[Background]: A multi-channel low temperature and low noise charge sensitive amplifier is designed for coaxial high purity germanium detector. The larger input capacitance of the detector introduces more noise

and to ensure high energy resolution

the front-end electronics need to meet strict noise performance standards. [Purpose]: The goal was to ensure high energy resolution by meeting stringent noise performance standards for front-end electronics. [Methods]: The low noise input transistor was obtained by using the optimized noise model

simulation iterations

and a special layout structure. The amplifier was designed to work at a 77K temperature

so that it could be placed as close as possible to the detector to further reduce parasitic capacitance and minimize noise. Larger transistor sizes could lead to gate leakage currents

which might alter the baseline of the amplifier output. To address this issue

we developed a low-noise charge-sensitive amplifier circuit with a feedback resistor module for leakage current compensation. This resistor feedback module mitigates sensitivity to power supply variations

temperature changes

and process deviations

and can compensate for leakage currents up to several micro amperes. Importantly

the circuit is self-biased

eliminating the need for external bias to adjust the feedback resistance value. [Results]: The test results show that the circuit operates stably over a wide temperature range of -196 ℃ to 55 ℃

and is able to drive the coaxial cable with a rapid and smooth transition. At a detector capacitance of 20 pF

2.5V pulses can be delivered to a 100 Ω load in less than 100 ns without ringing. At room temperature and -196 ℃

the quasi-Gaussian shaping time is 6 us

the noise performance of zero capacitance is 8.4 electrons

the FWHM of signal 4243.66 keV is 2.91 keV

and the energy resolution can reach 0.67‰. It has 5mV/fC output conversion gain and 0.15% linearity and low static power consumption of 7.92 milliwatts in a single channel. [Conclusions]:The performance achieved is sufficient for gamma-ray spectroscopy and pulse shape analysis using coaxial high-purity germanium detectors.