Very Low Noise Multiplexing with SQUID and SiGe HBTs For Readout of Large Superconducting Bolometer Arrays

International audienceThis paper presents an ultra low noise instrumentation based on a standard BiCMOS SiGe 0.35 μm ASIC operating at cryogenic temperatures. The main functions of the electronic circuit are the readout and the multiplexing of SQUIDs/TES. We report the cryogenic operation of the ASIC dedicated to the readout of a 2×4 pixel demonstrator array. We particularly emphasize on the development and the test phases of an ultra low noise (0.2 nV/sqrt Hz) cryogenic amplifier designed with two multiplexed inputs. The cryogenic SiGe amplifier coupled to a SQUID in a FLL operating at 4.2 K is also presente