Studies On High Speedand Wideband Linear Analog Signal Isolation Amplifier

The analog signal isolation amplifier has been used in the field of video,audio and communication . Through systematic design, circuit design, layout design and performance simulation and validation, this paper develops a high speed and wideband linear analog signal isolation amplifier, which is on the ground of electrical characteristics'guideline requests. The design has so many virtues, such as structure simple ness, high precision, high-speed, wideband, low lost and can be integrated.Compare the Current Feedback technology with the Voltage Feedback technology and compare the CB process with the CMOS process to get a feasibility way, and use the Current Feedback technology, which is based on the Complementary Bipolar Process, to achieve high-speed and wideband, linear optical coupling achieve isolation. Through carefully analyze and optimize the structure of circuit, now the circuits have been designed, pre-layout simulation and portion of layout design have been completed. The simulation results show that all the design specifications are met. The input resistance is 3.7M?, the output resistance is 2.5?, open-loop gain is 36dB, phase margin is 51°when the compensate capacitor is 3 pF , common-mode rejection ratio is 60～80 dB,–3dB bandwidth is maintained within the range of 15MHz~42MHz, and the slew rate can achieved 200V/μs , has a perfect linearity and temperature characteristic. In addition, lots of functions circuits are designed, such as thermal shutdown, over voltage protection, under voltage lockout, over current protection, and so on.