ColdADC: A 16-Channel Digitizer ASIC with 186 µV-rms noise and 10.5-bit ENOB at 77 K for the Deep Underground Neutrino Experiment

A 16-channel, 12-bit, 2 MS/s Digitizer ASIC, called ColdADC, intended as the digitizer for the DUNE Single-Phase Far Detector, is presented. ColdADC has an input buffer per channel and two 16 MS/s Pipelined ADCs that each digitizes the output of 8 preamplifiers. The ASIC was developed using specialized design techniques for long-term reliability in cryogenic environments and a customized cryogenic standard cell library. ColdADC, with a die area of approximately 52.4 mm2 and fabricated in 65 nm CMOS technology, achieves 186 µV-rms noise performance and 10.5-bit ENOB at a temperature of 77 K, while dissipating 425 mW (26.6 mW per channel). The prototype has been successfully interoperated with the intended preamplifier at cryogenic temperatures.