We report on the design and performance of our second-generation 32-channel time-division multiplexer developed for the read-out of large-format arrays of superconducting transition-edge sensors. We present design issues and measurement results on its gain, bandwidth, noise, and cross talk. In particular, we discuss noise performance at low frequency, important for long interrupted sub-millimeter/far-infrared observations, and present a scheme for mitigation of low-frequency noise. Also, results are presented on the decoupling of the input circuit from the first-stage feedback signal by means of a balanced superconducting quantum interference device pair. Finally, the first results of multiplexing several input channels in a switched, digital flux-lock loop are shown.
Citation: Review of Scientific Instruments
Pub Type: Journals
bolometers, cryogenic electronics, microcalorimeters, multiplexer, SQUID, transition-edge sensors