Transconductance amplifier and chip

A chip, comprising:

• a transconductance amplifier configured to generate an output current according to a positive input voltage and a negative input voltage, wherein the transconductance amplifier comprises:
• an input stage, configured to receive the positive input voltage and the negative input voltage and generate a positive output current and a negative output current, wherein the input stage comprises:
• a first transistor, wherein a gate thereof is coupled to the positive input voltage;
• a second transistor, wherein a gate thereof is coupled to the negative input voltage;
• a first resistor, serially connected between the first transistor and the second transistor;
• a third transistor, wherein a source of the third transistor is coupled between the first resistor and the first transistor, and a drain of the third transistor is configured to output the positive output current;
• and
• a fourth transistor, wherein a source of the fourth transistor is coupled between the first resistor and the second transistor, wherein a drain of the fourth transistor is configured to output the negative output current, wherein the first resistor has a first resistance, and a voltage difference between the positive input voltage and the negative input voltage does not affect a source to drain current of the first transistor and a source to drain current of the second transistor, so that a difference between the positive output current and the negative output current is fixed as 2*(the voltage difference between the positive input voltage and the negative input voltage)/the first resistance;
• and
• an output stage, configured to generate the output current according to the positive output current and the negative output current.