Design Of RHBD Optical Receiver Chip Based On CMOS Process

Fieldbus Technology connects all devices in the industrial field by serial communication bus. This makes the singal bus and ground line constructing a ground loop, which can collect noise in the field. This noise would disturb data communication between devices and even destroy the device. Photocoupler can transform input electrical signal into optical signal at first, and then transform the optical one into output electrical signal, which realizes entirely electrical isolation with no influence on data communication. So photocoupler becomes the perfect solution for fieldbus isolation. Currently, the most part of photocouplers on the market are imported. Therefore, to design a high speed digital photocoupler has a broad market prospect. In addition, the photocoupler is widely used in the military and aerospace fields. In this field, photocoupler characteristics are influenced strongly by radiation, such as reliability degrading, service life decreasing and even loss of function. A radiation hardend high speed digital photocoupler is more apealling in the market. High speed digital photocoupler is composed of high speed LED and optical reciever chip. Optical reciever chip is the most important modules, and its performance directly determines the performance of the photocoupler. That means to design a radiation hardened high speed photocoupler is to design a radiation hardened optical receiver chip.This thesis introduces the basic theory of the data transimission of photocoupler, the working principle of sub modules and the method of Radiation Hardening by Design(RHBD). Based on this, a 10 MBd radiation hardened optical receiver chip has been designed at first. And then, two higher speed ones with transmission rate 30 MBd was designed by using differential photodetector and analog equalizer. In this process, the method of photodetector model establishment by using Matlab and Verilog-A, the transimpedance amplifier which bandwidth is extended by local negative feedback, the method to determine the parameters of equalizer using sisotool and Enclosed-gate Layout Transistor(ELT) cell library establishment basing on standard process library, is mainly discussed.Finally, the 10 MBd radiation hardened photocoupler achieves: input high current range is 2~6mA, quiescent current is 4.2mA, propagation dalay time to high\low output level is 39\36ns at the condition that load resistor is 350? and capacitance is 15 pF, and pulse width distortion is less than 15 ns. The ELT and Dynamic threthold MOS(DTMOS) improved the antiradiation feature. The 30 MBd photocoupler with analog equalizer achieves: input high current range is 2~6mA, quiescent current is 4.9mA, propagation dalay time to high\low output level is 21\20ns, and pulse width distortion is less than 15 ns. The one with differential photodetector achieves: input high current range is 6~18mA, quiescent current is 3.7mA, propagation dalay time to high\low output level is 23\16ns, and pulse width distortion is less than 30 ns.