Operational transconductance amplifier with good linearity

An operational transconductance amplifier with a good linearity, comprising

• a first transistor coupled to a negative supply voltage input signal for receiving the negative voltage input signal and converting said negative voltage input signal to a first current signal;
• a second transistor coupled to a drain of said first transistor for maintaining drain voltage of said first transistor and transferring the first current signal from said first transistor to an output terminal;
• a third transistor coupled to a positive supply voltage input signal for receiving the positive voltage input signal and converting said positive voltage input signal to a second current signal;
• a fourth transistor coupled to a drain of said third transistor for maintaining constant drain voltage of said third transistor and transferring the second current signal passing through said third transistor to an output terminal;
• a reference voltage generation means for generating a reference voltage;
• a first operational amplifier having its negative input terminal coupled to a junction between said first transistor and said third transistor, its positive input terminal coupled to an output terminal of said reference voltage generation means, and its output terminal coupled to a gate terminal of said second transistor;
• a second operational amplifier having its negative input terminal coupled to a junction between said third transistor and said fourth transistor, its positive input terminal coupled to an output terminal of said reference voltage generation means, and its output terminal coupled to a gate terminal of said fourth transistor;
• and
• a current mirror for connecting said first and second operational amplifiers and said reference voltage generation means to said supply voltage source and a ground voltage source, said current mirror for obtaining total current.