Lpc2000

Is this for use in an automotive environment?

Is 4.3mA or 50% efficiency when at low currents that big a deal?  What's 
the amp-hour rating of the battery, and how many other devices are using 
it?  How often does it get recharged?

What's your target price range for this setup?

-- Sean

At 07:49 PM 12/1/2005, Guillermo Prandi wrote:
>Hi! I am in trouble trying to find a voltage regulator suitable for my
>project; my project features an LPC2138, a GPS and a radiomodem. When
>idle, it draws around 20-25 mA from the 3.3V source, 500 mA when
>working hard and with short (50 mS) peaks of up to 1.8A. The supply is
>a lead-acid 12V battery (can't change that), and occasionally, when the
>battery is charging, the input voltage will rise up to ~20V. The
>problem is the regulator efficiency. We were going for the LM2676-3.3V
>switching regulator, because it seemed simple and in range, but two
>things made it a poor choice: it draws about 4.3 mA from the battery
>just for its own supply, and its efficiency when the load is in the 20-
>25 mA range is awful (less than 50%, not counting Iquiescent). I looked
>everywhere but I couldn't find any other switcher with better
>performance in these conditions (12V in, 3.3V out, 20-25 mA average
>load, but >1.5A capability). And there's a catch! The radiomodem is
>extremely sensitive to VCC getting lower than 3.3V especially in the
>current peaks! Also, it should be relatively easy to find in ~400
>quantities (i.e., Digikey, Mouser or your suggestion).
>
>Any ideas?
>
>Guille