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Virtual Ground.

I have here, a component from TI, The number on it as marked "2425C", all info found leads to being a Virtual Ground device with IN, COMMON, out.. the example spec's are 5V in, 2.5 out. now i understand the use of virtual grounds in systems that do not have a real - rail and is not using a DC-DC to derive it. what i would like to know is, a simple use/configeration for this device so that i can better understand it's operations. Virtual grounds that i have worked with before in the past used zener diodes that feed the - side of the bridge through these ZENERS that would connect to the main common. this way, components that needed some - voltage (in effect of), would simply connect it's

- rail to some point in this Zener diode chain to obtain the desired zener voltage. this of course, reduces the amount of V you get on the

  • rail. in using one of these TI2425C/ TLE2425CN etc...i would like to know how a simply wiring to obtain some - rail voltage. the PDF doc TI supplies does not show a test circuit, and it only mentions 5 VOLTS in and 2.5 out. i can only assume that, the INPUT maybe from the - side of the supply, common to the main common and output would be the - rail voltage of lets say 2.5 volts ?
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Reply to
Jamie
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The common terminal goes to a ground or a negative supply, the input terminal goes to a positive voltage supply, so that the total voltage from input to common is less than the 2425s rating input voltage rating. Then you get +2.5V on the output terminal w.r.t. the common terminal. It's just a precision 3-terminal regulator. The 2.5 V unit would usually be used in a system with a single 5 V supply, to get a virtual ground for analog circuits at V+ / 2.

-- John

Reply to
John O'Flaherty

This may help:

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Richard

Reply to
Richard Seriani, Sr.

Your post is a bit rambling, but I havent read the TI doc, but the main difference is that the VG will split the supply by two, so if the supply drifts a bit, eg a car battery, it will always be 1/2 the supply. With a zenered VG it will remain at the Vz, so as the supply varies, the psuedo + - supplies will not be symetrical

hope this helps

martin

Reply to
martin griffith

The TLE2425 is basically a 2.5 volt voltage regulator - the input is

+5 volts, and the output is +2.5 volts. It does not generate a negative voltage.

The idea of the thing is that you can operate your analog circuit on a single +5V supply (just +5 and ground), and the TLC2425 will produce a stable +2.5 volts that will connect to the points in your circuit that would go to ground if you were using a bipolar supply (like +5 and

-5).

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Peter Bennett, VE7CEI  
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Reply to
Peter Bennett

It is IMHO a pretty useless part with an awful lot of noise. You can configure almost any opamp to sink and source 20mA and a voltage reference to do the same. Only certain ADCs with a single reference and low speed can make advantage of this IC, for opamps it is better to just use a voltage divider for the reference voltage. If you had read the datasheet, you would know that it is powered fro either the +5V rail or higher.

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ciao Ban
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Reply to
Ban

thanks, that cleared it up, i also found a sight that was helpfull.

formatting link

i understand the practice of doing so,i just have never seen that done in a single package with no components like that.

--
"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5
Reply to
Jamie

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