A 3.125Gbps timing and data recovery front-end with adaptive equalization

A 3.125Gbps timing and data recovery front-end is described. Adaptive discrete-time analog forward equalizers implemented in the receiver are used to cancel intersymbol interference. The coefficients in the analog equalizers are continuously adjusted by a digital adaptation loop. To save power, the digital adaptation loop operates at a 32× subsample rate. The timing recovery is 2× oversampled and uses these equalizers in its path for robust performance in the presence of intersymbol interference. A quad 3.125Gbps transceiver core has been fabricated in a standard 0.18 μm CMOS process.