Abstract: A two-bit serializer circuit as described herein includes programmable delay elements having adjustable phase delay that allows for phase tuning of two parallel input signals relative to an output multiplexer select signal. The two parallel input signals are retimed relative to a reference clock signal, and one of the retimed signals is processed by a fixed delay element. This delayed intermediate signal is further delayed using one programmable delay element; the other retimed signal is delayed using another programmable delay element. The delayed output signals generated by the programmable delay elements are utilized as input signals to a high speed output multiplexer. The multiplexer output select signal represents a buffered version of the reference clock signal. The programmable nature of the serializer circuit facilitates tuning to reduce jitter in the serialized output signal.

Abstract: A ring oscillator stage includes two differential transistor pairs configured to add an adjustable amount of delay to a differential input signal. Each differential pair is biased with a bias current transistor; the bias current transistor is “protected” by a voltage-clamping transistor that limits the drain voltage of the bias current transistor. The voltage-clamping transistors enable use of a power supply voltage (VDD) that would otherwise exceed the reliability breakdown voltage limit of the bias current transistors.

Abstract: An amplitude of a differential output signal at a differential multiplexer is maximized by presenting, in response to a differential selection signal, a high impedance to each output port of each differential transistor of a non-selected differential transistor pair. A differential input signal is received at each differential transistor pair. Each transistor of each differential transistor pair is connected to a current source through an independent selection transistor. In response to the differential selection signal, each of the selection transistors is placed in an off state resulting in a high impedance between the output ports of the transistors of the non-selected differential transistor pair.

Abstract: An impedance element connecting the outputs of two transistors of a wide-bandwidth amplifier forms a zero. The output of transistor is connected to a current source. The wide-bandwidth amplifier has a bandwidth greater than conventional amplifiers utilizing a single current source without an increase in power dissipation.