+/- supply frm single chip

i m doin 1 project where i need 2 supply power 2 ADC AD677 ... i need

+/- 5/12 volts..i want this all frm single chip instead of using 7805,7812,7905 & 7912.

can u help me

Reply to
aaryaluv
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What's the big deal about using '1 chip' only ?

Graham

Reply to
Eeyore

--
He asked for help, not asinine bullshit.
Reply to
John Fields

There are some single chip twin rail ICs but they're quite expensive and not widely available. I'm trying to find out the underlying reason for the question so as to be able to give a decent answer.

Graham

Reply to
Eeyore

What's Vin?

Cheers

PeteS

Reply to
PeteS

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The big deal is, that\'s what he wants, and a decent answer, you rude
piece of shit, might have been: "I don\'t think what you want is
 Click to see the full signature
Reply to
John Fields

question

Still doesn't answer why he's so keen t use a single chip though. Really also need to know what the proposed power source is. As in is it necessasry to creat a 'false ground'.

To be honest *any* further information at all would be useful.

Got out the wrong side of bad today did you btw ?

Graham

p.s. what's your feeling about the terror con being foisted on the public ?

Reply to
Eeyore

In order to get a more helpful answer, you have to tell what you've got as an input voltage, and how much power you need for the other stuff.

I'm also wondering where your requirement for -5VDC is coming from -- the AD677 only requires a +5 for logic and a +/-12V for the analog side.

Apart from all that, no single IC exists that can do what you want. Linear regulators are cheap and efficient -- splurge a little. But if you want maximum simplicity or absolute minimum space, try purchasing a small AC-to-DC converter which will give you the three voltages.

And please hold off on the text lingo unless you're kidnapped and are being confined in a car trunk. It gives the impression you can't even be bothered to express yourself clearly. That's not a good impression to give if you're asking for someone to craft a ldetailed, cogent answer.

Good luck Chris

Reply to
Chris

Vin is 20 V...and i hv been told 2 use a single chip...i can use the above mentioned chips..but i hv 2 use a single chip which is a cheap 1 too...

Reply to
aaryaluv

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So for a Vin of 20V you _have_ to get +5V, -5V, +12V, and -12V all
out of the same chip?
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Reply to
John Fields

AC or DC ? With or without centre tap ?

There is no cheap single chip solution to your problem I'm afraid.

Please answer the above about the AC or DC input too.

Graahm

Reply to
Eeyore

The only way you're going to get from a +20V to +5V and +/-12V outputs with one component is with a DC-to-DC converter.

Look at this from Jameco:

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Their P/N 217648CM is a MeanWell (and I'm sure you do) DC-to-DC converter with triple output. This is a rather expensive one part solution to your problem.

If you want cheap, you'll have to consider going with more than one component. For a low current requirement, I'd think the lowest cost solution *is* a 7812 and 7805, with a small switcher to convert the

+20V to -12V.

If you want more help, you'll also have to mention your total power requirements for each power source (i.e. how much current do you need?)

Good luck Chris

Reply to
Chris

y u hv 2 us jst 1 chp chp? :( btw ur 4 7xxx chps wnt wrk - u nd n nvrtr 2 2 gt -V frm +V.

u cn lk @ Mxm. thy hv mltpl otpt dc-dc chps. Mxm cn smtms b 2 hrd 2 by frm if u r nt v v bg cmpny.

formatting link

Tim, getting down with the kids.

Reply to
Tim Auton

I could actually understand that. Perhaps I should list it as a language skill on my CV ;)

Cheers

PeteS

Reply to
PeteS

Wicked !

Graham

Reply to
Eeyore

Mad props, Tim. U got skillz. ;-)

Cheers Chris

Reply to
Chris
[snip!]

Simply pull the waitband of your trousers half-way down your arse-cheeks and typing that way will come naturally to you too. I think the nerves corresponding to the vowels must be located at the top of the gluteus maximums and sensitive to cold.

Tim

Reply to
Tim Auton

He wants dual-dual though !

Graham

Reply to
Eeyore

you need a DC-DC converter chip with +&- out.. look at mouser, Digikey etc... they have Dual output types

--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5
Reply to
Jamie

Reply to
aaryaluv

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