  We make use of a custom-designed cryo-CMOS multiplexer (MUX) to enable
multiple quantum devices to be characterized in a single cool-down of a
dilution refrigerator. Combined with a packaging approach that integrates
cryo-CMOS chips and a hot-swappable, parallel device test platform, we describe
how this setup takes a standard wiring configuration as input and expands the
capability for batch-characterization of quantum devices at milli-Kelvin
temperatures and high magnetic fields. The architecture of the cryo-CMOS
multiplexer is discussed and performance benchmarked using few-electron quantum
dots and Hall mobility-mapping measurements.
