EM4006
Factory reserved bits
These 9 bits are reserved. Default value is 00Bhex.
IC name bits
They contains the 3 last characters device name. For this
device, the value is 006hex.
Customer ID bits
This field contains a code which is defined by EM
Microelectronic-Marin S.A. For standard version, the code
is 0001hex.
ID code bits
This field is programmed from a counter in that way that
each device is unique.
Cyclic redundancy check
The shift register is reset to all zero with each Stop Bit.
CRC code is calculated on 64 data bits. The CRC code is
calculated according to CCITT / ISO 3309 - 1984
standards. See figure 5 for principle block schematic and
generating polynomial of the CRC code.
Start and stop bits
Start bit is set to logic 1 and stop bit is set to logic 0.
CRC Block Diagram
SERIAL QUOTIENT
X5
X12
FEEDBACK
BEFORE
SHIFT
X16
15 14 13 12 11
MSB
10
9
8
7
6
5
4
3
2
1
0
LSB
BCC REGISTER
x
=
BCC(Block Check Characters) REGISTER STAGE
data input
=
EXCLUSIVE - OR
CRC-CCITT GENERATING POLYNOMIAL = X16 + X12 + X5 + X0
Fig. 5
RF Interface
Resonant capacitor, Rectifier, Limiter and Modulator
Switch form the unit which is interfacing to the incoming
RF signal. These blocks are interdependent so they are
developed as unit. They interface to the antenna which
typical characteristics are:
L
S
≈
1400 nH
R
S
≈
3 Ohms
30 < Q < 40 at 13.56 MHz.
Resonant Capacitor
The capacitor value is adjusted by laser fusing. It can be
trimmed by 1pF steps to achieve the absolute value of
94.5pF typically. This option, which is available on
request, allows a smaller capacitor tolerance over the
whole production.
Rectifier and Limiter
A full wave rectifier (Graetz Bridge) is used to provide
supply voltage to the IC. The reverse breakdown of the
diodes is also used to protect the IC from overvoltages.
Copyright
2001, EM Microelectronic-Marin SA
5
www.emmicroelectronic.com
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
