  Quantum computing (QC) requires cryogenic electronic circuits as control and
readout sub-systems of quantum chips to meet the qubit scale-up challenges.At
this temperature,MOSFETs transistors exhibition many changes such as higher
threshold voltage,higher mobility,and steeper substhreshold slope.We present a
cryogenic fully differential gain boosting-OTA used for a 14 bit Pipelined-SAR
ADC operating at 4.2K as the readout circuit for semiconductor-based quantum
computing system.Using $g_{m}/I_{d}$ methodology to get pre-computed lookup
tables based on the cryogenic 110nm BSIM4 model.The proposed OTA achieves very
high unity-gain<EMAIL_ADDRESS>and open-loop low frequency<EMAIL_ADDRESS>total power consumption is 2.66mW at 4.2K,and a setting accuracy better than
0.01\% with $f_{-3dB}$ of 37MHz in a closed-loop application.
