Design Of 4-Bit 2Gs/s Ultra-fast Flash Converter And Combinatorial Application

Ultra-fast A/D converter is the most important part of the Signal Processing System, widely used in radar, high-speed broadband digital receivers, high-speed hard-dish, sonar and many consume electronics. At the same time, with the development of digital signal processing circuit, the speed of the A/D converter is becoming faster and faster. In the high-speed applications, full flash architecture has been considered the most appropriate architecture. But it is difficult to use traditional full flash architecture for a high-speed 8 bits and even more resolution application. Usually, in order to achieve high-speed and high resolution application, there are some new types of architecture of circuits needed. The full flash A/D converter with lower resolution is used as unit circuit.This paper introduces the design of a 4 bits 2Gs/s full flash A/D converter in detail, including the function and character. Because the design of ultra-fast A/D converter has a very high requirement for the analog blocks, such as offset and bandwidth, this paper has been made a detailed analysis and optimization for the main analog blocks, and then finishes the ultra-fast comparator which has the low offset voltage and power. Then, this paper makes some study of ultra-fast A/D converter that have 8 bits and 12 bits resolution, which using the designed 4 bits ADC as the unit circuit.This paper uses SMIC 0.18μm CMOS mixed-signal process. When the clock frequency is 2GHz, the design and simulation of every circuit modules is finished, then making function verification for the 4 bits 2Gs/s full flash A/D converter. The Power Voltage is 1.8V. When the clock frequency is 2GHz and the frequency of input signal is 400MHz, the power is 10.85mW.