Design Of High Precision Bandgap Voltage Reference

Reference is the most important cell in analog integrated circuits. It outputs high-precision voltage or current reference for other functional modules. The output of reference is independent of temperature, supply voltage, process and load. With the rapid development of semiconductor technology, there is a challenge to attain higher performances of the circuits in recent years. Reference as the core of circuits, its performance determines directly the steady of systems. Therefore, the design of high-precision reference is particularly important to analog integrated circuits.In order to meet the requirements of the high performance system in the future, the precision, temperature drift, power supply rejection ratio were optimized in this paper. A high precision bandgap voltage reference with low temperature coefficient was presented, based on bipolar process. On the basis of Brokaw bandgap reference, a temperature-dependent poly resistor was used to achieve high-order curvature compensation, which greatly reduced the temperature coefficient of the reference. Negative-feedback loop was introduced to improve the power supply rejection ratio of reference, and trimming resistive circuits were designed to improve the precision of reference voltage. The test results indicated that with the power supply of 15 V, the temperature coefficient of 12ppm/? and the reference output voltage of 2.5V±6mV were achieved within the range from-55? to 125?. Furthermore,the bandgap reference had PSRR of-105 dB at low frequence, and the load current can be as high as 10 mA with the current consumption of less than 1.5mA.