Tunable transconductor

A circuit, comprising:

• a voltage divider configured to receive an input voltage (VIN) and provide a divided input voltage (VINDIV);
• a programmable impedance circuit coupled to the voltage divider and configured to:
• receive VINDIV;
• receive a digital tuning code;
• and
• modify an impedance of the programmable impedance circuit, as presented to an outside component, based on a value of the digital tuning code;
• a current mirror coupled to the programmable impedance circuit an output current (IOUT) terminal;
• and an amplifier coupled in a negative feedback topology to the programmable impedance circuit and the current mirror, the amplifier configured to drive the current mirror to cause the current mirror to provide IOUT at the IOUT terminal having an amount of current based on VIN and linearly proportional to the digital tuning code.

A method, comprising:

• receiving an input voltage and a tuning code;
• dividing the input voltage by a voltage divider to provide a divided input voltage;
• providing the divided input voltage to an input of a programmable impedance circuit, the programmable impedance circuit configured to present a constant impedance to the voltage divider irrespective of a value of the tuning code and to present a variable impedance at an output of the programmable impedance circuit based on the value of the tuning code;
• and
• providing an output current based on a value of the divided input voltage and on a value of the variable impedance.