Hi,
single supply..dual supply.
An OPAMP has two supply pins. And it has no GND (supply) pin.
So talking about the supply ... the OPAMP doesn´t know what GND potential is.
So it doesn´t care if you use two 6V supplies or one 12V supply.
BUT
since an OPAMP has no GND pin connection one needs a voltage or a signal to reference to.
But this is a rather "therotical" reference.
See the picture below.
I´ve done a LTspice simulation.
Three time the same circuit:
* OP07 (any other OPAMP that can handle 12V total supply voltage will do) .
* same input circuit 100n in series with 10k to IN-
* same feedback circuit: 30k
* same circuit for IN+: 10k from positvie supply and 10k to negative supply.
* same output circuit 100n and 10k to GND
But all three have different power supplies.
* The first: single supply GND and +12V
* the middle: dual supply, +6V and -6V
* the right: single supply -12V and GND
But the output of all the circuits measured at the resistors is the exactely same.
And all OPAMPs do exactely the same.
Seen from each OPAMP´s view (onle the 5 nodes) there is no difference.
The difference is the point of the GND connection ... and thus the point to which the user referes the voltage measurement.
--> conclusion: Any standard OPAMP is able to operate on dual supplies as well as single suppliy.
***
A small test:
go to the left circuit and measure the voltage between -Supply and OUT: you will see the signal has an offset of +6V and swings with an amplitude of 3V
now go to the middle circuit and measure the voltage between -Supply and OUT: you will see the signal has an offset of +6V and swings with an amplitude of 3V
now go to the right circuit and measure the voltage between -Supply and OUT: you will see the signal has an offset of +6V and swings with an amplitude of 3V
--> from the OPAMP´s view its every time the same.
***
I hope this post doesn´t lead to more confusion than the single_supply / dual_supply specifications in the datasheets....
Klaus