A circuit for a transmitter driver is disclosed. The transmitter driver circuit includes a main voltage-mode driver circuit configured to receive an input signal at the input port and to drive an output signal at the output port. The transmitter driver circuit also includes a secondary circuit connected to the input port and the output port in parallel with the main voltage-mode driver circuit. The secondary circuit includes: a secondary voltage-mode driver circuit; a current source connected to the secondary voltage-mode driver circuit and controllable to enable or disable a current boost to the output signal; and a switch connected to the secondary voltage-mode driver circuit and controllable to enable or disable the secondary voltage-mode driver circuit to drive the output signal in parallel with the main voltage-driver circuit.