A 0.25-um BiCMOS Feed Foward Equalizer Using Active Delay Line for Backplane Communication

In this paper, a BiCMOS equalizer using an active delay line structure for backplane communication is investigated. Equalization is achieved using a finite impulse response (FIR) filter. The filter is implemented using variable gain blocks and delay elements. The variable gain function is implemented using a Gilbert cell topology, modified for high-speed application. The delay line is implemented using active devices. The active delay line consumes less area than a passive L-C delay line, and has improved bandwidth as well as performance over process variation. The equalizer is implemented in a 0.25-mum BiCMOS technology. To the best our knowledge, it is the first BiCMOS equalizer using an active delay line approach.