Finite impulse response analog receive filter with amplifier-based delay chain

Abstract

High-data rate channel interface modules and equalization methods employing a finite impulse response (FIR) analog receive filter. Embodiments include an illustrative channel interface module having multiple amplifier-based delay units arranged in a sequential chain to convert an analog input signal into a set of increasingly-delayed analog signals that are weighted and combined together with the analog input signal to form an equalized signal; and a symbol decision element operating on the equalized signal to obtain a sequence of symbol decisions. An interface that extracts received data from the sequence of symbol decisions. The delay units may employ one or more delay cells each having a common-source amplifier stage followed by a source follower output stage, the two stages providing approximately equal portions of the propagation delay. An enhanced gate-to-drain capacitance in the common-source amplifier may increase propagation delay while reducing bandwidth limitations.