Multiphase Clock Architecture Research Articles

A 32 GSps multiplexer with 1 kbit memory for arbitrary signal generation for testing digital‐to‐analogue converters

Recent high-speed digital-to-analogue converters (DACs) cannot be easily characterised at their highest rate because of the very high cost of commercially available bit-error rate testers at the required DACs rate. Among possible solutions, an inexpensive approach is the use of a multiplexer (MUX) with built-in memory to provide the required bit stream for one input bit of the DAC. This work presents a half-rate 32 GSps MUX with 1 kbit built-in memory as a part of an arbitrary test signal generator for a DAC. The proposed system can be used to test DACs developed for future OFDM optical communications. Here, a bipolar-CMOS (BiCMOS) 0.25 μm SiGe process is utilised. One challenge is to optimise the power dissipation of such an MUX which requires employing several techniques. At the system level, the conventional tree structure was avoided because of the high number of latches required to re-time the clock and data signals. At the highest rates, a multiphase-clock architecture was utilised which halves the number of latches compared with a tree structure. The phase margin of the multiphase-clock structure is enhanced in this work. At lower rates, a one-stage MUX architecture was used which also halves the number of latches. Additionally, the latency between the analogue–digital interface is discussed. All the implemented circuits including the biasing of the whole chip and its routing are presented. The design and optimisation of the clock driver for low-power functionality is discussed. Measurement results show proper operation at 32 GSps. The total power dissipation is 875 mW, which is the lowest power among the designs usable for DAC testing and at the same rate class.

A 50-Gbit/s 450-mW Full-Rate 4:1 Multiplexer With Multiphase Clock Architecture in 0.13-$\mu{\hbox {m}}$ InP HEMT Technology

A full-rate multiplexer (MUX) with a multiphase clock architecture for over 40 Gbit/s optical communication systems is presented. The 4:1 MUX is comprised of a re-timer based on a D-type flip-flop (DFF) and a clock tree system that uses EXOR-type delay buffers to match its skews well to those of the data. The supply voltage is reduced to -1.5 V by analyzing the voltage allocation. Fabricated in a 0.13-mum InP HEMT technology, a DFF test circuit achieved 75-Gbit/s operation and exhibited performance sufficient to re-time 50-Gbit/s serialized data. The 4:1 MUX measurement results demonstrate successful 50-Gbit/s operation at room temperature, and 40-Gbit/s operation, which has 10-11 error free for 231 - 1 pseudorandom bit stream (PRBS) data, up to an ambient temperature of 90 degrees or down to - 1.24 V of supply voltage. The circuit consumes 450 mW at a - 1.5-V supply and exhibits an output jitter of 283 fs rms at 50-Gbit/s operation. We also propose a multiphase clock generator for a MUX that has a serialization of more than four channels.

A 165-Gb/s 4:1 Multiplexer in InP DHBT Technology

This paper presents a 4:1 multiplexer fabricated in InP double heterojunction bipolar transistor (DHBT) technology. The multiplexer works up to 165 Gb/s at a supply voltage of -3.2 V consuming 1.6 W. It is a half-rate multiplexer using a multi-phase clock architecture. The main design challenge was to ensure correct timing between clock and data signals

50-Gbit/s InP HEMT 4 : 1 multiplexer/1 : 4 demultiplexer chip set with a multiphase clock architecture

A 50-Gbit/s InP high electron-mobility transistor (HEMT) chip set of 4 : 1 multiplexer (MUX) and 1 : 4 demultiplexer (DMUX) integrated circuits (ICs) with a multiphase clock (MPC) architecture is described. The MPC architecture employs a quarter-rate four-phase clock generated by a toggle flip-flop inside the ICs, which reduces the number of circuit elements and lowers the power consumption. The fabricated 4 : 1 MUX and 1 : 4 DMUX ICs exhibited 50-Gbit/s error-free operations for 2/sup 31/-1 pseudorandom bit sequences with 1.71- and 1.42-W power consumption, respectively. Compared to conventional tree-type 4 : 1 MUX and 1 : 4 DMUX ICs using InP HEMTs, the MPC 4 : 1 MUX and 1 : 4 DMUX ICs operate at the same operating speed with less than one-third power consumption.

Low-power 50 Gbit∕s InP HBT 1:4 demultiplexer IC with multiphase clock architecture

An InP HBT 1:4 demultiplexer IC with a multiphase clock architecture is described that reduces the number of circuit elements and power consumption while maintaining operating speed. The IC operated at 50 Gbit/s with 1.17 W power consumption at a supply voltage of −4.5 V. Compared to an IC with a conventional tree-type architecture using the same InP HBTs, the power consumption is less than half while the operating speed of 50 Gbit/s is maintained.