David Wrote

> I am looking for some Voltage regulator IC's for a PIC application that is
> to be installed in a vehicle.
>
> The unit must be able to be run in a 12V or 24V vehicle.
>
> so, Vin = 10V to 30V, Imax = 1.5A, (maybe a big brother to LM2940.
>
> Also, a device for +12V in, +/- 5V out at 100mA.
>
A 30V max tolerance will see the Vreg die a horrible death in no
time flat, especially in a 24 volt vehicle.
More like 60V tolerance for 100mS at a time.

1.5 Amps from a 24 volt source to 5 volt out is a lot of heat/power
to waste, around 30 watts. I would seriously look at a switching
supply such as MAX 746, a 2AMP 45 V input switching Reg.
Its not cheap but is works very well, is easy to pick components
for, is 90% efficient and is all but indestructible as long as you do
not exceed 45 volts into it. It will die at 46 to 47 volts in, so an input
protection tranzorb or big zener would be a good idea.
There is a data sheet at www.maxim-ic.com

Maxim have a large number of switchers for the +/- 5 volts
@100mA requirement as well.

_____________________________

Lance Allen
Technical Officer
Uni of Auckland
Psych Dept
New Zealand

www.psych.auckland.ac.nz

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