Linearity Boosting Technique Analysis for a Modified Current-Mode Bandgap Reference

This paper presents a detailed analysis of an e ffective method to improve the linearity and, consequently, the temperature insensitivity of the output characteristic of current processing based bandgap references. The described technique is shown to be successful on a circuit which generates a temperature-invariant current of approximately 1 mu A which has been designed and extensively simulated in a standard 130-nm CMOS process in the -40 degrees C to 125 degrees C temperature range. The circuit nominal supply voltage is 1.5 V and it has a total power consumption of about 5 mu W. The analyzed linearity boosting technique, applied to the proposed circuit, provides a temperature sensitivity of the output current as low as 1.7 ppm/degrees C in the considered range, making it suitable for a lot of di fferent precision applications that require a highly stable current signal with respect to temperature.