1
Features
Contactless Read/Write Data Transmission
992-bit EEPROM User Programmable in 31 Blocks
32 Bits
Inductively Coupled Power Supply at 125 kHz
Basic Component: R/W IDIC
Transponder IC
Built-in Coil and Capacitor for Circuit Antenna
Starts with Cyclical Data Read Out
Typical < 50 ms to Write and Verify a Block
Modulation Defeat (for EAS)
Direct Access to Each Block
Configurable POR Delay
Write Protection by Lock Bits
Malprogramming Protection
Configurable Options:
Bit Rate [Bit/s]: RF/16 and RF/32
Modulation: Manchester
POR Delay: 1 ms/65 ms
Maximum Block: 0, 1, 1 to 2, 1 to 3, 1 to 4, .... 1 to 31
Applications
Industrial Asset Management
Process Control and Automation
Installation and Medical Equipment
Description
The TK5552 is a complete programmable R/W transponder that implements all impor-
tant functions for identification systems. It allows the contactless reading (uplink) and
writing (downlink) of data which are transmitted bi-directionally between a read/write
base station and the transponder. It is a plastic cube device which accomodates the
IDIC transponder IC and the antenna is realized as an LC circuit. No additional exter-
nal power supply is necessary for the transponder because it receives power from the
RF field generated by the base station. Data is transmitted by modulating the ampli-
tude of the RF field (uplink mode). The TK5552 can be used to adjust and modify the
ID code or any other stored data, e.g., rolling code systems. The on-chip 1056-bit
EEPROM (32 blocks, 33 bits per block) can be read (uplink) and written (downlink)
blockwise from the base station. The blocks can be protected against overwriting. One
block is reserved for setting the operation modes of the IC.
Read/Write
Transponder
TK5552
Rev. 4698ARFID04/03
2
TK5552
4698ARFID04/03
Figure 1. Transponder and Base Station
General
The transponder is the mobile part of a closed coupled identification system (see Figure
1), where the read/write base station incorporates a reader IC such as the U2270B, and
the read/write transponder is based on the transponder IDIC.
The transponder is a plastic cube device consisting of the following parts:
The transponder antenna, realized as a tuned LC circuit
The read/write IDIC (transponder IC) with EEPROM
Transponder Antenna
The antenna consists of a coil and a capacitor for tuning the circuit to the nominal carrier
frequency of 125 kHz. The coil has a ferrite core to improve the distance of read (uplink)
and write (downlink) operations.
Read/Write IDIC
The read/write Transponder IDIC is part of the transponder TK5552. The data is trans-
mitted bi-directionally between the base station and the transponder. The transponder
receives power via a single coil from the RF signal generated by the base station. The
single coil is connected to the chip and also serves as the IC's bi-directional communica-
tion interface.
Data transmission is done by modulating the amplitude of the RF signal. Reading
(uplink) occurs by damping the coil by an internal load. Writing (downlink) occurs by
interrupting the RF field in a specific way. The TK5552 transponder operates at a nomi-
nal frequency of 125 kHz. Different bit rates and encoding schemes are available.
The on-chip 1056-bit EEPROM (32 block, 33 bits each) can be read (uplink) and written
(downlink) blockwise from the base station. The blocks can be protected against over-
writing by using lock bits. One block is reserved for setting the operation modes of the
IC.
See section "Transponder IC Read/Write Identification IC with 1k-bit Memory".
Transponder IC
Transponder TK5552
RF field
Data
Power
Base station
(1)
Coil
C
(1) For a short distance U2270B read/write IC with MARC4 (see Figure 12)
Transponder IC + coil + C in plastic cube
3
TK5552
4698ARFID04/03
Figure 2. Block Diagram Transponder IC
Mode
register
Analog front end
(rectifier, regulator, clock extractor, ESD protection)
POR
Bit decoder
Bit rate generator
EEPROM memory
Start-up
delay
Charge
pump
Controller
I
n
p
u
t
r
e
g
i
s
t
e
r
M
o
d
u
l
a
t
o
r
C
l
o
c
k
-
B
C
l
o
c
k
-
A
Absolute Maximum Ratings
Parameters
Symbol
Value
Unit
Operating temperature range
T
amb
-25 to +75
C
Storage temperature range
T
stg
-40 to +125
C
Maximum assembly temperature, t < 5 min.
T
ass
170
C
Magnetic field strength at 125 kHz
H
pp
1000
A/m
Operating Characteristics Transponder
T
amb
= 25
C, f = 125 kHz, RF/32 and Manchester if not otherwise noted
Parameters
Test Conditions
Symbol
Min.
Typ.
Max.
Unit
Inductance
L
4
mH
Resonance frequency
LC circuit, H
PP
= 12 A/m
f
r
119
125
131
kHz
Magnetic Field Strength (H)
Maximum field strength where tag
does not modulate
No influence on other tags in the field
H
pp not
4
A/m
Minimum Field Strength
Uplink/downlink mode
H
pp 25
12
A/m
Programming mode
H
pp 25
18
A/m
Data retention EEPROM
t
retention
10
Years
Programming cycles EEPROM
100,000
Maximum field strength
H
pp max
600
A/m
4
TK5552
4698ARFID04/03
Figure 3. Typical TK Range of Resonance Frequency
Figure 4. Degree of Modulation Measurement
Figure 5. Typical Behaviour of Resonant Frequency, Degree of Modulation and
Quality Factor versus Field Strength (by RF/32, Manchester)
-4
-3
-2
-1
0
1
2
3
4
-30
-20
-10
0
10
20
30
40
50
60
70
80
Temperature (C)
TK
of R
esonance Freque
nz
y (%)
V2
V1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0
25
50
75
100
125
H
PP
(A/m)
m (1)
Quality factor (Q)
Resonant frequency
Degree of modulation (m)
20
125
25
126
30
127
35
124
15
123
10
122
5
121
120
0
Q (1
)
fr
es (
k
Hz)
5
TK5552
4698ARFID04/03
Measurement Assembly
All parameters are measured in a Helmholtz arrangement, which generates a homoge-
nous magnetic field (see Figure 6 and Figure 7). A function generator drives the field
generating coils, so the magnetic field can be varied in terms of frequency and field
strength.
Figure 6. Testing Application
Figure 7. Testing Geometry
Downlink Operation
The write sequence (downlink mode) of the TK5552 is shown in Figure 10. Writing data
into the transponder occurs by interrupting the RF field with short gaps. After the start
gap the standard op code (11) is followed by the lock bit. The next 32 bits contain the
actual data. The last 5 bits denote the destination block address. If the correct number of
bits has been received, the actual data is programmed into the specified memory block.
SUBTRACTOR
FUNCTION
GENERATOR
OUTPUT
VOLTAGE
AMPLIFIER
1:10
FIELD GENERATING
COILS ( IN PHASE )
REFERENCE COIL ( IN PHASE )
SENSING COILS ( IN PHASE )
REFERENCE COIL
( IN PHASE )
TK5552
30mm
15mm
2mm
5mm
24mm
60mm
SENSING COIL
REFERENCE COIL
FIELD GENERATING COIL
SENSING COIL
REFERENCE COIL
FIELD GENERATING COIL
TK5552
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