> Message: 5
> Date: Mon, 14 Apr 2008 16:41:54 +1200
> From: Apptech <apptech@paradise.net.nz>
> Subject: Re: [EE] LM2940 Question
> To: "Microcontroller discussion list - Public." <piclist@mit.edu>
> Message-ID: <011901c89de9$dfbcc3d0$e701a8c0@y2k>
> Content-Type: text/plain; format=flowed; charset=iso-8859-1;
> 	reply-type=original
> 
> >> >  Why not use a 7805/TO220 in the automotive
> >> > environment? All you need to
> >> >  do is install the
> >> >  recommended caps, but also install a TVS or varistor
> >> > on the input to
> >> >  protect from ESD spiking.
> >> >  The LM7805 is very forgiving, and not as cranky as the
> >> > LM2940. I use 'em
> >> >  all over the place.
> 
> 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.
> 
> 
> 
>             Russell


I've used the LM2940S in automotive applications, they are very robust. They
do have a requirement for the ESR of the output cap but it is something like
0.1R to 2R, dependent on current drawn. This is actually quite a wide range
but you should consider the parallel effect of any other large caps on the
board. I generally use tants for the output cap.

Cheers
James


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist