1V supply CMOS DEMUX for 40-GB/S optical communication systems

A 1 V supply 1:2 demultiplexer (DEMUX) based on 0.13 mum CMOS technology is presented. It is designed for 40-Gb/s optical communication systems. This DEMUX achieved by a pair of master-slave flip-flops (MS-FFs) with opposite clock can operate at 40-Gb/s and beyond. Fully differential current mode logic (CML) is adopted to improve the bit rate of non-return-to-zero (NRZ) data stream and to suppress common mode disturbances. Output buffers for two outputs are employed to drive the external 50 Omega loads. On-chip shunt peaking (SP) inductors are used to boost the bandwidth. Stacked current source combined with low V
_T
(LVT) and regular V
_T
(RVT) NMOS is used so that the proposed DEMUX has good immunity against possible process, voltage and temperature (PVT) variations. This DEMUX IC dissipates a total current of 25 mA under a 1 V supply and consumes a chip area of 0.54 mm
²
with bonding pads.