Apparatus and methods for actively terminated digital-to-analog conversion

A method of electrical termination, the method comprising:

• generating a first bias voltage and a second bias voltage using a bias circuit;
• biasing a gate of at least one PMOS termination transistor of a DAC using the first bias voltage;
• biasing a gate of at least one NMOS termination transistor of the DAC using the second bias voltage;
• and
• terminating an output of the DAC based on a small signal resistance of the at least one PMOS termination transistor and on a small signal resistance of the at least one NMOS termination transistor.

An apparatus comprising:

• a DAC including a data input configured to receive a digital input signal and an output configured to generate an output current, wherein the DAC comprises an active termination circuit including one or more PMOS termination transistors and one or more NMOS termination transistors;
• and
• a means for generating a first bias voltage and a second bias voltage, wherein the first bias voltage is configured to control a small signal resistance of the one or more PMOS termination transistors, wherein the second bias voltage is configured to control a small signal resistance of the one or more NMOS termination transistors, and
• wherein the one or more PMOS termination transistors and the one or more NMOS termination transistors provide active termination to the output of the first DAC.