Wireless sensing by means of passive multistandard RFID tags

Abstract

This paper presents a generic sensor interface built in a 0.13 µm CMOS process capable of being applied in passive HF & UHF RFID Tags without any additional power supply. The sensor interface contains an ultra low-power successive approximation ADC that uses the capacitive charge redistribution technique for its integrated DAC. An on-chip temperature sensor and up to three additional sensor signals can be applied to the ADC. A conversion rate of 100 kSps is reached while consuming less than 1.5 µA at 0.9 Volt supply voltage.

The Roots, Rules, and Rise of RFID

“…A successive approximation architecture is best for data conversion, as there is no need for very high conversion rates and it consists of only a few components. By choosing lowpower techniques like time-domain comparison, charge-scaling, and charge-redistribution for the capacitive digital to analog conversion (DAC) and by switching bias currents wherever possible, the power consumption of a successive approximation register ADC can be decreased down to the microwatt-domain [17], [18]. When operating at low conversion rates this even decreases to several hundred nanowatts.…”

Design of a low-voltage reference circuit with reconfigurable temperature range for RFID applications

“…Using the reference voltage as a reference for a low-voltage ADC the resulting value should be as high as possible to achieve a sufficient input range for the digitization [7]. The maximum value VRe j ,max is limited by the minimum supply voltage V D Dmin at which the circuit works and the respective minimal drain-source voltage drop VDS,P3(sat) of the output current source P3 for operating in saturation state (Fig.…”