>>  The LM293x family are intended for automotive use. I'm 
>> not
>>  sure whether or not ou would consider them "cranky" in 
>> the
>>  same manner as the LM2940 but the experience of a friend 
>> who
>>  specialises in in-vehicle computer telemetry and 
>> metering
>>  systems is that they work very well.

> Er...maybe I made a mistake. I thought the LM2940 was part 
> of the same
> family. What part in the LM293x family should I be looking 
> at to get a
> 5V positive regulator? LM2936 seems to be ok. I'm finding 
> National's
> flash/Java whatever it is website to be supremely 
> unhelpful.

They do seem to be similarly described :-).
There's no certainty of how similar parts in contiguous 
numbering ranges are without poring through data sheets, and 
then guessing.

The LM2936 is ultra low power, low dropout and nice to use 
and ultra expensive. It is limited to 50 mA max output. From 
several years ago memory I thing the Iq is about 14 uA 
typical, which is why I used to use it in a power-always-on 
design.

LM2930 is 1A version.
Iq is far worse than for 2936 - but MUCH cheaper.

The LM294x series says "designed also for vehicular ..." and 
the LM293c says "designed originally for vehicular ..." but 
that MAY just reflect their original inception dates.

    LM2930    http://www.national.com/ds/LM/LM2930.pdf

    LM2940    http://www.national.com/ds/LM/LM2940.pdf

The LM2930 SEEMS to have more strictly auto-environment 
words in its blurb.

Features
Reverse battery protection
40V load dump protection

Plus

Internal short circuit current limit
Internal thermal overload protection
Mirror-image insertion protection
Input-output differential less than 0.6V

Cout needs to be >= 10 uF.
Use a solid aluminium :-)





        Russell McMahon

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