A 14-b BW /Power Scalable Sensor Interface with a Dynamic Bandgap Reference
Zhong Tang (Vango Technologies Inc., Hangzhou)
Yuyan Liu (Vango Technologies Inc., Hangzhou)
Pengpeng Chen (Vango Technologies Inc., Hangzhou)
Haining Wang (Vango Technologies Inc., Hangzhou)
Xiaopeng Yu (Zhejiang University - Hangzhou)
K.A.A. Makinwa (TU Delft - Microelectronics)
Nick Nianxiong Tan (Vango Technologies Inc., Hangzhou)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
This article presents a 14-bit fully dynamic sensor interface that consists of a switched-capacitor (SC) ΔΣ modulator and a dynamic bandgap reference (BGR). The BGR is implemented by summing the proportional to absolute temperature (PTAT) and complementary to absolute temperature (CTAT) outputs of two PNP-based capacitive DACs. At the sampling rate, the DAC capacitors are pre-charged to the supply and then discharged for a fixed period via PNPs, thus biasing them and simultaneously sampling their base-emitter voltages. By using the modulator's first integrator to sum the DAC outputs, a dynamic BGR can be realized, which does not need additional reference buffers or decoupling capacitors. To make the system fully dynamic, the modulator itself is based on capacitively biased (CB) floating inverter amplifiers (FIAs). Implemented in a standard 130-nm CMOS process, the sensor interface occupies an area of 0.2 mm2. It achieves an SNDR of > 84.5 dB over a scalable bandwidth (BW) ranging from 98 Hz to 5.9 kHz while consuming 1.7-50.8 μW. Furthermore, by employing a time-domain temperature-compensation scheme, it achieves a batch-trimmed gain error of ± 0.26% from -40°C to 125 °C.