10 Gb/s modulator driver IC with ultra high gain and compact size using composite lumped-distributed amplifier approach

Abstract

In this paper, a 10 Gb/s modulator driver MMIC is presented using a composite lumped-distributed amplifier approach, which allows a very compact chip size with ultra high gain and high output voltage swing. The chip size is further reduced using double-input distributed amplifier topology. The designed modulator driver is fabricated using a depletion-mode 0.15 /spl mu/m GaAs pHEMT process. The chip size is as small as 1.1 mm/spl times/1.9 mm. Measured small-signal gain is as high as 31.5 dB with 3 dB bandwidth of 15.0 GHz and good input/output return losses. The measured eye diagram shows clear eye open and output voltage swing of 7.4 V/sub pp/ at the input of 10 Gb/s 2/sup 23/-1 pseudorandom NRZ data. The input swing is 0.22 V/sub pp/. To the knowledge of the authors, this result is among the highest gain per chip area with high output voltage swing for 10 Gb/s modulator driver ICs.