I am using LT6221 op-amp. Can I please know will I be able to generate a negative output in an op-amp with out powering the op-amp with negative power supply. i.e +V is connected to 3.3V and -V is connected to ground.
As per the theory we cannot get output voltage outside the range of Vcc - Vee. I don't know about the practical case.
And any way if this could be done then what was the need of amplifiers/clampers etc..
The supply to any passive circuit will define the range of output.
The only circuit that can be used to get an output beyond VCC-VEE range of the supplied circuit is a circuit called "charge pump" . It is basically a switched capacitor circuit that can be used to generate a voltage greater than the available power supply. It is a quiet complicated circuit and you have to be very careful not to cause any damage to any of the components you use due to over-voltage conditions. I don't recommend you use it unless you really need it.