We report on the implementation of a multiplexer that uses superconducting
quantum interference devices (SQUIDs) to read out low-impedance cryogenic d
etectors. Using prototype chips, a circuit was built which interfaces eight
input SQUID channels with a close-packed array of eight transition-edge se
nsor (TES) infrared bolometers. Circuit elements were measured and crosstal
k specifications are reported. Digital feedback is employed to flux-lock a
single element in the array of SQUIDs. Published by Elsevier Science B.V.