Monolithic Integration Of Front-end Amplification Circuit For1.25Gbps Optical Receiver

According to China’s "12th Five-Year" Development Plan, China will add25million FTTH(fiber-to-the-home) subscribers during the "12th Five-Year", the FTTHcoverage rate of new buildings in cities will reach more than60%. The major factorthat constrains the development of FTTH is the high constructing and maintainingcosts, while the cost of optical receiver that plays a role of core equipment in FTTHoccupies1/3of the total expenditure. The OEIC technology, as the key means ofreducing the costs, has broad application prospects and urgent practical needs.This dissertation realized the monolithic integration of a front-endtransimpedance amplifier(TIA) and a limiting amplifier(LA) for1.25Gbps opticalreceiver based on Chartered0.35μm standard CMOS process. Moreover, a LowDropout Linear Regulator(LDO), a loss of signal detector(LOS), and a receive signalstrength indicator(RSSI) has also been integrated in the chip, which makes the chipbe a multifunctional one that can meet the mainstream requirements of optial recieverat the commercialized bit rate of1.25Gbps.The data path part adopts the fully-differential structure in order to suppress thecommon mode disturbance from substrate-noise, power-supply-ripple etc.. The GBWof the system has been improved by several broad band techniques, such as the RGCstructure, active feedback etc. which made the system gain and bandwidth reached106dBΩ and1.23GHz respectively. The system’s dynamic input range is expanded bythe AGC circuit that makes the chip can output constant swing450mVpp signalstably when input singal changes from10μA to1mA. Because of the monolithicintegration of TIA and LA, the whole power and area costs are reduced, the core areaof the chip is550μm×470μm，and the system power consumption is192mW.More over this chip has integrated a low dropout regulator(LDO) internally as thepower supply of the photodiode, which is in order to reduce disturbance from thesupply ripple. Loss of signal detector(LOS) and receive signal strengthindicator(RSSI) are also provided in this design, which make the chip closer to theneeds of market.