A Wide-Band, 5-Tap Transversal Filter With Improved Testability for Equalization up to 84 Gb/s

A millimeter wave integrated transversal filter operating at up to 84 Gb/s is presented. The implemented topology offers improved testability, which allows for filter characterization in both the time and frequency domain. The filter has an input and output return loss better than 10 dB up to 67 GHz. Using this filter, frequency equalization of an NRZ input to either an NRZ or a duobinary output is demonstrated at 84 Gb/s across a channel consisting of a 5 cm differential grounded coplanar waveguide trace and a pair of 80 cm coaxial cables. The filter is implemented in 130 nm SiGe BiCMOS process, has a die area of 2.5 mm × 1.4 mm and consumes 210 mW from a 2.5 V power supply.