Near-zero dead zone phase frequency detector with wide input frequency difference

An all-digital phase frequency detector design capable of accepting an infinite range of input frequency differences and [0 2π] radians input phase difference is presented. The proposed phase frequency detector design minimises the dead zone, supresses unwanted output glitches, achieves a high maximum operating frequency, can drive high-capacitive loads and avoids differential outputs. The proposed phase frequency detector takes advantage of a fast reset operation from modified tristate inverters acting as a D flip-flop. Simulation results indicate that the design can detect input phase differences as small as 750 fs apart for all process corners at input operating frequencies of 38 kHz-2.5 GHz in 1.2 V, 90 nm CMOS technology.