Analysis of Driving Circuit and Design of PCB for Electron Multiplication of EMCCD

The driving circuit for an electron-multiplying CCD (EMCCD) is key to achieve its on-chip gain. This paper introduces a structure of the driving circuit recommended by the TI for its TX285SPD, analyzes the operating principle of the circuit, and simulates the driving circuit by the PSpice. The circuit is recommended to use a clock with a frequency of 35MHz and a voltage ranging from -4V to 22V. Our EMCCD camera requires a clock with a frequency of 30MHz and a voltage ranging from -4V to 22V. Although results from simulations of the driving circuit show it can meet our requirements, in practice the large frequency and voltage differences cause difficulties for our PCB (Printed Circuit Board) design for the driving circuit. Three different PCB schemes have been designed and the corresponding PCBs have been made. All these PCBs are tested and the input and output waveforms of the clocks are measured. The PCB of the first scheme uses a clock with a frequency of 30MHz and a voltage ranging from -4V to 13V, the PCB in the second design uses a clock of 40MHz and a voltage of -4V to 23V, and the clock in the third design also uses 40MHz and a voltage of -4V to 23V. But the third design is better than the second design in the quality of waveforms. We discuss some possible problems in the designs, and point out the correct design for the driving circuit. The advantages of integrated power design and integrated signal-processing design are obvious. We finally summarize some design skills and recommendations for the preferred design of driving circuits.