  We present the characterization and quality control test of a gigabit cable
receiver ASIC prototype, GBCR2, for the ATLAS Inner Tracker pixel detector
upgrade. GBCR2 equalizes and retimes the uplink electrical signals from RD53B
through a 6 m Twinax AWG34 cable to lpGBT. GBCR2 also pre-emphasizes downlink
command signals through the same electrical connection from lpGBT to RD53B.
GBCR2 has seven uplink channels each at 1.28 Gbps and two downlink channels
each at 160 Mbps. The prototype is fabricated in a 65 nm CMOS process. The
characterization of GBCR2 has been demonstrated that the total jitter of the
output signal is 129.1 ps (peak-peak) in the non-retiming mode or 79.3 ps
(peak-peak) in the retiming mode for the uplink channel and meets the
requirements of lpGBT. The total power consumption of all uplink channels is
87.0 mW in the non-retiming mode and 101.4 mW in the retiming mode, below the
specification of 174 mW. The two downlink channels consume less than 53 mW. A
quality control test procedure is proposed and 169 prototype chips are tested.
The yield is about 97.0%.
