A variable load circuit for adjusting a phase of a differential signal
including a first transistor having a first terminal adapted to receive a
first component of the differential signal, a second transistor having a
first terminal adapted to receive a second component of the differential
signal and a second terminal coupled to a second terminal of the first
transistor, and a variable current source coupled to a third terminal of
both the first and second transistors. The variable current source
generates a bias current based on a control signal. For each of the first
and second transistors, a first capacitance is created between the first
and second terminals, and a second capacitance is created between the
first and third terminals. The first and second capacitances are each a
function of the bias current and thus the control signal and operate to
adjust the phase of the differential signal.