3.4 A 14b 98Hz-to-5.9kHz 1.7-to-50.8 μ W BW/Power Scalable Sensor Interface with a Dynamic Bandgap Reference and an Untrimmed Gain Error of ± 0.26 % from −40°C to 125°C

To accommodate different use cases, the bandwidth (BW) and power dissipation of sensor interfaces for IoT applications should be highly scalable. For example, Coulomb counting requires precision current sensors with low BW and microwatt power for extended battery life, while AC battery impedance measurements require sensors with much higher BWs [1]. There is thus a need for precision ADCs that are BW/power scalable. Although SAR ADCs can easily scale their BW and power by changing their sampling frequency, they typically have a moderate resolution [2]. To achieve higher resolution, BW/power-scalable Delta-Sigma ADCs can be used [3]. In both cases, however, the ADC will typically be combined with an external band-gap reference (BGR) (Fig. 3.4.1 top left), which, in turn, requires power-hungry reference buffers and/or large decoupling capacitors to drive the ADC.