Low power analogue equaliser with adaptive digital tuning for fast ethernet

Abstract

This work presents an analogue equaliser with digital tuning. It compensates the losses introduced by up to 120 m long category 5 unshielded twisted pair cables and baseline wander (BLW). The equaliser is designed for Fast Ethernet with a symbol rate of 125 MHz. A g m-C filter, based on three first-order high pass filters, is used to compensate the cable loss. To minimise power consumption, three operational transconductance amplifiers (OTAs) are merged into a novel multi-input OTA structure. Additionally, a robust digital control logic is presented to automatically adjust the parameters of the equaliser for different cable lengths. A fast settling time below 250 µs is demonstrated for different scenarios. The equaliser is fabricated as part of a Fast Ethernet PHY chip in a 180 nm CMOS technology of GLOBALFOUNDRIES. Measurement results demonstrate error-free data transmission (bit error rate below 10 −12) for cable lengths up to 120 m. The power consumption of the analogue equaliser ranges from 2.3 mW (short cable) to 6.5 mW (120 m cable). To the best of the authors' knowledge, this is the lowest power consumption of an analogue equaliser for Fast Ethernet, supporting additional BLW and flat loss compensation reported to date.

Categorization and Characterization of Time Domain CMOS Temperature Sensors

“…As the CMOS process scales down and the supply voltage shrinks, the recent trend is to prefer the time domain signals such as the frequency, period and delay time to the voltage and current signals [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. So, the time domain CMOS temperature sensors are holding more attraction than the traditional CMOS temperature sensors based on the voltage and/or current signals.…”