A 28 Gb/s 1.6 pJ/b PAM-4 Transmitter Using Fractionally Spaced 3-Tap FFE and Gm-Regulated Resistive-Feedback Driver

作者：Ju Haram; Choi Moon Chul; Jeong Gyu Seob; Bae Woorham; Jeong Deog Kyoon^*

来源：IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS, 2017, 64(12): 1377-1381.

DOI：10.1109/TCSII.2017.2748607

• PAM-4 transmitter
• resistive-feedback driver
• feed-forward equalization
• output impedance
• wireline

We presents an energy-efficient PAM-4 transmitter that provides a controlled output impedance, scalable output voltage swing, and fractionally spaced feed-forward equalization (FFE). By using a resistive-feedback output driver, the proposed PAM-4 transmitter can reduce the power dissipation in the pre-driver stages compared with conventional transmitters. It also offers a more straightforward implementation of a 3-tap FFE owing to the simple current-summing structure of the pre-driver. In addition, the output impedance of the proposed output driver is controlled by regulating the Gm of the driver cell, which results in good signal integrity for high-speed operation without the use of peaking inductors. A prototype chip is fabricated in 28-nm CMOS technology and occupies an active area of 0.048 mm(2). It achieves a data rate of 28 Gb/s, exhibiting the state-of-the-art energy efficiency of 1.59 pJ/b for the differential output swing of 207 mV.

• 出版日期2017-12