Module-2c: Two Port Noise Modelling 20 July 2018 16:40 Shot Noise - PDF document

Module-2c: Two Port Noise Modelling 20 July 2018 16:40 Shot Noise vs. Flicker Noise Simple Temperature Sensor Modules Page 1

Reference: Prof. Ali Niknejad, Two Port Noise Analysis, 2015 Why do we refer noise to input? Modules Page 2

noise Why do we split it into two sources? Procedure to determine input referred noise: 1. Identify all independent noise source (transistors, resistors, diodes etc.) 2. Determine transfer functions from each noise source to output 3. Determine total output noise v_nout or i_nout (sum of squares) 4. Divide by transfer function from v_in to v_out or i_in to v_out etc. Example Modules Page 3

Sensor Noise vs. Front-End Noise: Which should be dominant? Modules Page 4

Module-2d: SNR and SNR Improvement Techniques 19 July 2018 10:35 SNR Definition Example: What is the right SNR to choose for continuous signals? Straight-forward ways to increase SNR • Increase signal ○ Higher sensitivity sensor --> costly ○ Higher supply voltage --> greater amplitude --> more power (VDD*ID) Modules Page 1

• Reduce noise ○ Increase gm --> higher power or larger area ○ Decrease bandwidth? Arraying of Sensors Example Modules Page 2

https://www.bsse.ethz.ch/bel/research/cmos-microsystems/microelectrode-systems/ _jcr_content/par/fullwidthimage/image.imageformat.fullwidth.340125254.png Prof. Andreas Hierlemann's Group Simulating noise (Discrete samples) Modules Page 3