SR176 Datasheet, PDF (2/5 Pages) STMicroelectronics – 13.56 MHz Short Range Contactless Memory Chip 176 bit USER EEPROM and 64-bit Unique ID

SR176
SUMMARY DESCRIPTION
The SR176 is a contactless memory, powered by
an externally transmitted radio wave. It contains
176 bits of user EEPROM, fabricated with STMi-
croelectronics CMOS technology. The memory is
organized as 16 blocks of 16 bits, of which 11
blocks are user accessible.
The SR176 is accessed via the 13.56MHz carrier.
Incoming data are demodulated and decoded
from the received Amplitude Shift Keying modula-
tion signal (ASK). The modulation index of this sig-
nal is 10%. Outgoing data are generated by load
variation using Bit Phase Shift Keying (BPSK) of a
847kHz subcarrier. The Data transfer rate be-
tween the SR176 and the reader is 106kbit/s in
both reception and emission modes.
The SR176 follows the ISO 14443 part 2 type B
recommendation for radio frequency power and
signal interface.
Figure 2. Logic Diagram
SR176
176 bit
User
EEPROM
Power
Supply
Regulator
ASK
Demodulator
BPSK
Load
Modulator
AC1
AC0
AI04995
The SR176 is principally designed for short range
applications, such as in object identification, that
need a low cost and non-reusable product. The
SR176 does not include any anti-collision mecha-
nism, but does include a simple selection mecha-
nism to cope with cases where more than one tag
is present, within the range of the Reader, at the
any one time.
Table 1. Signal Names
AC1
Antenna Coil
AC0
Antenna Coil
The SR176 contactless EEPROM offers read and
write random access in block mode. One block is
composed by 16 bits. The device has an instruc-
tion set containing seven commands:
s READ_BLOCK
s WRITE_BLOCK
s INITIATE
s SELECT
s COMPLETION
s PROTECT_BLOCK
s GET_PROTECTION.
The SR176 is divided into two major areas: the
unique identifier (UID) and the User EEPROM.
The UID is a 64-bit unique identifier written by ST
during product manufacturing. The User EEPROM
is divided into areas which can be write-protected
so that they behave as ROM. The write protection
is activated using an OTP lock bits register. It is
possible to program the SR176 4-bit chip_ID used
by the SELECT command. Its default value is fixed
at the value 0 (0000_b) by ST. When correctly set,
up to sixteen SRIX4Ks can be selected individual-
ly.
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