Design of FDOA ASIC for Charge Measurement Circuit in Shaping and Peak Detection Method

The technical route of amplification & shaping and digital peak detection has been widely used in charge measurement in particle physics experiments. Since most high-precision Analog to Digital Converters are differential voltage inputs, it is necessary to convert the single ended signal after amplification & shaping into differential signal based on factors such as improving measurement accuracy and reducing common mode interference. In order to meet the requirements of high precision, low power consumption and multi-channel of readout electronics in particle physics experiments, a FDOA (Fully Differential Operational Amplifier) ASIC (Application Specific Integrated Circuit) is customized and designed. In order to achieve larger slew rate and load capacity with lower power consumption, the FDOA ASIC is designed by combining current multiplexing technology and class AB push-pull amplifier structure. Based on 180 nm CMOS process, the circuit design, simulation and streaming are completed. The test results show that the single channel power consumption of the chip is about 28.3 mW, and the slew rate is about 745.4 V/μs. The load capacity is about ±50 mA, the noise performance is about 173 μV. And the THD (Total Harmonic Distortion) is better than 70 dB under the signal input of 20 MHz and 2 Vpp.