System in package of bandgap voltage reference circuit with sub-1-V operation in CMOS for communication control and BioMedical applications

Abstract

A system in package low-voltage bandgap voltage reference (BGR) implemented in 90 nm CMOS process is designed, simulated, and measured. The bandgap reference circuit is optimized before fabrication in order to generate a temperature independent voltage reference. The load of output stage is a MOSFET active device controlled by the voltage reference so that the output accuracy increases. The overall circuit consists of a bandgap core circuit, an operational amplifier (op amp), and a bias circuit with start up function. The simulated power supply rejection ratio (PSRR) and start-up circuit reaction time are 29 dB and approximately 2.5 us, respectively. Measured result of temperature coefficient (TC) achieves a 163 PPM/oC which is translated to the variation of the reference voltage is only 10 mV over the temperature ranges of 0 to 90°C. With a 1.2 V supply voltage, the measured output voltage is 786 mV at room temperature and the power consumption is 2.1 mW. The chip area including dummy wiring, decoupling capacitor and pads is only 0.133 (0.449 x 0.297) mm 2 . The SIP CMOS can support communication control and biomedical networking.Index Terms-bandgap voltage, bandgap reference, temperature coefficient, BioMedical applications.