A 20 Gbps PAM4 Data Transmitter ASIC for Particle Physics Experiments

TL;DR

This paper introduces GBS20, a 65 nm CMOS ASIC capable of transmitting data at 20.48 Gbps using PAM4 modulation, designed for particle physics experiments, with efficient power consumption and integrated clocking and scrambling features.

Contribution

The paper presents a novel 20 Gbps PAM4 transmitter ASIC with integrated clocking, scrambling, and low power consumption, tailored for high-speed particle physics data acquisition.

Findings

Operates reliably at 20.48 Gbps with PAM4 modulation.

Power consumption is below 238 mW, reduced to 164 mW in low-power mode.

Successfully tested with VCSEL-based optical output.

Abstract

We present the design and test results of a novel data transmitter ASIC operating up to 20.48 Gbps with 4-level Pulse-Amplitude-Modulation (PAM4) for particle physics experiments. This ASIC, named GBS20, is fabricated in a 65 nm CMOS technology. Two serializers share a 5.12 GHz Phase Locked Loop (PLL) clock. The outputs from the serializers are combined into a PAM4 signal that directly drives a Vertical-Cavity-Surface-Emitting-Laser (VCSEL). The input data channels, each at 1.28 Gbps, are scrambled with an internal 27-1 Pseudo-Random Binary Sequence (PRBS), which also serves as a frame aligner. GBS20 is tested to work at 10.24 and 20.48 Gbps with a VCSEL-based Transmitter-Optical-Subassembly (TOSA). The power consumption of GBS20 is below 238 mW and reduced to 164 mW in the low-power mode.