A 0.3-to-5.5 GHz Digital Frequency Discriminator IC with Time to Digital Converter

A 0.3 to 5.5 GHz range, 50ns-detection Digital Frequency Discriminator (DFD) using a Time to Digital Converter is presented. Wide frequency range and high accuracy are achieved by an averaging technique using all periods of the input signal and periodical number during the measurement time using TDC. The DFD, fabricated in 0.18-μm SiGe-BiCMOS, achieves measured absolute error below 0.39MHz and standard deviation below 1.53MHz-RMS during 50 ns detection time in the band from 0.3 GHz to 5.5 GHz.