A controlled transconductance circuit (CTC) is disclosed. The CTC includes (i) a transistor comprising a drain terminal, a gate terminal, and a transistor source terminal, (ii) a biasing circuit element connected between the transistor source terminal and a CTC source terminal, and a variable capacitor connected between the transistor source terminal and a constant voltage terminal where the constant voltage terminal is adapted to receive a constant voltage, and (iii) a CTC control terminal adapted to control a transconductance of the CTC by controlling a capacitance of the variable capacitor.