Research And Design Of The Normal Temperature And Low Temperature Readout Circuits

With the rapid development of semiconductor technology,the noise of the readout circuits is getting lower and lower.Low noise readout circuits can be used in physical sensors and biomedical wireless sensors,This paper mainly introduces these amplifies that can amplify weak signals and readout circuits with low noise performance.At different temperatures,the noise performance of the readout circuits and the emphasis of the design are also different.In this paper,two kinds of readout circuits are designed:normal temperature readout circuit and low temperature readout circuit.Normal temperature readout circuit uses TSMC 0.18?m CMOS process,pre amplifier with folded cascode structure can achieve high gain,and using the structure of source degeneration resistor significantly to reduce the flicker noise of the system.The DC bias used voltage source to reduce the input noise.In the aspect of layout design,the technology of common center and deep N trap are used to reduce the mismatch and noise interference.After the simulation,the equivalent input noise voltage of normal temperature readout circuit can achieve 9.519nV/V Hz@10kHz,when the chip is bonded on PCB board,the equivalent input noise voltage of normal temperature readout circuit can achieve 10.3nV/V Hz@10kHz.Low temperature readout circuit uses IBM 8HP 0.13pm SiGe BiCMOS process,the readout circuit works in liquid helium heat preservation box,and the temperature is 4.2K(270 degrees below zero or so).Because the working temperature nears absolute zero,so the readout circuit has very low noise.But,at present,there is no simulation model of Candence simulation software in 4.2K.For the normal work of the circuit under low temperature,this paper analyzed two kinds of methods of the circuit bias at low temperature:static resistance bias bias structure and current structure.In the post simulation,the circuit can work normally with the change of temperature,and the gain can be adjusted by changing the bias current and bias voltage...