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MPC-WORKSHOP JULI 2012
Realization of an RFID Front End IC for ISO 15693
Standard in UMC CMOS 0.18 µm Technology
Mayukh Bhattacharyya, Tobias Volk, Andreas Kreker, Benjamin Dusch, Dirk Jansen
Abstract—The RFID Front End manages communication
and protocol according to the requirements
of the ISO 15693 standard. It is developed
for passive as well as semi-passive applications and
interfaces to standard microprocessors, which can
be programmed to capture data or execute commands
in a general manner. The current consumption
of the front end is below 50 µA, making it
suitable for low power applications. This paper
covers the analog part only. The reader generates
an ASK-modulated signal, which is demodulated
and provided as a digital signal. The 13.56 MHz
clock is recovered and a signal, which detects the
existence of RF field, is used. For the back channel,
classical load modulation is implemented. There
are further elements for passive applications integrated,
a low drop out regulator LDO with adjustable
output voltage and a reference voltage source
with a bandgap circuit. This makes the front end
IC suitable for energy harvesting sensor applications.
Index Terms—RFID (Radio frequency identification
device), RF–field passive system, energy harvesting,
bandgap reference, low drop out regulator,
ASK demodulator.
I. INTRODUCTION
RFID technology is regarded as one of the evolutionary
technology of the 21st century. It was initially
used as a replacement for the existing barcode systems,
over the years RFID has evolved as one of the
key technologies for device identification. In addition
to its original intention, the technology of bidirectional
data communication available with RFID can again be
used for ultra-low power or even passive micro sensor
systems. There are applications in transportation,
manufacturing, biomedical [1], environmental management,
safety and security systems. The advantage
of using an established standard, with low cost reader
systems available in the market or even integrated into
the newest mobile phones makes short range telemetry
Mayukh Bhattacharyya, mayukh.bhattacharyya@hs-offenburg.de, Tobias
Volk, tobias.volk@hs-offenburg.de, Andreas Kreker, andreas.kreker @hsoffenburg.de,
Benjamin Dusch, benjamin.dusch @hs-offenburg.de, and Dirk
Jansen, d.jansen@hs-offenburg.de, are with University of Applied Sciences-
Offenburg, Badstrasse 24, 77652 Offenburg.
Figure 1: Inductive coupling for an RFID reader transponder
system.
Figure 2: Front end with external devices.
cheap and ubiquitous available.
A typical RFID system consists of a reader and a
transponder; the reader may be a smart phone or a host
computer, connected to a network [2]. The tag consists
of the front end (FE), which has an analog part and a
digital part as well as a back end, which may be a data
capturing system like a microprocessor, coupled with
a sensor and external memory. In a fully developed
tag, all these units will be integrated into one IC with
only the sensors separated, making a so called “smart
tag”, running optimally by harvesting the supply energy
from the RF field.
Semi-active sensor tags contain an own supply,
mostly a battery, because they have to be active without
the connection to the reader, i.e. for collecting data
at predefined intervals. These kinds of sensors have
again several applications [3], the RFID interface is
only used for convenient and extreme low power read
out. The RFID reader/ transponder system can be
typically defined as a loosely coupled transformer,
where the antenna of the RFID reader acts as the primary
and the antenna of the transponder acts as the
secondary winding as shown in Figure 1. A typical
RFID front end with external devices is shown in
figure 2.
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