Transconductor circuit

A transconductor circuit, comprising:

• a first input node for receiving a first input signal and a second input node for receiving a second input signal;
• a first differential amplifier comprising a first transistor and a second transistor, wherein a control node of the first transistor is coupled to the first input node and a control node of the second transistor is coupled to the second input node, and respective controlled paths of the first and second transistors are coupled with each other to form the first differential amplifier, the first differential amplifier having a first offset voltage;
• and
• a second differential amplifier comprising a third transistor and a fourth transistor, wherein a control node of the third transistor is coupled to the first input node and a control node of the fourth transistor is coupled to the second input node, and respective controlled paths of the third and fourth transistors are coupled with each other to form the second differential amplifier, the second differential amplifier having a second offset voltage different from the first offset voltage;
• the controlled paths of the first and second transistors are coupled in parallel to the controlled paths of the third and fourth transistors, respectively;
• a first resistance circuit coupled between the first differential amplifier and at least one current source, and a second resistance circuit coupled between the second differential amplifier and the at least one current source;
• the first resistance circuit comprising a fifth transistor having a control node coupled to the controlled paths of the third and fourth transistors, and the second resistance circuit comprising a sixth transistor having a control node coupled to the controlled paths of the first and second transistors;
• the first resistance circuit further comprising a seventh transistor that is coupled to form at least one first diode and coupled between the first differential amplifier and the current source in a forward direction, and the fifth transistor having a controlled path coupled in parallel to the first diode, and the second resistance circuit further comprising an eighth transistor that is coupled to form at least one second diode and coupled between the second differential amplifier and the current source in a forward direction, and the sixth transistor having a controlled path coupled in parallel to the second diode.

A circuit, comprising:

• a first differential amplifier coupled to first and second input nodes and having an offset voltage;
• a second differential amplifier coupled to the first and second input nodes and having a second offset voltage different from the first offset voltage;
• and
• a first resistance circuit coupled between the first differential amplifier and at least one current source, and a second resistance circuit coupled between the second differential amplifier and the at least one current source, the first and second resistance circuits comprising a first transconductance element and a second transconductance element, and wherein the at least one current source is controllable to control the transconductance of the first and second transconductances without degrading linearity of the circuit.