U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
1 (13)
Read / Write Base Station IC
Description
IC for IDIC *) read-write base stations
The U2270B is a bipolar integrated circuit for read-write
base stations in contactless identification and immobilizer systems.
The IC incorporates the energy transfer circuit to supply
the transponder. It consists of an on-chip power supply, an
oscillator, and a coil driver optimized for automotive-
specific distances. It also includes all signal-processing
circuits which are necessary to form the small input signal
into a microcontroller-compatible signal.
The U2270B is well suitable to perform read operations
with e5530-GT and TK5530-PP transponders and also
performs read-write operations with TK5550-PP and
TK5560-PP transponders.
Features
D
Carrier frequency f
osc
100 KHz – 150 KHz
D
Typical data rate up to 5 Kbaud at 125 KHz
D
Suitable for Manchester and Bi-phase modulation
D
Power supply from the car battery or from
5-V regulated voltage
D
Optimized for car immobilizer applications
D
Tuning capability
D
Microcontroller-compatible interface
D
Low power consumption in standby mode
D
Power supply output for microcontroller
Applications
D
Car immobilizers
D
Animal identification
D
Access control
D
Process control
D
Further industrial applications
Case: SO16 U2270B-FP
enable
Read / write base station
MCU
Unlock
Syste
m
RF– Field
typ. 125 kHz
Transp.
IC
e5530
e5550
e5560
Transponder / TAG
9300
Carrier
output
Data
NF read channel
Osc
U2270B
TK5530-PP
e5530-GT
TK5550-PP
TK5560-PP
Figure 1.
*)
IDIC stands for IDentification Integrated Circuit and is a trademark of TEMIC.
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
2 (13)
Pin Description
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
OE
Output
GND
CFE
MS
Input
COIL2
DGND
V
S
RF
HIPASS
DV
S
V
Batt
Standby
COIL1
V
EXT
9844
Figure 2. Pinning
Pin Symbol Function
1 GND Ground
2 Output Data output
3 OE Data output enable
4 Input Data input
5 MS Mode select coil 1: Common
mode / Differential mode
6 CFE Carrier frequency enable
7 DGND Driver ground
8 COIL 2 Coil driver 2
9 COIL 1 Coil driver 1
10 V
EXT
External power supply
11 DV
S
Driver supply voltage
12 V
Batt
Battery voltage
13 Standby Standby input
14 V
S
Internal power supply (5 V)
15 RF Frequency adjustment
16 HIPASS DC decoupling
Block Diagram
Frequency
adjustment
&
&
Power supply
Driver
Low pass filter
Amplifier
= 1
Oscillator
Schmitt trigger
V
EXT
DV
S
V
S
V
Batt
COIL1
COIL2
DGND
Input
HIPASS OEGND
Standby
MS
CFE
RF
Output
9692
Figure 3.
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
3 (13)
Functional Description
Power Supply (PS)
V
Batt
6 V 6 V 18 V
25 k
W
12 k
W
internal supply
V
S
9 V
PS
DRV
DV
S
Standby
COILx
DGND
11413
V
EXT
Figure 4. Equivalent circuit of power supply and antenna driver
The U2270 can be operated with one external supply
voltage or with two externally-stabilized supply voltages
for an extended driver output voltage or from the 12-V
battery voltage of a vehicle. The 12-V supply capability
is achieved via the on-chip power supply (see figure 4).
The power supply provides two different output voltages,
V
S
and V
EXT
.
V
S
is the internal power supply voltage except for the
driver circuit. Pin V
S
is used to connect a block capacitor.
V
S
can be switched off by the pin STANDBY. In standby
mode, the chip’s power consumption is very low. V
EXT
is
the supply voltage of the antenna’s pre-driver. This
voltage can also be used to operate external circuits, i.e.,
a microcontroller. In conjunction with an external NPN
transistor, it also establishes the supply voltage of the
antenna coil driver, DVS.
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
4 (13)
The following section explains the 3 different
operation modes to power the U2270B.
1. One-rail operation
All internal circuits are operated from one 5-V power rail.
(see figure 5). In this case, V
S
,V
EXT
and DVS serve as
inputs. V
Batt
is not used but should also be connected to
that supply rail.
DVSV
EXTVSVBatt
Standby
+5 V (stabilized)
12579
Figure 5.
2. Two-rail operation
In that application, the driver voltage, DV
S,
and the
pre-driver supply, V
EXT
, are operated at a higher voltage
than the rest of the circuitry to obtain a higher
driver-output swing and thus a higher magnetic field,
refer to figure 6. V
S
is connected to a 5-V supply, whereas
the driver voltages can be as high as 8 V. This operation
mode is intended to be used in situations where an
extended communication distance is required.
DVSV
EXTVSVBatt
Standby
5 V (stabilized)
12580
7 to 8 V (stabilized)
Figure 6.
3. Battery-voltage operation
Using this operation mode, V
S
and V
EXT
are generated by
the internal power supply. (refer to figure 7). For this
mode, an external voltage regulator is not needed. The IC
can be switched off via the pin Standby . V
EXT
supplies the
base of an external NPN transistor and external circuits,
i.e., a microcontroller (even in Standby mode).
Pin V
EXT
and V
Batt
are overvoltage protected via internal
Zener diodes (refer figure 4).The maximum current into
that pins is determined by the maximum power dissipation and the maximum junction temperature of the IC. For
a short-time current pulse, a higher power dissipation can
be assumed (refer to application note ANT019).
DVSV
EXTVSVBatt
Standby
12600
7 to 16 V
Figure 7.
Table 1. The following table summarizes the characteristics of the various operation modes.
Operation Mode External Components Re-
quired
Supply Voltage Range Driver Output
Voltage Swing
Standby Mode
A vailable
ББББББ
Á
1. One-rail operation
БББББББ
Á
1 Voltage regulator
1 Capacitor
БББББББ
Á
5 V ± 10%
БББББ
Á
[
4 V
ÁÁÁÁ
Á
No
ББББББ
Á
2. Two-rail operation
БББББББ
Á
2 Voltage regulators
2 Capacitors
БББББББ
Á
5 V ± 10%
7 V to 8 V
БББББ
Á
6 V to 7 V
ÁÁÁÁ
Á
No
ББББББ
Á
ББББББ
Á
ББББББ
Á
3. Battery voltage
operation
БББББББ
Á
БББББББ
Á
БББББББ
Á
1 Transistor
2 Capacitors
Optional for load-dump
protection:
1 Resistor
1 Capacitor
БББББББ
Á
БББББББ
Á
БББББББ
Á
6 V to 16 V
БББББ
Á
БББББ
Á
БББББ
Á
[
4 V
ÁÁÁÁ
Á
ÁÁÁÁ
Á
ÁÁÁÁ
Á
Yes
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
5 (13)
Oscillator (Osc)
The frequency of the on-chip oscillator is controlled by a
current fed into the R
F
input. An integrated compensation
circuit ensures a widly temperature and supply voltage independent frequency which is selected by a fixed resistor
between R
F
(pin 15) and VS (pin 14). For 125 kHz a resistor value of 110 kW is defined. For other frequencies, use
the following formula:
R
f
+
14375
f
0
[kHz]
–5k
W
This input can be used to adjust the frequency close to the
resonance of the antenna. For more details refer to the applicatons and the application note ANT019.
V
CC
R
F
2 k
W
9695
R
f
Figure 8. Equivalent circuit of Pin R
F
Filter (LPF)
The fully-integrated low-pass filter (4th order butterworth) removes the remaining carrier signal and
high-frequency disturbancies after demodulation. The
upper cut-off frequency of the LPF depends on the selected oscillator frequency . The typ. value is fosc/18. That
means that data rates up to fosc/25 are possible if Bi-phase
or Manchester encoding is used.
A high-pass characteristic results from the capacitive
coupling at the input Pin 4, as shown in figure 9. The input
voltage swing is limited to 2 V
pp
. For frequency response
calculation, the impedances of the signal source and LPF
input (typ. 220 kW) have to be considered. The recommended values of the input capacitor for selected data
rates are shown in the chapter “Applications”.
Note: After switching on the carrier, the dc voltage of
the coupling capacitor changes rapidly. When
the antenna voltage is stable, the LPF needs
approximately 2 ms to recover full sensitivity.
10 k
W
210 k
W
V
Bias
– 0.4 V
C
IN
R
S
~
~
12601
V
Bias
+ 0.4 V
V
Bias
Figure 9. Equivalent circuit of Pin Input
Amplifier (AMP)
The differential amplifier has a fixed gain, typically 30.
The HIPASS pin is used for dc decoupling. The lower
cut–off frequency of the decoupling circuit can be
calculated as follows:
f
cut
+
1
2 p C
HP
R
i
The value of the internal resistor Ri can be assumed to be
2.5 kW.
Recommended values of C
HP
for selected data rates can
be found in the chapter “Applications”.
+
–
V
Ref
R
R
R R
R
i
Schmitt
trigger
LPF
HIPASS
C
HP
12578
Figure 10. Equivalent circuit of pin HIPASS
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
6 (13)
Schmitt Trigger
The signal is processed by a Schmitt trigger to suppress
possible noise and to make the signal mC compatible. The
hysteresis level is 100 mV symmetrically to the dc operation point. The open-collector output is enabled by a low
level at OE
(Pin 3).
12602
7 mA
OE
Figure 11. Equivalent circuit of Pin OE
Driver (DRV)
The driver supplies the antenna coil with the appropriate
energy. The circuit consists of two independant output
stages. These output stages can be operated in two
different modes. In common mode, the outputs of the
stages are in phase. In this mode, the outputs can be
interconnected, to achieve a high current output
capability. Using the differential mode, the output
voltages are in anti-phase. Thus, the antenna coil is driven
with a higher voltage. For a specific magnetic field, the
antenna coil impedance is higher for the differential
mode. As a higher coil impedance results in a better
system sensitivity, the differential mode should be
preferred.
The CFE input is intended to be used for writing data into
a read/write or a crypto transponder. This is achieved by
interrupting the RF field with short gaps. The TEMIC
write method is described in the data sheets of TK5550
and TK5560. The various functions are controlled by the
inputs MS and CFE, refer to function table. The
equivalent circuit of the driver is shown in figure 4.
12603
30 mA
MS
Figure 12. Equivalent circuit of Pin MS
12604
30 mA
CFE
Figure 13. Equivalent circuit of Pin CFE
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
7 (13)
Function Table
CFE MS COIL1 COIL2
Low
Low
High
High
Low
High
Low
High
БББББББ
Á
БББББББ
Á
High
БББББББ
БББББББ
Low
БББББББ
Á
БББББББ
Á
High
БББББББ
БББББББ
High
OE Output
Low
Enabled
High
Disabled
Standby U2270B
Low
Standby mode
High
Active
Applications
To achieve the suitable application, consider the power
supply environment and the magnetic coupling situation.
The selection of the appropriate power supply operation
mode depends on the supply environment. If an
unregulated supply voltage in the range of V = 7 V to 16 V
is available, the internal power supply of the U2270B can
be used. In this case, the standby mode can be used and
an external low-current µC can be supplied.
If a 5-V supply rail is available, it can be used to power
the U2270B. In this case please check that the voltage is
noise-free. An external power transistor is not necessary .
The application depends also on the magnetic coupling
situation. The coupling factor mainly depends on the
transmission distance and the antenna coils. The
following table lists the appropriate application for a
given coupling factor. The magnetic coupling factor can
be determined using the TEMIC test transponder coil.
Magnetic Coupling
Factor
Appropriate Application
k > 3%
Free-running oscillator
k > 1%
Diode feedback
ББББББ
Á
k > 0.5%
БББББББ
Á
Diode feedback
plus frequency altering
ББББББ
Á
k > 0.3%
БББББББ
Á
Diode feedback
plus fine frequency tuning
The maximum transmission distance is also influenced by
the accuracy of the antenna’s resonance. Therefore, the
recommendations given above are proposals only . A good
compromise for the resonance accuracy of the antenna is
a value in the range of f
res
= 125 kHz ± 3%. Further details
concerning the adequate application and the antenna
design is provided in the TEMIC application note
ANT019 and in the TEMIC article “Antenna Design
Hints”.
The application of the U2270B includes the two
capacitors C
IN
and CHP whose values are linearly
dependend on the transponder’s data rate. The following
table gives the appropriate values for the most common
data rates. The values are valid for Manchester and
Bi-phase code.
Data Rate
f = 125 kHz
Input Capacitor
(C
IN
)
Decoupling
Capacitor (C
HP
)
f/32 = 3.9 kbit/s
680 pF
100 nF
f/64 = 1.95 kbit/s
1.2 nF
220 nF
The following applications are typical examples. The
values of C
IN
and CHP correspond to the transponder’s
data rate only. The arrangement to fit the magnetic
coupling situation is also independent from other design
issues exept of one constellation. This constellation,
consisting of diode feedback plus fine frequency tuning
together with the two-rail power supply should be used
if the transmission distance is in the range of d [ 10 cm.
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
8 (13)
Application 1
Application using few external components. This application is for intense magnetic coupling only .
RF
MS
CFE
OE
STANDBY
OUTPUT
HIPASS
INPUT
COIL1
COIL2
110 k
W
1.35 mH
R
1.2 nF
1N4148
1.5 nF
470 k
W
47 mF
5 V
DGND GND
U2270B
Micro-
controller
9693
47 nF
DV
S
V
Batt
V
EXTVS
C
IN
C
HP
V
DD
V
SS
Figure 14.
Application 2
Basic application using diode feedback. This application permits higher communication distances than application 1.
82
W
22 mF
1.35 mH
1.2 nF
4x
1N4148
100 k
W
75 k
W
Antenna
1N4148
4.7 nF
43 k
W
68 k
W
V
S
RF
V
EXT
DVSV
Batt
COIL 2
COIL 1
Input
HIPASS
DGND GND
C
HP
MS
CFE
Standby
Output
OE
U2270B
Micro-
controller
22 mF
22 mF
360
W
V
DD
I / O
12 V
GND
470 k
W
1.5 nF
C
IN
V
SS
12605
BC639
Figure 15.
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
9 (13)
Application 3
This application is comparable to application 2 but alters
the operating frequency. This permits higher antenna
resonance tolerances and/or higher communication
distances. This application is preferred if the detecting
µC is close to the U2270B as an additional µC signal
controls the adequate operating frequency .
82
W
1.5 mH
1 nF
4x 1N4148
100 k
W
75 k
W
Antenna
1N4148
4.7 nF
43 k
W
68 k
W
V
S
RF
V
EXTDVSVBatt
COIL 2
COIL 1
Input
HIPASS
DGND GND
C
HP
MS
CFE
Standby
Output
OE
U2270B
Micro-
controller
22 mF
V
DD
5 V
GND
470 k
W
1.5 nF
C
IN
V
SS
12606
180 pF
100
W
4.7 k
W
BC846
1.5 k
W
47 nF
Figure 16.
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
10 (13)
Absolute Maximum Ratings
All voltages are referred to GND (Pins 1 and 7).
Parameters/Conditions Pin Symbol Min. T yp. Max. Unit
Operating voltage Pin 12 V
Batt
V
S
16 V
Operating voltage Pins 8, 9, 10, 11 and 14 VS, V
EXT
,
DV
S
, Coil 1,
Coil 2
–0.3 8 V
Range of input and output voltages
Pins 3, 4, 5, 6, 15 and 16
Pins 2 and 13
–0.3
–0.3
VS+0.3
V
Batt
V
Output current Pin 10 I
EXT
10 mA
Output current Pin 2 I
OUT
10 mA
Driver output current Pins 8 and 9 I
Coil
200 mA
Power dissipation SO16 P
tot
380 mW
Junction temperature T
j
150 °C
Storage temperature T
stg
–55 125 °C
Ambient temperature T
amb
–40 105 °C
Thermal Resistance
Parameters/Conditions Pin Symbol Min. Typ. Max. Unit
Thermal resistance SO16 R
thJA
120 K/W
Operating Range
All voltages are referred to GND (Pins 1 and 7)
Parameters/Conditions Pin Symbol Min. T yp. Max. Unit
Operating voltage Pin 12 V
Batt
7 12 16 V
Operating voltage Pin 14 V
S
4.5 5.4 6.3 V
Operating voltage Pin 10
Pin 11
V
EXT
DV
S
4.5 8
Carrier frequency f
osc
100 125 150 kHz
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
11 (13)
Electrical Characteristics
Test conditions (unless otherwise specified): V
Batt
= 12 V, T
amb
= –40 to 105_C
Parameters Test Conditions / Pins Symbol Min. Typ. Max. Unit
Data output
– collector emitter
saturation voltage
Pin 2
I
out
= 5 mA V
CEsat
400 mV
Data output enable
– low level input voltage
– high level input voltage
Pin 3
V
il
V
ih
2.4
0.5 V
V
Data input
– clamping level low
– clamping level high
– input resistance
– input sensitivity
Pin 4
f = 3 kHz (squarewave)
gain capacitor = 100 nF
V
il
V
ih
R
in
10
2
3.8
220
V
V
k
W
mV
pp
Driver polarity mode
– low level input voltage
– high level input voltage
Pin 5
V
il
V
ih
2.4
0.2 V
V
Carrier frequency enable
– low level input voltage
– high level input voltage
Pin 6
V
il
V
ih
3.0
0.8 V
V
Operating current Pin10, 11, 12 and 14
5 V application without
load connected to the coil
driver
I
S
4.5 9 mA
Standby current Pin 12
12 V application
I
St
30 70
m
A
V
S
– Supply voltage
– Supply voltage drift
– Output current
Pin 14
V
S
dVs/dT
I
S
4.6
1.8
5.4
4.2
3.5
6.3 V
mV/K
mA
Driver output voltage
– One rail operation
– Battery voltage operation
IL = ±100 mA
V
S
, V
EXT
, V
Batt
, DVS = 5 V
V
Batt
= 12 V Pins 8 and 9
V
DRV
V
DRV
2.9
3.1
3.6
4.0
4.3
4.7
V
PP
V
PP
Vext
– Output voltage
– Supply voltage drift
– Output current
– Standby output current
Pin 10
IC active
standby mode
V
EXT
dV
EXT
/dT
I
EXT
I
EXT
4.6
3.5
0.4
5.4
4.2
6.3 V
mV/K
mA
mA
Standby input
– low level input voltage
– high level input voltage
Pin 13
V
il
V
ih
3.1
0.8 V
V
Oscillator
– Carrier frequency
RF-resistor = 110 k
W
(application 2), REM 1.
f
0
121 125 129 kHz
Low pass filter
– Cut off frequency
Carrier freq. = 125 kHz f
cut
7 kHz
Amplifier
– Gain
CHP = 100 nF 30
Schmitt trigger
– Hysteresis voltage
100 mV
REM 1.: In application 1. where the oscillator operates in the free running mode, the IC must be soldered free from distortion. Otherwise,
the oscillator frequency may be out of bounds.
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
12 (13)
Dimensions in mm
Package: SO16
94 8875
U2270B
TELEFUNKEN Semiconductors
Rev . A3, 13-Dec-96
13 (13)
Ozone Depleting Substances Policy Statement
It is the policy of TEMIC TELEFUNKEN microelectronic GmbH to
1. Meet all present and future national and international statutory requirements.
2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems
with respect to their impact on the health and safety of our employees and the public, as well as their impact on
the environment.
It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as
ozone depleting substances (ODSs).
The Montreal Protocol ( 1987) and its London Amendments (1990) intend to severely restrict the use of ODSs and
forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban
on these substances.
TEMIC TELEFUNKEN microelectronic GmbH semiconductor division has been able to use its policy of
continuous improvements to eliminate the use of ODSs listed in the following documents.
1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively
2. Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental
Protection Agency (EPA) in the USA
3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C (transitional substances) respectively.
TEMIC can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain
such substances.
We reserve the right to make changes to improve technical design and may do so without further notice.
Parameters can vary in different applications. All operating parameters must be validated for each customer
application by the customer. Should the buyer use TEMIC products for any unintended or unauthorized
application, the buyer shall indemnify TEMIC against all claims, costs, damages, and expenses, arising out of,
directly or indirectly, any claim of personal damage, injury or death associated with such unintended or
unauthorized use.
TEMIC TELEFUNKEN microelectronic GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany
Telephone: 49 (0)7131 67 2831, Fax number: 49 (0)7131 67 2423
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