18.8 A 72Gb/s 2-1 PRBS Generator in SiGe BiCMOS Technology

The demand for higher data rates in communication networks raises the need for test equipment operating above 40Gb/s. PRBS generators are commonly used to provide test patterns for highspeed blocks such as MUX or CDR circuits. While generators with pattern lengths of 2-1 have been reported at rates of 100 Gb/s [1], a 2-1 pattern is required for testing CDRs to ensure that phase lock is maintained for data streams containing many consecutive ones or zeros. However, the high level of single-chip integration required for such long patterns above 40Gb/s remains an obstacle. Careful attention must be paid to system-level design and layout to ensure synchronous clocking of the 31 flipflops in the feedback shift register (FSR), even if the FSR is clocked with a half-rate clock or less. In this paper, a 2-1 PRBS generator in a 0.13μm SiGe BiCMOS technology with 150GHz-fT HBTs [2] is reported. The circuit is capable of producing output data rates of up to 72Gb/s, with manageable power dissipation, by using a high-speed low-voltage BiCMOS ECL/CML logic family.