An Ultra-Low-Power RFID/NFC Frontend IC Using 0.18 μm CMOS Technology for Passive Tag Applications

Abstract

Battery-less passive sensor tags based on RFID or NFC technology have achieved much popularity in recent times. Passive tags are widely used for various applications like inventory control or in biotelemetry. In this paper, we present a new RFID/NFC frontend IC (integrated circuit) for 13.56 MHz passive tag applications. The design of the frontend IC is compatible with the standard ISO 15693/NFC 5. The paper discusses the analog design part in details with a brief overview of the digital interface and some of the critical measured parameters. A novel approach is adopted for the demodulator design, to demodulate the 10% ASK (amplitude shift keying) signal. The demodulator circuit consists of a comparator designed with a preset offset voltage. The comparator circuit design is discussed in detail. The power consumption of the bandgap reference circuit is used as the load for the envelope detection of the ASK modulated signal. The sub-threshold operation and low-supply-voltage are used extensively in the analog design—to keep the power consumption low. The IC was fabricated using 0.18 μm CMOS technology in a die area of 1.5 mm × 1.5 mm and an effective area of 0.7 normalmm2. The minimum supply voltage desired is 1.2 V, for which the total power consumption is 107 μW. The analog part of the design consumes only 36 μW, which is low in comparison to other contemporary passive tags ICs. Eventually, a passive tag is developed using the frontend IC, a microcontroller, a temperature and a pressure sensor. A smart NFC device is used to readout the sensor data from the tag employing an Android-based application software. The measurement results demonstrate the full passive operational capability. The IC is suitable for low-power and low-cost industrial or biomedical battery-less sensor applications. A figure-of-merit (FOM) is proposed in this paper which is taken as a reference for comparison with other related state-of-the-art researches.

VLSI Implementation of Area and Power Efficient Digital Control Circuit for HF RFID Tag Chip

“…In recent years, several similar designs can be found in Refs. [8,[19][20][21][22][23]], yet the designs in Refs. [8,22,23] cannot provide enough information especially area information to compare with each other.…”

Factors Affecting the Synthesis of Autonomous Sensors with RFID Interface

“…On the other hand, transponders can include stand-alone sensors (with analog or digital output) that are attached to low power microcontrollers with RFID interfaces. They can be based on two different constructions: a RFID frontend integrated with a low power microcontroller [39,43] (Figure 3c) or on a RFID chip which provides a voltage output V OUT for external circuitry [44,45] (Figure 3d). Both of them suffer from a lack of enough energy and can work only in a strong electromagnetic field.…”

A CMOS Programmable Fourth-Order Butterworth Active-RC Low-Pass Filter

“…The ultra-high frequency (UHF) radio frequency identification (RFID) technology has been widely applied in many fields because of its advantages such as wide readable range, large information storage capacity, long recognition distance, and strong space penetration [1][2][3]. Within a direct-conversion UHF RFID reader transceiver, the analog low-pass filter (LPF) is one of the critical blocks for analog baseband signals.…”