EMI resisting MOSFET-only voltage reference based on ZTC condition

Abstract

Electromagnetic interference (EMI) can significantly degrades the performance of analog circuits, including voltage and current references, especially due to their limited power supply rejection. An EMI resistant MOSFET-only voltage reference is herein proposed, based on the MOSFET zero temperature coefficient (ZTC) vicinity condition. The ZTC condition is analytically derived through a continuous MOSFET model that is valid from weak to strong inversion, also a design methodology is presented. The final circuit is designed in a 130 nm process and occupies around 0.0075 mm$$^{2}$$2 of silicon area while consuming just 10.3 $$\upmu$$μW. Post-layout simulations present a 395 mV reference voltage ($$V_{REF}$$VREF) with a effective temperature coefficient ($$TC_{eff}$$TCeff) of 146 ppm/°C, for a temperature range from ź55 to +125 °C. A 4 dBm (1 $$V_{pp}$$Vpp amplitude) EMI source injected into the power supply, according to direct power injection standard [1], results in a maximum DC Shift and peak-to-peak ripple of ź1.7 % and 35.8 m$$V_{pp}$$Vpp, respectively. The proposed voltage reference has already been fabricated and is under preliminary measurements, presenting a maximum variation of 21 mV for a 600 mV minimum supply.