This paper reports an 8-bit current steering-type cryogenic digital-to-analog converter (DAC) module using HLMC 40nm low-power (40LP) technology for fast qubit initialization in quantum computers. Based on the generic design platform generated from our cryo-CMOS compact model, we optimize the circuit to ensure its correct function with temperature-insensitive non-linearity. Benefiting from the integration of the nA-range on-chip current reference and appropriate gate sizing, a low power consumption of 13.8 µW under the mixed power supply of 1.1 V/1.8 V is achieved in this DAC design with an active area of 0.0074 mm2. With the realization of the stable output range of 6 mV and fast sampling rate of 140 MS/s at low temperatures, our cryo-DAC is able to manipulate the physical qubit, hence laying a solid foundation for practical large-scale quantum computing applications.