A Digitally Trimmable Wide Temperature Range 0.35-µm CMOS On-Chip Precision Voltage Reference

Inhalt:
This paper presents a precision reference voltage source for use in integrated smart-sensor frontends that can operate in an extended ambient temperature range from -40 °C to 150 °C. The reference source is based on a bandgap core whose residual temperature sensitivity is reduced further by means of curvature compensation. The desired output voltage of 2:56 V is derived from the bandgap voltage using a digitally trimmable LDO. Trim settings can be programmed via a test interface and stored permanently in an EEPROM. The reference source was designed as a component of a complex temperature sensor interface ASIC using a commercial 0.35-µm CMOS process. Measurements of fabricated devices yielded temperature coefficients of the reference voltage as low as 2:6 ppm/°C in the range from 0 °C to 90 °C and 4:1 ppm/°C in the entire operating temperature range. Index Terms — Voltage reference, bandgap, wide temperature range, curvature compensation, trimming