Im trying to create a +/- 2.5V supply from a +/-5V. I have a couple of 2.5V voltage references. Am I right in assuming that I need to get hold of a -2.5V reference? I did read an article that showed how I could use an inverter but I don't have any of those either.
There seems to be a gap in my knowledge because I don't really understand the difference between a voltage reference and a voltage regulator.
Thanks
If your 2.5 volt references are shunt type (two terminals that hold 2.5 volts when an externally limited current is passed through), you can use two of them to regulate a small (milliamperes) supply. If you want a more significant current from these supplies, you should use actual supply regulators. The adjustable LM317 and LM337 pair can be set to 2.5 volts output with a pair of resistors.
You need a low-impedance driver set at 2.5V relative to your current ground and this new low impedance driver needs to source or sink (two-quadrant, if my hobbyist knowledge of terms is close to right.)
You don't say what your _current_ requirements will be. There's a simple answer if you are talking about a few tens of mA. This is the TLE2426 "rail splitter." Also, an opamp set up with the 2.5V reference to its (+) input and its (-) tied to its output, which drives the new center point "ground" might be okay, assuming your opamp can deliver the current requirements you are looking for. (Or just use a resistor divider instead of the 2.5V reference, to the (-) input.) A discrete splitter could be formed out of transistors, too.
A reference usually has a very small _current_ drive capability -- not uncommonly in microamps -- to name one important difference.
Jon
Sorry, I meant (+), not (-).
Jon
use a 2425 and turn it around. the COM will be the - line and (IN) your common .
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