Analysis and Validation of Low-Frequency Noise Reduction in MOSFET Circuits Using Variable Duty Cycle Switched Biasing

Abstract

In MOS transistors, low-frequency noise phenomena such as random telegraph signal (RTS), burst, and flicker or 1/f noise are usually attributed to the random nature of the trap state of defects present at the gate Si-SiO2 interface. In a previous work, theoretical modeling and analysis of the RTS and 1/f noise in MOS transistor was presented and it was shown that this 1/f noise power can be reduced by decreasing the duty cycle (D) of switched biasing signal. In this paper, an extended analysis of this 1/f noise reduction model is presented and it is shown that the RTS noise reduction is accompanied with shift in the corner frequency (fc) of the 1/f noise and the value of shift is a function of continuous ON time (Ton) of the device. This 1/f noise reduction is also experimentally demonstrated in this paper using a circuit configuration with multiple identical transistor stages which produce a continuous output instead of a discrete signal. The circuit is implemented in 180 nm standard CMOS technology, from UMC. According to the measurement results, the proposed technique reduces the 1/f noise power by approximately 5.9 dB at switching frequency (fs) of 1 KHz for 2 stage, which is extended up to 16 dB at fs of 5 MHz for six stage configuration.

Keywords

• Low-frequency noise
• RTS noise
• f noise%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> 1/<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">f</italic> noise
• stochastic process
• CMOS image sensors
• random process