Bandgap reference exploiting mechanical stress
S.S. Chavan · 2020
A low voltage CMOS Bandgap reference requiring a supply >= 0.85 and operating in the range of -20°C to 100°C with a temperature coefficient of 42ppm/°C and a line sensitivity of 0.63%/V is introduced in this report. The schematic design draws a current of 700nA at 25°C. The novelty of the reference is usefulness of the decrease in the material bandgap of silicon in a PN junction diode as a result of mechanical pressure or stress induced by the surrounding STI structures in 65nm technology. Two diodes with a bandgap difference of 18mV are used in this design after details about the measurements of such diodes and calculation of change in bandgap due to stress is studied. The concept of a ”Downshifted PTAT” voltage obtained as a result of decrease in bandgap is the core of this design.