A low switching time BiCMOS CML transmitter for high speed adaptive pre-emphasis serial links

Due to the advances in multimedia applications in recent years, the requirement for high user end bandwidth has increased significantly. The increase in data rates cause jitter requirements to become even more stringent. An adaptive finite impulse response (FIR) filter is proposed to compensate for the non-ideal channel causing data dependant jitter (DDJ), hence improving signal integrity. This paper proposes a current mode logic (CML) based transmitter which incorporates BiCMOS logic, to reduce the rise/fall times of the high speed transmitter. Simulation results of the BiCMOS CML transmitter is presented showing a 30 % improvement in rise/fall times under high current and high output load conditions.