A high-order temperature-compensated bandgap reference without operational amplifiers

This paper proposes a new op-amp-free BJT reference voltage source based on high-order compensation using subthreshold MOSFETs. The circuit is implemented using the DB-HITEC 0.18μm BCD process and generates a stable 1.25V output voltage with a 2.5V supply voltage. Over a temperature range of -40 to 125°C, the minimum temperature coefficient is 2.48×10⁻⁶/°C, the maximum temperature coefficient is 3.7×10⁻⁶/°C, the output voltage deviation is 0.5mV, and the power supply rejection ratio is 75dB.Due to its low temperature coefficient (T.C.) and high power supply rejection ratio, the circuit proposed in this paper will be very useful for sensor circuits with stringent requirements or other analog circuits that demand high precision applications.