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Can i use dual supply op amp in single supply mode? Is it okay to convert a bipolar voltage to uni polar and then feed it to a single supply op amp(amplifier)?

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  • \$\begingroup\$ A so called dual supply device will work in single supply mode; just make sure that the difference between the V+ and V- supply pins is within the datasheet limits. \$\endgroup\$ – Peter Smith Apr 21 '16 at 7:31
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Can i use dual supply op amp in single supply mode?

From the perspective of an op-amp, it sees two power rails, one more positive than the other and that's all it cares about. If you happen to have +/-15V rails, you are doing so because it is important that your signal is referenced to an extended ground that connects to other "systems".

If you have an arbitrary ground and +/-15V rails then you might as well have 0V and +30V as your rails with the nominal signal reference point at +15V.

Bottom line - with probably higher than 99% probability, there isn't an op-amp that is specifically "dual rail" or "single rail". From my experience I cannot ever remember seeing one and I've had a lot of experience!

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  • \$\begingroup\$ How about Apex PA107? ;) \$\endgroup\$ – Oleksandr R. Apr 21 '16 at 12:30
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    \$\begingroup\$ @OleksandrR. That isn't an op-amp - it only has one input so that rules it out from being classified as an op-amp (despite them calling it one). en.wikipedia.org/wiki/Operational_amplifier \$\endgroup\$ – Andy aka Apr 21 '16 at 12:36
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You have asked two complementary questions.
Did you mean to?


Yes, but ... .

As long as you do not violate any of the specifications it will work.
In many cases that puts excessive constraints on your design.
Most dual supply opamps have an input voltage range that does not include either supply rail. And Vout often does not swing all the way to positive or negative supply.
Some opamps are sold as RIRO where
RI = Rail IN and
RO = Rail

RI means the input voltage can swing all the way to both rails during operation.

And RO means that the output can swing all the way to both rails during operation.

However even an RO opamp may not swing QUITE all the way to the rails. Sometimes the few mV matters.

A very few oamps have internal power supplies which supply voltages outside the rails so the input and output can swing TO the rails.

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  • \$\begingroup\$ Possible duplicate: electronics.stackexchange.com/questions/2962/… \$\endgroup\$ – Peter Smith Apr 21 '16 at 7:39
  • \$\begingroup\$ Some RR in devices can self-oscillate when they have a high impedance source, depending on implementation; this device linear.com/product/LT1638 can be unstable in high source impedance DC buffer applications. \$\endgroup\$ – Peter Smith Apr 21 '16 at 8:11
  • \$\begingroup\$ The actual nomenclature is RRIO for both sides and rail-to-rail if specified separately for both. A very common variant is "input common mode extends to GND/VSS", meaning input signal can go all the way to 0V (or negative rail) but not the supply voltage. Dual rail devices also work perfectly well with unbalanced voltages such as +24 and -5. Or you can supply single supply device with negative voltage if you need it to really go to GND but be vary of the max voltage. \$\endgroup\$ – Barleyman Apr 21 '16 at 8:38

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