High-speed multi-channel CCD preamplifier circuit principle

Probe high frequency needle 10445 with line high frequency needle with 1 high frequency core can pass 3A

Factory direct 5050 yellow light LED 5050 yellow light 5050 yellow high quality high brightness

Overview:
In high-speed imaging applications, the number of output channels of the CCD is large, and the speed of each channel is also high. Multi-channel output requires multiple amplifiers to amplify the signal. When the number of amplifiers is large, it is difficult to place the amplifier close to the CCD when the board layout is made. The low-pass circuitry created by the longer board traces and the low-pass circuitry formed by the CCD output resistor severely limits bandwidth. Therefore, the high frequency compensation method is adopted in the circuit design to solve the problem of bandwidth limitation. In the circuit board design, the method of removing the ground plane of the feedback terminal of the operational amplifier is adopted to avoid the self-oscillation of the amplifying circuit.

0 Introduction Charge-coupled device (CCD) has the advantages of low noise, wide dynamic range, high speed, and linear response. In high speed imaging applications, the CCD must have the ability to have multiple channels of output. Increase the speed of the imaging system with multi-channel parallel output. The speed of each channel must also be maintained at a high speed, usually operating at 25 to 40 MHz per channel. The output resistance of the CCD is not very small. Under normal circumstances, its output resistance can reach about 300 Ω. Therefore, the preamplifier circuit is required to perform impedance transformation to make the output resistance small. And make the preamplifier circuit as close as possible to the CCD. Because if the preamplifier circuit and the CCD have a certain distance, the circuit board traces will have a certain parasitic capacitance. The parasitic capacitance and the CCD output resistance form a first-order low-pass circuit that limits the bandwidth of the circuit. However, CCD multi-channel output requires multiple amplifiers to amplify the signal. When the number of amplifiers is large, there is not enough space in the board layout to place the amplifier close to the CCD. The amplifier cannot be placed close to the CCD, and the parasitic capacitance of the trace limits the bandwidth. Therefore, bandwidth can only be extended by high frequency compensation technology. It should be noted that the high frequency compensation must not cause the amplifier to be unstable. In addition, high-speed operational amplifiers are also poorly designed and self-oscillating. Therefore, self-oscillation is avoided by removing the ground plane of the op amp feedback terminal in the board design.
(Please read the PDF for details)