A driver, comprising: a circuit having complementary drive elements (T1, T2) with a common tail node (Tail), the drive elements to, in a differential mode, transmit one input signal (R, Rb) over a pair of complementary signal lines; at least one drive control circuit for the complementary drive elements (T1, T2) to, in a single ended mode, decouple the complementary drive elements (T1, T2) to enable separate drive of independent input signals (Ca1, Ca2) over respective ones of the complementary signal lines; at least one path coupling the tail node (Tail) of the complementary drive elements (T1, T2) to a reference node in the single ended mode; and an impedance control circuit to change an impedance provided by the at least one path at times when the independent input signals (Ca1, Ca2) are simultaneously driven to a common value, wherein the impedance control circuit is adapted to change the impedance provided by the at least one path responsive to the independent input signals (Ca1, Ca2), wherein the drive elements (T1, T2) include first and second transistors (T1, T2) interconnected at the tail node (Tail) in the differential mode and in the single-ended mode, and wherein the path extends from the tail node (Tail) to the reference node; wherein the first transistor comprises a first control terminal to receive a first input signal, a first current-handling terminal, and a second current-handling terminal; the second transistor comprises a second control terminal to receive a second input signal, a third current-handling terminal, and a fourth current-handling terminal coupled to the second current-handling terminal of the first transistor at the tail node (Tail); and wherein the impedance control circuit comprises a current source coupled between the tail node (Tail) and a supply terminal, the current source having a first and second control terminals to receive the first and second input signals (Ca1, Ca2) corresponding to the independent input signals, wherein the first and third current-handling terminals are coupled to respective ones of the complementary signal lines; wherein the drive control circuit is coupled to the second current-handling terminal of the first transistor at the tail node (Tail). a circuit having complementary drive elements (T1, T2) with a common tail node (Tail), the drive elements to, in a differential mode, transmit one input signal (R, Rb) over a pair of complementary signal lines; at least one drive control circuit for the complementary drive elements (T1, T2) to, in a single ended mode, decouple the complementary drive elements (T1, T2) to enable separate drive of independent input signals (Ca1, Ca2) over respective ones of the complementary signal lines; at least one path coupling the tail node (Tail) of the complementary drive elements (T1, T2) to a reference node in the single ended mode; and an impedance control circuit to change an impedance provided by the at least one path at times when the independent input signals (Ca1, Ca2) are simultaneously driven to a common value, wherein the impedance control circuit is adapted to change the impedance provided by the at least one path responsive to the independent input signals (Ca1, Ca2), wherein the drive elements (T1, T2) include first and second transistors (T1, T2) interconnected at the tail node (Tail) in the differential mode and in the single-ended mode, and wherein the path extends from the tail node (Tail) to the reference node; wherein the first transistor comprises a first control terminal to receive a first input signal, a first current-handling terminal, and a second current-handling terminal; the second transistor comprises a second control terminal to receive a second input signal, a third current-handling terminal, and a fourth current-handling terminal coupled to the second current-handling terminal of the first transistor at the tail node (Tail); and wherein the impedance control circuit comprises a current source coupled between the tail node (Tail) and a supply terminal, the current source having a first and second control terminals to receive the first and second input signals (Ca1, Ca2) corresponding to the independent input signals, wherein the first and third current-handling terminals are coupled to respective ones of the complementary signal lines; wherein the drive control circuit is coupled to the second current-handling terminal of the first transistor at the tail node (Tail).