A 150 MHz 13b 12.5 mW IF digitizer

A sub-sampling IF digitizer that uses a passive sampling mixer to improve distortion and a BiCMOS comparator to improve the SNR of a passive loop-filter based /spl Sigma//spl Delta/ converter is described. Volterra series analysis allows accurate prediction of distortion in the sampling mixer. A bipolar emitter-coupled pair based preamplifier in the comparator helps to relax overdrive recovery requirements of the regenerative latch and improve the speed of the comparator.