PHASE-LOCKED LOOP AND DELAY-LOCKED LOOP INCLUDING DIFFERENTIAL DELAY CELLS HAVING DIFFERENTIAL CONTROL INPUTS

摘要

A differential delay cell is provided herein that not only receives a pair of differential input values, but also receives a pair of differential control values for delaying the differential input values to produce a pair of differential output values. As such, a delay cell is provided, which is truly differential, and therefore, capable of demonstrating a significant improvement in noise performance. The differential delay cell of the present invention also demonstrates high frequency stability around the center frequency, constant gain and increased tuning range capabilities. In this manner, the differential delay cell may be used in PLL or DLL designs as part of a low noise VCO or a low noise delay line, respectively.