We present a demonstration of readout of physical cryogenic calorimetric signals from 20 mK with a two-stage amplifier using 180 nm CMOS technology placed at 20 mK and 700 mK. We observe a number of cryogenic effects in 180 nm CMOS that deviate from typical warm behavior, which are not prohibitive to their cryogenic operation but whose potential impacts we discuss. This represents a new step towards the viability of cryogenic electronics using 180 nm CMOS in cryogenic calorimetric experiments
