Abstract: Differential buffers are used in a voltage-controlled oscillator to provide pairs of complementary phase signals. The preferred arrangement includes a ring of the differential buffers. Each differential buffer has a current control input, and the current control inputs of the buffers are all connected to a control voltage input to simultaneously adjust the propagation delay of each of the buffers. In contrast to a conventional ring oscillator, which has an odd number of stages, a ring oscillator made of differential buffers can have an even number of buffers to provide a number of phases that is a multiple of four. The differential buffer preferably includes a pair of CMOS inverters sharing a common PMOS current sourcing transistor and a common NMOS current sinking transistor.

Abstract: A CMOS current steering switch circuit includes a switch formed of a pair of transistors of one conductivity type having a source terminal connected to a node to which a constant current source is also connected. The drain terminals of the transistors comprise the switch circuit's output terminals. The transistor's gate terminals are controlled by a pair of buffers comprising transistors of the other conductivity type that receive differential input signals that control the switch circuit. The buffers limit the voltage swings of the control signals applied to the gate terminals so that the transistors comprising the switch are not both off at the same time.