A compact and power-efficient serial I/O targeting dense silicon carrier interconnects is reported. Based on expected channel characteristics, the proposed I/O features low-impedance transmitter termination, high-impedance receiver termination, and a receiver with modified DFE with IIR filter feedback (DFE-IIR). The DFE-IIR receiver uses a single additional IIR filter feedback tap to compensate many postcursors without paying the power and area penalty that would be incurred with a conventional high tap-count DFE. Equalization capabilities of the compact I/O at 10 Gb/s are demonstrated over various channels including conventional chip-to-chip and backplane links with half-baud losses of up to 27 dB. Finally, a transmitter-receiver pair operating over a 40-mm on-chip emulated silicon carrier channel was demonstrated to 8.9 Gb/s, at a link power efficiency of 1.9 mW/Gb/s. Index Terms-Backplane channel communication, chip-to-chip communication, compact I/O, continuous-time IIR filter, decision feedback equalizer, serial link, silicon carrier links.

Abstract-This work describes the architecture and circuit implementation of a high-data-rate, energy-efficient equalized transceiver for high-loss dispersive channels, such as RC-limited on-chip interconnects or silicon-carrier packaging modules. The charge-injection transmitter directly conducts pre-emphasis current from the supply into the channel, eliminating the power overhead of analog current subtraction in conventional transmit pre-emphasis, while significantly relaxing the driver coefficient accuracy requirements. The transmitter utilizes a power efficient non-linear driver by compensating non-linearity with pre-distorted equalization coefficients. A trans-impedance amplifier at the receiver achieves low static power consumption, large signal amplitude, and high bandwidth by mitigating limitations of purely-resistive termination. A test chip is fabricated in 90-nm bulk CMOS technology and tested over a 10-mm, 2-m pitched on-chip differential wire. The transceiver consumes 0.37-0.63 pJ/b with 4-6 Gb/s/ch.

No abstract

No abstract