A Highly Expandable Forwarded-Clock Receiver with Ultra-Slim Data Lane using Skew Calibration by Multi-Phase Edge Monitoring

Abstract

Abstract-A source-synchronous receiver based on a delay-locked loop is presented. It employs a shared global calibration control between channels, yet achieves channel expandability for high aggregate I/O bandwidth.The global calibration control accomplishes skew calibration, equalizer adaptation, and phase lock of all the channels in a calibration period, resulting in the reduced hardware overhead and area of each data lane. In addition, the weightadjusted dual-interpolating delay cell, which is used in the multiphase DLL, guarantees sufficient phase linearity without using dummy delay cells, while offering a high-frequency operation. The proposed receiver is designed in the 90-nm CMOS technology, and achieves error-free eye openings of more than 0.5 UI across 9-28 inch Nelco4000-6 microstrips at 4-7 Gb/s and more than 0.42 UI at data rates of up to 9 Gb/s. The data lane occupies only 0.152 mm 2 and consumes 69.8 mW, while the rest of the receiver occupies 0.297 mm 2 and consumes 56.0 mW at the 7-Gb/s data-rate and supply voltage of 1.35 V.