Texas Instruments 2000 series User manual

High Performance LF Remote Antenna Radio Frequency Module RI-RFM-008B December
1999
1
Series 2000 Reader System
High Performance Remote Antenna-Reader Frequency Module
RI-RFM-008B
A
ntenna Tuning Boar
d
RI-ACC-008B
Reference Guide
11-06-21-047 February 2002

High Performance RA-RFM RI-RFM-008B February 2002
2
Fourth Edition – July 2001
This manual describes the TI-RFID High Performance Remote Antenna-Reader
Frequency Module RI-RFM-008B hereafter referred to as the RA-RFM and the
Antenna Tuning Board RI-ACC-008B.
Important Notice
Texas Instruments reserves the right to change its products or services or to
discontinue any product or service at any time without notice. TI provides customer
assistance in various technical areas, but does not have full access to data
concerning the use and applications of customer's products.
Therefore, TI assumes no liability and is not responsible for customer applications
or product or software design or performance relating to systems or applications
incorporating TI products. In addition, TI assumes no liability and is not responsible
for infringement of patents and/or any other intellectual or industrial property rights
of third parties, which may result from assistance provided by TI.
TI products are not designed, intended, authorized or warranted to be suitable for
life support applications or any other life critical applications which could involve
potential risk of death, personal injury or severe property or environmental damage.
The TI-RFID logo and the words TI-RFID and Tag-it are trade- marks or registered
trademarks of Texas Instruments Incorporated.
Copyright 2002 Texas Instruments Incorporated. All rights reserved.

February 2002 Contents
3
Table of Contents
Preface ................................................................................................................5
Chapter 1: Product Description........................................................................7
1.1 RA-RFM Module - General........................................................................8
1.2 Transmitter...............................................................................................11
1.3 Receiver...................................................................................................12
1.4 RA-RFM Connectors and Jumpers..........................................................12
1.5 Antenna Tuning Board - General.............................................................17
1.6 Antenna Tuning Board Connectors and Jumpers ...................................18
Chapter 2: Specifications................................................................................19
2.1 Recommended Operating Conditions .....................................................20
2.2 Dimensions..............................................................................................24
Chapter 3: Installation ..................................................................................... 27
3.1 Power Supply Requirements...................................................................28
3.2 Power Supply Connection .......................................................................29
Chapter 4: Associated Antenna Systems......................................................31
4.1 Antenna Requirements............................................................................32
4.2 Antenna Resonance Tuning....................................................................33
4.3 Tuning Procedure ....................................................................................34
Chapter 5: Regulatory, Safety & Warranty Notices......................................37
5.1 Regulatory Notes.....................................................................................38
5.1.1 FCC Notices (U.S.A).......................................................................38
5.1.2 CE Conformity (Europe) .................................................................38
Appendices
Appendix 1: Field Strength Adjustment .........................................................39
Appendix 2: Adjustment of Oscillator Signal Pulse Width.............................41
Appendix 3: Threshold Level Adjustment......................................................43
Appendix 4: Transmitter Carrier Phase Synchronization (CPS)....................45
Appendix 5: Noise Considerations.................................................................49
Appendix 6: Over Voltage Protection.............................................................51

High Performance RA-RFM RI-RFM-008B February 2002
4
Table Locations
Table 1: J1 Pin Functions ................................................................................................................................15
Table 2: J2 Pin Functions ................................................................................................................................15
Table 3: J4 Pin Functions ................................................................................................................................16
Table 4: Connector ANT1................................................................................................................................16
Table 5: Antenna Connection ..........................................................................................................................18
Table 6: Antenna Cable Connector..................................................................................................................18
Table 7: Tuning Capacitor Jumpers.................................................................................................................18
Table 8: J13 Earth Ground Antenna Tuning Board .........................................................................................18
Table 9: Operating Conditions .........................................................................................................................20
Table 10: Electrical Characteristics..................................................................................................................22
Table 11: Timing Characteristics .....................................................................................................................23
Table 12: Mechanical Parameters...................................................................................................................23
Table 13: Power Supply Ripple Specifications ................................................................................................28
Table 14: Antenna Requirements....................................................................................................................32
Table 15: Tuning Range Settings ....................................................................................................................35
Table 16: Oscillator Signal Pulse Width versus Resistor Value (estimated values)........................................41
Table 17: Maximum Distances between Antennas..........................................................................................46
Table 18: Characteristics of Radiated and Conducted Noise..........................................................................49
Figure Locations
Figure 1: RA-RFM System.................................................................................................................................9
Figure 2: RFM Block Schematic ......................................................................................................................10
Figure 3: Pulse Width Examples......................................................................................................................11
Figure 4: RA-RFM Top View............................................................................................................................13
Figure 5: RA-RFM Bottom View.......................................................................................................................14
Figure 6: Antenna Tuning Board Schematic....................................................................................................17
Figure 7: Mechanical Dimensions RA-RFM.....................................................................................................24
Figure 8: Mechanical Dimensions Antenna Tuning Board...............................................................................25
Figure 9: External Ground Connection (GND to GNDP) .................................................................................30
Figure 10: Antenna Tuning Pick-up Coil Configuration....................................................................................33
Figure 11: Distance between Antennas (top view)..........................................................................................46
Figure 12: Noise Testing Configuration ...........................................................................................................50
Figure 13: Circuit for Overvoltage Protection...................................................................................................52

5
Conventions
Certain conventions are used in order to display important information in this
manual, these conventions are:
WARNING:
A WARNING IS USED WHERE CARE MUST BE TAKEN, OR
A CERTAIN PROCEDURE MUST BE FOLLOWED, IN
ORDER TO PREVENT INJURY OR HARM TO YOUR
HEALTH.
CAUTION:
This indicates information on conditions which must be
met, or a procedure which must be followed, which if not
heeded could cause permanent damage to the RA-RFM.
Note:
Indicates conditions which must be met, or procedures which must be
followed, to ensure proper functioning of the RA-RFM.
Preface

7
Product Description
This chapter introduces the RA-RFM component assemblies, showing the
transmitter and receiver sections and placement of key user-accessible
components.
Topic Page
1.1 RA-RFM Module General ..........................................................................8
1.2 Transmitter...............................................................................................10
1.3 Receiver...................................................................................................11
1.4 RA-RFM Connections and Jumpers........................................................11
1.5 Tuning Module – General........................................................................16
1.6 Tuning Module Connectors and Jumpers................................................17
Chapter 1

High Performance RA-RFM RI-RFM-008B February 2002
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1.1 RA-RFM Module - General
WARNING:
CARE MUST BE TAKEN WHEN HANDLING THE RA-RFM.
HIGH VOLTAGE ACROSS THE ANTENNA TERMINALS AND
ALL ANTENNA RESONATOR PARTS CAN BE HARMFUL
TO YOUR HEALTH.
CAUTION:
This product may be subject to damage by electrostatic
discharge (ESD). It should be handled by ESD protected
personnel at ESD secured workplaces only. The
transmitter power output stage can only operate with a
limited duty cycle. Please pay attention to this whilst
performing antenna tuning procedures. Ground pins GND
and GNDP must be connected externally to avoid damage
to the unit.

February 2002 Product Description
9
The RA-RFM, together with the associated Antenna Tuning Board allows the use
of up to 120 meters of symmetrically shielded antenna cable (Twin-Ax) between an
antenna and the Reader unit. A system diagram is shown in Figure 1.
Figure 1: RA-RFM System
A
NTENNA
LOOP
A
NTENNA TUNING BOARD
TWIN-AX
CABLE
RA-RFM

High Performance RA-RFM RI-RFM-008B February 2002
10
Figure 2: RFM Block Schematic
The RA-RFM contains all the analogue functions of a TI-RFID reading unit needed
to initialize a TI-RFID transponder, delivering data and clock signals for
identification data processing.
The RA-RFM also sends the necessary programming and addressing signals to
Read/Write and Multipage transponders.
The data input and output lines, which are connected to a data processing unit, are
low-power Schottky TTL and HCMOS logic compatible.
The functions of the RA-RFM are described in the following section.
PWM
TX
Oscillator
RX
Demodulator
RXSS-
Interface RX
Amplifier
RXSS
Threshold
ATI
Int.
.
TX Power
Stage
CPS
TXCT-
RXDT
RXC
K
ATI 6
Impedance
Trans-
former
Overvoltage Protection
PWM Control Input
To
Resonance
circuit

February 2002 Product Description
11
1.2 Transmitter
The transmitter power stage is supplied with power via two separate supply lines
VSP and GNDP. Because of the high current requirements for the transmitter
power stage, these supply lines are separated from the logic section supply lines
and have two pins per line.
The ground pins for the logic section and the transmitter are not connected
internally, in order to avoid possible problems with a high resistivity of GNDP pins
and in order to increase flexibility when using long supply lines. Pins GND and
GNDP must be connected to each other externally. For more details, refer to
Chapter 3.2, Power Supply Connection.
The transmitter power stage is internally connected to the supply lines GNDP and
VSP via a common-mode choke coil in order to reduce electromagnetic
interference (EMI) on the supply lines.
The regulated transmitter power stage supply may vary between +7V and +24V.
The supply lines VSP and VSL should be connected together when the supply
voltage is +7 V or more. For details refer to Section 2, Specifications.
Note:
The RA-RFM has an in-built temperature protection circuit which
sharply limits the transmitter power stage output if an over-current
situation or an over-temperature environment causes the temperature
to exceed the allowed limits. After the device is switched off and has
time to recover (when the temperature drops again or the over-current
situation is otherwise rectified) the unit reverts to normal operation
when it is switched on again. Such an occurrence is an indication that
the RA-RFM is not being operated within specification.
The transmit frequency (134.2 kHz) from the oscillator is fed to the Pulse Width
Modulator (PWM). By changing the value of a resistor, the PWM can set the pulse
width ratio between 0% and 50%. For an example of two different oscillator signal
pulse widths see Figure 3. Decreasing the 134.2 kHz frequency pulse width ratio
decreases the generated transmit (charge-up) field strength.
It is therefore possible to adjust the generated field strength by selecting different
pulse width ratios. For more information about setting the field strength, refer to
Appendix 1, Field Strength Adjustment.
Figure 3: Pulse Width Examples
Pulse width of 50% Pulse width of 12.5%

High Performance RA-RFM RI-RFM-008B February 2002
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CAUTION:
The RA-RFM must not be operated in continuous transmit
mode when operated at full power output. When using
pulse widths smaller than 50%, the RA-RFM transmitter
power stage works in a less efficient way. This leads to an
increased power dissipation and thus to higher
temperature increase of the transmitter power stage, so
ensure that more cooling is provided.
Note:
If the RA-RFM is going to be physically located within the antenna
field, it may be necessary to shield the module by means of a metal
casing.
1.3 Receiver
The signal received from the transponder is a Frequency Shift Keying (FSK) signal
with typical low and high bit frequencies of 134.2 kHz and 123.2 kHz respectively.
The signal is received from the antenna resonator, which is capacitively coupled to
the receiver.
The signal RXCK is the reference clock signal to decode the RXDT data stream.
The RXCK signal changes from low to high level during each data bit and the
RXDT signal is valid before and after this positive slope for a certain time window.
For more details refer to Table 11, Timing Characteristics.
The receiver has a built-in RF receive signal detector. The receive signal strength
is indicated by the digital output RXSS-. This signal becomes active ( = logic LOW
level) when the received RF signal strength exceeds a defined level. This threshold
level may be adjusted with a potentiometer on the RA-RFM board and is located
near connector J1 (see Figure 5).
The RXSS- output is used for detection of other transmitting reading units and thus
can be used for wireless read cycle synchronization of several reading units.
1.4 RA-RFM Connectors and Jumpers
There are a number of connectors, jumpers and other components on the RA-RFM
available for use.
These are:
J1 Connector for supply voltages and interface signal lines to and from the
RA-RFM

February 2002 Product Description
13
J2 Connector for the (optional) Antenna Tuning Indicator (ATI), which can be
used for easy antenna tuning during installation. Main resonance tuning is
carried out with the Antenna Tuning Board near the antenna.
J4 Connector for field strength adjustment resistor and also direct access to
receiver input.
JP4 Common-mode noise choke bypass.
R409 RXSS noise level adjustment potentiometer.
SW1 Default all on (Pos. 1 CPS see Appendix 4)
A 3-pin antenna connector connects the RA-RFM via a symmetrically shielded
antenna cable (Twin-Ax) to the Antenna Tuning Board.
The RA-RFM is normally mounted from the underside utilizing appropriate spacers
and four M3 mounting bolts.
The top view of the RA-RFM (without the normally fitted heatsink) is shown in
Figure 4. Connectors J2, J4, JP4, R409, switch SW1 and the antenna terminals are
accessible from the top.
Figure 4: RA-RFM Top View
J4
J2
JP4
SW1
R409
1
2
3
A
NT1
12
3 4
12
6
1
1

High Performance RA-RFM RI-RFM-008B February 2002
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The bottom view of the RA-RFM is shown in Figure 5. The connectors J1, J2 and
J4 are accessible from the underside. J1 is the 16-pin module connector, this
carries the supply voltage lines, the data, and the control lines.
Figure 5: RA-RFM Bottom View
5
3
1
3
1
1
3
5
7
9
11
13
15
••
••
••
••
••
••
••
••
••
••
••
••
••
6
4
2
4
2
2
4
6
8
10
12
14
16
J1
J2
J4
A
NT_1
A
NT_2
GNDA
(only available
from top)

February 2002 Product Description
15
Table 1 lists the pin functions for connector J1. The connector type is 16 pin, 2 row
with 2.54 mm pin spacing.
Table 1: J1 Pin Functions
Signal Direction Description
1 GND IN Logic ground
2 TXCT- IN Transmitter control input for activation of transmitter
(active low, internal pull-up resistor)
3 VSL IN Supply voltage for logic and receiver
4 RXDT OUT Logic level compatible receiver data signal output
5 RXSA IN/OUT Receiver signal strength adjust for RXSS- threshold level
6 RXCK OUT Logic level compatible receiver clock output
7 GNDP IN Transmitter power stage ground
8 No connection
9 GNDP IN Transmitter power stage ground
10 RSTP OUT Analog receiver signal strength test pin
11 VSP IN Supply voltage for transmitter power stage
12 CPS_OUT OUT Carrier Phase Synchronization oscillator signal output
13 VSP IN Supply voltage for transmitter power stage
14 RXSS- OUT Receiver signal strength output (active low)
15 No connection
16 CPS_IN IN Carrier Phase Synchronization oscillator signal input
CAUTION:
The transmitter ground pins GNDP and logic ground pin
GND must be connected together externally. The RA-RFM
may be otherwise permanently damaged.
Table 2 lists the pin functions for the ATI connector J2: The connector type is a
6 pin, 2 row connector with 2.54 mm pin spacing.
Table 2: J2 Pin Functions
Pin# Signal Direction Description
1 TXCT-R IN Transmitter control signal via resistor (active low)
2 GND OUT Logic ground
3 VD OUT Internal regulated logic supply voltage output
4 F_OSC-R IN/OUT Pulse width modulated transmitter oscillator signal via resistor
5 RXSS- OUT Receiver signal strength output (active low)
6 F_ANT OUT Antenna resonance frequency output signal (open collector)

High Performance RA-RFM RI-RFM-008B February 2002
16
Table 3 lists the pin functions for the J4 pulse width adjustment connector. The
connector type is 4 pin, 2 row with 2.54 mm pin spacing.
Table 3: J4 Pin Functions
Pin# Signal Description
1 RX Analog transponder signal
2 GNDA Ground antenna circuit
3 Pulse width adjusting resistor connecting pin
4 GND Logic ground
Table 4 lists the functions for the antenna connector used to connect the RA-RFM
to the Antenna Tuning Board.
Table 4: Connector ANT1
Pin# Signal Direction Description
1 GNDA OUT Ground for cable shield
2 ANT_2 IN/OUT Symmetrical antenna input/output 2
3 ANT_1 IN/OUT Symmetrical antenna input/output 1
Jumper JP4 allows enabling and disabling of common noise filtering for EMI
purposes. The default setting, with common noise filtering active, jumpers pins 2
and 3. A jumper between pins 1 and 2 bypasses common noise filtering.

February 2002 Product Description
17
1.5 Antenna Tuning Board - General
In order to achieve high resonance voltage and thus high charge-up field strength,
the antenna circuit must be tuned to resonance. This is the purpose of the tuning
coil and capacitor array on this board, shown in Figure 6.
Figure 6: Antenna Tuning Board Schematic
The total resonance capacitance is as follows:
Antenna Tuning Board capacitance + cable capacitance (Antenna Tuning
Board to RA-RFM)
The main resonance capacitance consists of capacitors C1, C2, C3, C4, C5, C6,
C7 and C8 on the Antenna Tuning Board. The high resonance voltage and current
flow through the resonator necessitate connecting these capacitors both in serial
and parallel. Each resonance capacitor can be switched in and out of circuit by a
single jumper in order to tune the RFM to resonance, i.e. match the RFM to
different antenna inductances.
CAUTION:
If only one capacitor is switched parallel to the resonance
circuit, the maximum allowed resonance voltage is 280 Vp
(560 Vpp).
WARNING:
CARE MUST BE TAKEN WHEN HANDLING THE RA-RFM
SYSTEM. HIGH VOLTAGE ACROSS THE ANTENNA
TERMINALS AND ALL ANTENNA RESONATOR
COMPONENTS MAY BE HARMFUL TO YOUR HEALTH. IF
THE ANTENNA INSULATION IS DAMAGED, THE ANTENNA
SHOULD NOT BE CONNECTED TO THE RA-RFM SYSTEM.

High Performance RA-RFM RI-RFM-008B February 2002
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1.6 Antenna Tuning Board Connectors and Jumpers
A circuit diagram of the Antenna Tuning Board is shown in Figure 6. Tables 5
through 8 show connector and jumper signals. LED1, visible on the module,
indicates the presence of power.
Table 5: Antenna Connection
Pin# Signal Direction Description
1 ANT IN/OUT Symmetric antenna signal
2 Not connected
3 ANT IN/OUT Symmetric antenna signal via series L
Table 6: Antenna Cable Connector
Pin# Signal Direction Description
1 ANT IN/OUT Symmetric antenna signal from/to RFM
2 ANT IN/OUT Symmetric antenna signal from/to RFM
3 GND IN Cable shield to housing ground
Table 7: Tuning Capacitor Jumpers
Capacitance (nF) Max. Resonance Voltage
peak-peak (VRF_max) Description
JP1 33 560 Capacitor C2
JP2 16.5 800 Capacitor C1, C2 in series
JP3 33 560 Capacitor C1
JP4 33 560 Capacitor C4
JP5 16.5 800 Capacitor C3, C4 in series
JP7 15 560 Capacitor C6
JP8 7.5 800 Capacitor C5, C6 in series
JP9 15 560 CapacitorC5
JP10 10 560 Capacitor C8
JP11 5 800 Capacitor C7, C8 in series
Note:
VRF_max is the maximum allowed resonance voltage for the
respective capacitor combination.
Table 8: J13 Earth Ground Antenna Tuning Board
Pin# Signal Direction Description
1 Earth OUT Housing ground
2 GND IN Shield Twin Ax Cable
Note:
The pre-drilled mounting holes are connectable to ground.

19
Specifications
This chapter lists the recommended operating conditions, electrical and mechanical
characteristics and dimensions.
Topic Page
2.1 Recommended Operating Conditions .....................................................20
2.2 Dimensions..............................................................................................24
Chapter 2

High Performance RA-RFM RI-RFM-008B February 2002
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CAUTION:
Exceeding recommended maximum ratings may lead to
permanent damage of the RA-RFM.
The RA-RFM must not be operated in continuous transmit
mode when operated at full power output.
Install suitable heatsinks when operating the RA-RFM at
pulse widths smaller than 50%.
2.1 Recommended Operating Conditions
Table 9 shows the recommended operating conditions.
Table 9: Operating Conditions
Symbol Parameter min. typ. max. Unit
V_VSP Supply voltage of transmitter power stage 7.0 14.0 24.0 V DC
I_VSP Current consumption of transmitter power stage - refer to the
formula below 1.0 2.0 Apeak
P_VSP Peak pulse power input to transmitter power stage (I_VSP *
V_VSP * Duty Cycle) 24 W
V_ANT Antenna resonance voltage 250 380 Vpeak
V_ANT-25 Antenna resonance voltage (Pulse width setting ≤25%) 200 Vpeak
V_ANT-
ATI Minimum antenna resonance voltage for correct operation of ATI 25 Vpeak
V_VSL Supply voltage input for logic part 7.0 24.0 V DC
I_VD External current load on internal regulated logic supply voltage
output 1.0 mA
T_oper Operating free-air temperature range -25 +70 ° C
T_store Storage temperature range -40 +85 ° C
Note:
Free-air temperature is the air temperature immediately surrounding
the RA-RFM module. If the module is incorporated into a housing, it
must be guaranteed by proper design or cooling that the internal
temperature does not exceed the recommended operating conditions.