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

In this Letter, a millimeter wave integrated transversal filter operating up to 84 Gb/s is presented. The implemented topology offers improved testability, which allows to characterize the filter in both time and frequency domain. The filter has an input and output return loss lower than -10 dB up to 67 GHz, and is used to shape the frequency response across a channel. Using this filter, equalization of a NRZ input to either a 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 a 130nm SiGe BiCMOS process, has a die area of 2.5mm x 1.4mm and consumes 210mW from a 2.5V power supply.