Lpc2000

Is 50mA enough for the 1.8V on the LPC chips? The LPC2114 data sheet 
says 30mA but what is the maximum? I remember somebody on this group 
saying it was always more than 30mA.

Any comments? Thanks, Gus

Gus wrote:

>Is 50mA enough for the 1.8V on the LPC chips? The LPC2114 data sheet 
>says 30mA but what is the maximum? I remember somebody on this group 
>saying it was always more than 30mA.
>
>  
>
Well, you do have surge currents while the device is "leaping" into 
doing work..  In that case, usually a low ESR capacitor such as tantalum 
or a good quality ceramic device located "near" the 1.8v supply will 
handle surge currents.  Something between 0.1uf and 1uf is a good 
value.  I have several 10uf tantalums (3) on my dual LPC2xxx board, 
these are located at "busy" current nodes, also I have bypassed (cap 
located close to the device across the supply line) all devices with 
0.1uf caps.

Generally, you do the best guess, then look at the initial prototype 
board with a scope to see if there are any hot-spots which need a local 
current store / dump (capacitor).


TomW



>Any comments? Thanks, Gus
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-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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Gus,

the tested limit is 70 mAs to be considered a fail.  Running at 60 MHz 
from SRAM with all peripherals active and V18 towards the upper end 
(1.95V) it is possible to exceed 50 mAs but we never measured anything 
above 60 mAs.

Robert

--- In lpc2000@yahoogroups.com, "Gus" <gus_is_working@y...> wrote:

>
> Is 50mA enough for the 1.8V on the LPC chips? The LPC2114 data sheet 
> says 30mA but what is the maximum? I remember somebody on this group 
> saying it was always more than 30mA.
> 
> Any comments? Thanks, Gus
>