All-CMOS Precision Temperature Sensors

A CMOS Image Sensor With Thermal Sensing Capability and Column Zoom ADCs

“…Reference [5] proposes a low power 10 bit 20 MHz delta-sigma ADCs using an inverter based opamp for its delta-sigma modulator. SAR has been proposed to assist the delta-sigma ADC in its loop [6]; however, for DC-input ADCs, it is more energy and time efficient to locate the SAR outside instead of inside the deltasigma modulator [6]- [8], e.g., a zoom ADC. In contrast to the aforementioned publications [1]− [8], this paper has the following features: (1) Using a 4 bit UCA SAR to assist an incremental 2 nd order 13 bit DSADC, it achieves 9 dB better SNR while maintaining the conversion speed, or twice sampling rate while keeping its SNR; in other words, a higher dynamic range, compared to a DSADC only counterpart, being experimentally verified.…”