The Design Of An Eight Channel High Speed Video Amplifier

With the development of 5G networks and artificial intelligence,the speed of signal processing is getting faster and faster,and the complexity of the system is getting higher and higher,which puts forward higher requirements on the performance of the op amp:high performance,high integration,low power Consume.As the core component of mixed signal processing,operational amplifiers have a decisive effect on the performance of the entire system.At the same time,the flow of mixed signals is becoming more and more complex.The use of multiplexers to achieve channel multiplexing has also been widely used,for example in some security and video intersection systems.Make full use of the capacity of the channel,so that the data information of multiple channels can share a channel,greatly reducing the system cost and expanding the scope of application.Combining the two can achieve better performance.Therefore,the research and design of high speed op amps and multiplexers are of great significance.This article mainly designs an eight channel high speed video amplifier,which is mainly used for video intersection system.Firstly,the feedback method of high speed op amp is introduced.Then,the method of reducing noise and offset is discussed in terms of circuit structure and process,so as to make a choice for the input stage structure.The intermediate stage uses a current mirror load to achieve a larger bandwidth.In order to isolate the load,improve the driving capacity,and realize a wide swing output,the output stage uses a push-pull output structure.This article uses a wide swing cascode current source to obtain a stable bias current.In terms of stability,the traditional nested Miller compensation method is used.Then introduces the use of multiplexers to channel multiplex the input signal.In video systems,high off isolation can reduce image ghosting.The isolation of traditional CMOS analog switches is severely attenuated with increasing frequency.Therefore,in order to overcome this shortcoming,this paper designed a T-type switch to meet the design requirements,and finally analyzed the key indicators of the multiplexer.Simulation verification meets the design requirements.The process used in this paper is CSMC 0.5?m 5V/18V CMOS double polycrystalline double aluminum process.The simulation is carried out by using the Specture software,the layout is drawn and verified by Cadence,and the final flow sheet test is carried out.The simulation results show that the GBW is 50MHz,the SR is 200V/us,the off isolation level is-70d B,the leakage current is 2.76×10^-4p A,and the layout area is 1700um×1700um.