Wiring up a 3.3v voltage regulator???

[Slats]

Guys (and particularly Andy),

I am interested in using this product

http://www.dimensionengineering.com/datasheets/DE-SW0XX.pdf

or this one:

http://www.dimensionengineering.com/datasheets/DE-SWADJ.pdf

What I want to do is step down an input voltage of around 6v to 12v to around 3v - where this voltage will power a small radar unit.

What I want to know is how do I wire it up.
The unit has three pin terminals. These are Voltage IN / GRND / Voltage Out.
I am unsure about this.


My thinking is that:
Voltage IN = the positive V and wire from the voltage input
Voltage OUT = the positive V and wire to my radar DC motor
GRND = both the negative wire from the input voltage and the negative wire to the DC motor

Is that correct?

If not how do I hook it up?

Thanks

John

[Subculture]

That's correct. Although to be honest a switchmode regulator is somewhat overkill for that application- such a motor should draw under a watt, and would be easily dealt with using a 3.3 volt linear regulator, at a fraction of the cost (e.g. under a quid).

I would choose a low dropout voltage regulator, and run it off the receiver bus, which is already regulated down to 5 volts, so the linear regualtor only has to drop 1.7 volts. Efficiency wise it will be on par with a switching regulator.

You need to wire in a couple of bypass capacitors on two of the terminal legs- quick and easy job, but that is all.

[Slats]

Ok thanks
I was getting confused with only one GRD. I thought each voltage (input and out) need a separate negative wire.
Thanks
J

[Subculture]

Grounds should always be commoned, else you run the risk of ground loops, which cause all kinds of fun.

[Slats]

Thanks Andy - really valuable information - I have learned something.

J