpc2000

Yes, something similar in that I have powered MSP430s with a red led 
from +5V which gives me 3.2...3.4V. This is of course limited to the 
maximum forward current of the led. It is true that the forward voltage 
drop of diodes varies with current and temperature but this should be 
fine as long as it is adequately decoupled on the 1.8V rail with a small 
tantalum as well. The specs state that you can operate from 1.65V to 
1.95V with an absolute max of 2.5V so worst case max voltage should be 
around 2.1V if the cpu is in reset etc but you can always put a 
resistive load across the rails to maintain a minimum current (increased 
diode forward voltage drop).

Personally, if I really needed to save 50c and design a board to use 
diodes I would still design in an ldo regulator just in case the burn-in 
tests reveal some problems. But for a quick&dirty proto I wouldn't 
hesitate to use the diode approach.



BTW, I have been using torex XC6201 regulators in the tiny sot-25 pack 
as they are inexpensive and readily available (Farnell sell them). How 
has everyone else fared with regulators?

*Peter*


Xtian Xultz wrote:
> Em Ter 25 Abr 2006 12:56, Steve Franks escreveu:
>> So,
>>
>> Closer inspection reveals to me that the Minimum Voltage for the VccIO and
>> VccA pins on the 2103 is 3.0V.  How disappointing - a tiny chip and I have
>> to run a split supply just to get it to boot?  Anyone done the unthinkable
>> and tried to run the whole works off of 1.8V?  And here I wanted to replace
>> all my 8-bit uC's with the 2103 ever after...
>>
>> Steve
>  Its too dangerous to generate 1.8V (more or less) from the 3.3V with two 
> diodes in series?
> Someone tryed this?