Design and Simulation of 140 dB Dynamic Range and 20 uVrms Readout Noise CMOS Image Sensor

This paper provides the design, simulation and implementation of a very wide dynamic range and a low readout noise CMOS image sensor (CIS) with high sensitivity by using a diode connected transistors in parallel with floating diffusion node and sensor output. The sensor is simulated, designed and implemented in a 130 nm CMOS technology using cadence tool. The area of the proposed pixel reaches to 3 um x 3 um and consists of seven NMOS transistors and one capacitor. The readout circuit has the following parameters as very low output noise of 20 uVrms with a 5 MHz bandwidth for pixel circuitry. Power dissipation of 10 uW was achieved at an operation voltage of 1.6 V for pixel circuitry. The proposed sensor has good features of low noise and a 140 dB wide dynamic range due to the diode connected transistor configuration that has been used. This paper provides the effect of adding a diode connected transistors M7 and M8 on an increasing dynamic range of CMOS image sensor to 140 dB and reducing its readout noise to 20 uVrms. Also, this paper provides a mathematical simulation of noise model of CIS using Matlab and cadence. Keywords— CMOS image sensor (CIS), wide dynamic range (WDR), bandwidth, readout noise, diode connected transistor