A 3.2 Gbit/s CML Transmitter With 20:1 Multiplexer In 0.18 CMOS Technology

In this paper, a 3.2Gb/s CML transmitter with 20:1 multiplexer was developed for integrating with 8/10B encoders in high speed network applications. Compared with the common 10:1 multiplexer, this 20:1 transmitter reduces the required operating frequency in routers or switches by half. A double phase source coupled logic based differential circuit is used to achieve the 20:1 serialization with reduced noise effects. A low-power PLL is embedded for generating on chip dual phase clocks. A wide-band low power high speed CML output buffer could provide 250mV output voltage swing up to 10Gb/s. The overall chip size is 650mumtimes950mum with power consumption of 104 mW at 3.2Gb/s