Design Of Highly Reliable Radiation Hardened Interface Module Based On Low Power High Gain High Transient OTA

With the rapid development of national space undertakings, integrated circuit design work meets new challenges in modern aerospace applications. The RS-422 protocol interface circuit with its work stability and high reliability, has been widely used in the field of aerospace.The RS-422 protocol specification is usually applied in the general interface circuit with low-frequency and long-term transmission. This kind of general interface circuit consists of two parts, a transmitter and a receiver. The transmitter is driven by a simple digital logic and larger output tubes, and the receiver, at the end of the transition, finish the attenuated signal recognition after long term transition by differential amplifier. While the traditional receiver, often use simple secondary amplifier to realize the signal recognition. The traditional structure circuit has little gain, reflects the slow speed, but has large power consumption.In recent years, high speed and low power consumption design has become a focus in IC design field, and the whole market system are also been put forward. The requirement of high speed and low power consumption has pushed the traditional receiver urgently to improve optimization. IC designers start to reconsider how to improve the response speed and reduce power consumption. OTA has been widely used, due to its driven by current, and its adjustable gains. In this paper, OTA(Operational Transconductance Amplifier) amplifier is used to replace the traditional receivers. Through the analysis of traditional OTA circuit, and continuous design optimization, the paper finally realizes the receiver circuit of high speed, but low power consumption. For the OTA circuit in this paper, its circuit gain reaches is 60 db, unit gain bandwidth (GBW) is 2.213 MHz, phase margin is 60.11°, static-state current is 30μA, plus voltage slew rate is 44V/μs, minus voltage slew rate is 74.9V/us. With the final design of the interface module circuit to RS-422 protocol, static current is 3.4 mA, propagation delay Tplh is 20.02 ns, Tphl is 18.5 ns.In order to meet more applications, the designed interface module circuit in this paper has applied ESD(Electro Static Discharge) reinforcement design, and radiation hardened design. The flow structure of ESD test has also been made. The ability of ESD with the designed chip in the paper has reached HBM-4000V above.