A 1.28 pJ/b 32 Gb/s Digital Isolator Using Coupled-Line Transformer for High-Speed Data Links

This paper presents a high-speed, energy-efficient and compact digital isolator using a coupled-line transformer (CLT) for high-throughput galvanically isolated data links. The isolator employs a broadband CLT built in the package substrate as the isolation barrier, enabling an efficient pulse-polarity baseband data transmission scheme without carrier modulation. A transceiver incorporating a transmitter with edge rate control and a receiver with damping and equalization is designed to realize robust and efficient data transmission across the isolation barrier. Fabricated in a 28-nm CMOS technology, the prototype achieves error-free (BER<10^-12) isolated data transmission at a record data rate of 32 Gb/s with an energy efficiency of 1.28 pJ/b, while occupying a compact core area of 0.034 mm^2.