U2270B-MFPG3Y [ATMEL]
Read/Write Base Station; 读/写基站
| 型号： | U2270B-MFPG3Y |
| 厂家： | 
ATMEL |
| 描述： | Read/Write Base Station |
| 文件： | 总18页 (文件大小：308K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Features
• Carrier Frequency fosc 100 kHz to 150 kHz
• Typical Data Rate up to 5 Kbaud at 125 kHz
• Suitable for Manchester and Bi-phase Modulation
• Power Supply from the Car Battery or from 5V Regulated Voltage
• Optimized for Car Immobilizer Applications
• Tuning Capability
• Microcontroller-compatible Interface
• Low Power Consumption in Standby Mode
• Power-supply Output for Microcontroller
Read/Write
Base Station
Applications
• Car Immobilizers
• Animal Identification
• Access Control
U2270B
• Process Control
1. Description
The U2270B is an IC for IDIC® 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-spe-
cific distances. It also includes all signal-processing circuits which are necessary to
transform the small input signal into a microcontroller-compatible signal.
4684E–RFID–02/08
Figure 1-1. System Block Diagram
Read/write base station
Transponder/TAG
Carrier
enable
Osc
U2270B
RF field
typ. 125 kHz
Unlock
System
Transponder
IC
MCU
Data
NF read channel
output
Figure 1-2. Block Diagram
DVS
VEXT
VS
VBatt
Standby
Power supply
COIL1
MS
= 1
CFE
Frequency
adjustment
COIL2
DGND
&
RF
Driver
Oscillator
Output
Amplifier
HIPASS
Input
&
Lowpass filter
Schmitt trigger
GND
OE
2
U2270B
4684E–RFID–02/08
U2270B
2. Pin Configuration
Figure 2-1. Pinning
GND
OUTPUT
OE
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
HIPASS
RF
VS
INPUT
MS
STANDBY
VBATT
DVS
CFE
DGND
COIL2
VEXT
COIL1
Table 2-1.
Pin Description
Symbol
GND
Pin
1
Function
Ground
2
OUTPUT
OE
Data output
Data output enable
Data input
3
4
INPUT
MS
5
Mode select coil 1: common mode/differential mode
Carrier frequency enable
Driver ground
6
CFE
7
DGND
COIL2
COIL1
VEXT
8
Coil driver 2
9
Coil driver 1
10
11
12
13
14
15
16
External power supply
Driver supply voltage
Battery voltage
DVS
VBatt
STANDBY
VS
Standby input
Internal power supply (5V)
Frequency adjustment
DC decoupling
RF
HIPASS
3
4684E–RFID–02/08
3. Functional Description
3.1
Power Supply (PS)
Figure 3-1. Equivalent Circuit of Power Supply and Antenna Driver
DVS VEXT
VS VBatt
Standby
Internal supply
9V
25 kΩ
12 kΩ
6V
6V
18V
PS
COILx
DRV
DGND
The U2270B can be operated with one external supply voltage or with two externally-stabilized
supply voltages for an extended driver output voltage or from the 12V battery voltage of a vehi-
cle. The 12V supply capability is achieved via the on-chip power supply (see Figure 3-1). The
power supply provides two different output voltages, VS and VEXT
.
VS is the internal power supply voltage for everything except for the driver circuit. Pin VS is used
to connect a block capacitor. VS can be switched off by the STANDBY pin. In standby mode, the
chip’s power consumption is very low. VEXT is the supply voltage of the antenna’s pre-driver.
This voltage can also be used to operate external circuits, such as a microcontroller. In conjunc-
tion with an external NPN transistor, it also establishes the supply voltage of the antenna coil
driver, DVS.
4
U2270B
4684E–RFID–02/08
U2270B
3.2
Operation Modes to Power the U2270B
The following section explains the three different operation modes to power the U2270B.
3.2.1
One-rail Operation
All internal circuits are operated from one 5V power rail (see Figure 3-2). In this case, VS, VEXT
and DVS serve as inputs. VBatt is not used but should also be connected to that supply rail.
Figure 3-2. One-rail Operation Supply
+5V (stabilized)
+
DVS VEXT
VS VBatt Standby
3.2.2
Two-rail Operation
In this application, the driver voltage, DVS, and the pre-driver supply, VEXT, 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 (see Figure 3-3). VS is connected to a 5V supply, whereas the driver volt-
ages can be as high as 8V. This operation mode is intended to be used in situations where an
extended communication distance is required.
Figure 3-3. Two-rail Operation Supply
7V to 8V (stabilized)
+
5V (stabilized)
+
DVS VEXT
VS VBatt Standby
3.2.3
Battery-voltage Operation
Using this operation mode, VS and VEXT are generated by the internal power supply (see Figure
3-4 on page 6). For this mode, an external voltage regulator is not needed. The IC can be
switched off via the STANDBY pin. VEXT supplies the base of an external NPN transistor and
external circuits, like a microcontroller (even in standby mode).
Pin VEXT and VBatt are overvoltage protected via internal Zener diodes (see Figure 3-1 on page
4).The maximum current into the pins is determined by the maximum power dissipation and the
maximum junction temperature of the IC.
5
4684E–RFID–02/08
Figure 3-4. Battery Operation
7V to 16V
DVS VEXT
VS VBatt Standby
Table 3-1.
Characteristics of the Various Operation Modes
Driver Output
Voltage Swing
Standby Mode
Available
Operation Mode
External Components Required
Supply-voltage Range
1 voltage regulator
1 capacitor
One-rail operation
5V ±10%
≈ 4V
No
No
2 voltage regulators
2 capacitors
5V ±10%
7V to 8V
Two-rail operation
6V to 7V
1 transistor
2 capacitors
Battery-voltage operation
Optional, for load dump protection:
1 resistor
6V to 16V
≈ 4V
Yes
1 capacitor
3.3
Oscillator (Osc)
The frequency of the on-chip oscillator is controlled by a current fed into the RF input. An inte-
grated compensation circuit ensures a wide temperature range and a supply-voltage–
independent frequency which is selected by a fixed resistor between RF (pin 15) and VS (pin 14).
For 125 kHz, a resistor value of 110 kΩ is defined. For other frequencies, use the following
formula:
14375
R [kΩ]= --------------------- – 5
t
f [kHz]
0
This input can be used to adjust the frequency close to the resonance of the antenna. For more
details see Section “Applications” on page 10.
Figure 3-5. Equivalent Circuit of Pin RF
VS
Rf
2 kΩ
RF
6
U2270B
4684E–RFID–02/08
U2270B
3.4
Low-pass Filter (LPF)
The fully integrated low-pass filter (4th-order Butterworth) removes the remaining carrier signal
and high-frequency disturbances after demodulation. The upper cut-off frequency of the LPF
depends on the selected oscillator frequency. The typical value is fOsc / 18, and 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 Fig-
ure 3-6. The input voltage swing is limited to 2 Vpp. For frequency response calculation, the
impedances of the signal source and LPF input (typical 210 kΩ) have to be considered. The rec-
ommended values of the input capacitor for selected data rates are given in Section 4.,
“Applications” , on page 10.
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.
Figure 3-6. Equivalent Circuit of Pin Input
VBias + 0.4V
RS
Input
10 kΩ
CIN
210 kΩ
V
Bias - 0.4V
3.5
Amplifier (AMP)
The differential amplifier has a fixed gain, typically 30. The HIPASS pin is used for DC decou-
pling. The lower cut-off frequency of the decoupling circuit can be calculated as follows:
1
fcut = --------------------------------------------
2 × π × CHP × Ri
The value of the internal resistor Ri can be assumed to be 2.5 kΩ.
Recommended values of CHP for selected data rates can be found in Section 4., “Applications” ,
on page 10.
7
4684E–RFID–02/08
Figure 3-7. Equivalent Circuit of Pin HIPASS
R
+
-
Schmitt
trigger
R
LPF
VRef
R
R
Ri
HIPASS
CHP
3.6
Schmitt Trigger
The signal is processed by a Schmitt trigger to suppress possible noise and to make the signal
microcontroller-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).
Figure 3-8. Equivalent Circuit of Pin OE
7 µA
OE
8
U2270B
4684E–RFID–02/08
U2270B
3.7
Driver (DRV)
The driver supplies the antenna coil with the appropriate energy. The circuit consists of two inde-
pendent 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 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 various functions are controlled
by the inputs MS and CFE (see “Function Table” on page 10). The equivalent circuit of the driver
is shown in Figure 3-1 on page 4.
Figure 3-9. Equivalent Circuit of Pin MS
30 µA
MS
Figure 3-10. Equivalent Circuit of Pin CFE
30 µA
CFE
9
4684E–RFID–02/08
3.8
Function Table
CFE
Low
Low
MS
Low
High
COIL1
High
COIL2
High
Low
High
High
High
Low
High
OE
Low
High
Output
Enabled
Disabled
STANDBY
Low
U2270B
Standby mode
Active
High
4. Applications
To achieve the system performance, consider the power-supply environment and the mag-
netic-coupling situation.
The selection of the appropriate power-supply operation mode depends on the quality of supply
voltage. If an unregulated supply voltage in the range of V = 7V to 16V is available, the internal
power supply of the U2270B can be used. In this case, standby mode can be used and an exter-
nal low-current microcontroller can be supplied.
If a 5V supply rail is available, it can be used to power the U2270B. In this case, check that the
voltage is noise-free. An external power transistor is not necessary.
The application also depends on the magnetic-coupling situation. The coupling factor mainly
depends on the transmission distance and the antenna coils. The following table lists the appro-
priate application for a given coupling factor. The magnetic coupling factor can be determined
using Atmel®’s test transponder coil.
Table 4-1.
Magnetic Coupling
Magnetic Coupling Factor
k > 3%
Appropriate Application
Free-running oscillator
Diode feedback
k > 1%
Diode feedback
plus frequency altering
k > 0.5%
k > 0.3%
Diode feedback
plus fine frequency tuning
The maximum transmission distance is also influenced by the accuracy of the antenna’s reso-
nance. 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 fres = 125 kHz ± 3%. Further
details concerning the adequate application and the antenna design is provided in Section
“Antenna Design Hints”.
10
U2270B
4684E–RFID–02/08
U2270B
The application of the U2270B includes the two capacitors CIN and CHP whose values are lin-
early dependent 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.
Table 4-2.
Data Rate f = 125 kHz
f / 32 = 3.9 Kbits/s
f / 64 = 1.95 Kbits/s
Recommended Capacitor Values
Input Capacitor (CIN)
Decoupling Capacitor (CHP
)
680 pF
1.2 nF
100 nF
220 nF
The following applications are typical examples. The values of CIN and CHP correspond to the
transponder’s data rate only. The arrangement to fit the magnetic-coupling situation is also inde-
pendent of other design issues except for 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 d ≈ 10 cm.
4.1
Application 1
Application using few external components. This application is for intense magnetic coupling
only.
Figure 4-1. Application Circuit 1
110 kΩ
5V
VEXT VS
VDD
VBatt
DVS
+
47 nF
47 µF
RF
U2270B
MS
CFE
OE
INPUT
Micro-
controller
CIN
STANDBY
OUTPUT
HIPASS
1N4148
R
1.35 mH
CHP
470 kΩ
COIL1
COIL2
1.5 nF
VSS
1.2 nF
DGND GND
11
4684E–RFID–02/08
4.2
Application 2
Basic application using diode feedback. This application allows higher communication distances
than .“Application 1”
Figure 4-2. Application Circuit 2
BC639
360Ω
+
12V
4 ×
1N4148
68 kΩ
22 µF
+
+
GND
4.7 nF
22 µF
75 kΩ
22 µF
100 kΩ
43 kΩ
VS VEXT DVS VBatt
VDD
RF
MS
1.2 nF
COIL2
CFE
U2270B
82Ω
1.35 mH
Antenna
Micro-
controller
COIL1
Input
Standby
Output
OE
I/O
CIN
CHP
1N4148
HIPASS
1.5 nF
VSS
470 kΩ
DGND GND
12
U2270B
4684E–RFID–02/08
U2270B
4.3
Application 3
This application is comparable to “Application 2” but alters the operating frequency. This allows
higher antenna resonance tolerances and/or higher communication distances. This application
is preferred if the detecting microcontroller is close to the U2270B, as an additional microcontrol-
ler signal controls the adequate operating frequency.
Figure 4-3. Application Circuit 3
4 ×
1N4148
68 kΩ
+
5V
4.7 nF
22 µF
47 nF
75 kΩ
100 kΩ
43 kΩ
GND
VS VEXT DVS VBatt
VDD
RF
MS
1 nF
COIL2
CFE
U2270B
82Ω
1.5 mH
Micro-
controller
COIL1
Input
Standby
Output
OE
Antenna
CIN
1N4148
180 pF
100Ω
HIPASS
VSS
470 kΩ
DGND GND
1.5 nF
4.7 kΩ
CHP
BC846
1.5 kΩ
Note:
Application examples have not been examined for series production or reliability, and no worst
case scenarios have been developed. Customers who adapt any of these proposals must carry
out their own testing and be convinced that no negative consequences arise from the proposals.
13
4684E–RFID–02/08
5. Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
All voltages are referred to GND (Pins 1 and 7)
Parameter
Pin
Symbol
Min.
Max.
Unit
Operating voltage
12
VBatt
VS
16
V
VS, VEXT, DVS, Coil
1, Coil 2
Operating voltage
8, 9, 10, 11, 14
–0.3
8
V
V
Range of input and output
voltages
3, 4, 5, 6, 15, 16
2 and 13
VIN
VOUT
–0.3
–0.3
VS + 0.3
VBatt
Output current
10
2
IEXT
IOUT
ICoil
Ptot
Tj
10
mA
mA
mA
mW
°C
Output current
10
Driver output current
Power dissipation SO16
Junction temperature
Storage temperature
Ambient temperature
8 and 9
200
380
150
125
105
Tstg
Tamb
–55
–40
°C
°C
6. Thermal Resistance
Parameter
Symbol
Value
Unit
Thermal resistance SO16
RthJA
120
K/W
7. Operating Range
All voltages are referred to GND (Pins 1 and 7)
Parameter
Pin
12
Symbol
VBatt
Value
7 to 16
Unit
V
Operating voltage
Operating voltage
Operating voltage
Carrier frequency
14
VS
4.5 to 6.3
4.5 to 8
V
10, 11
VEXT, DVS
V
100 to 150
kHz
14
U2270B
4684E–RFID–02/08
U2270B
8. Electrical Characteristics
All voltages are referred to GND (Pins 1 and 7)
Parameters
Test Conditions
Pin
Symbol
Min.
Typ.
Max.
Unit
Data output
- Collector emitter
- Saturation voltage
Iout = 5 mA
2
VCEsat
400
0.5
mV
Data output enable
- Low-level input voltage
- High-level input voltage
3
4
Vil
Vih
V
V
2.4
Data input
- Clamping level low
- Clamping level high
- Input resistance
- Input sensitivity
Vil
Vih
Rin
SIN
2
3.8
220
V
V
kΩ
f = 3 kHz (square wave)
Gain capacitor = 100 nF
10
2.4
3.0
mVpp
Driver polarity mode
- Low-level input voltage
- High-level input voltage
5
6
Vil
Vih
V
V
0.2
Carrier frequency enable
- Low-level input voltage
- High-level input voltage
Vil
Vih
V
V
0.8
9
10,
11,12
and
5V application without load
connected to the coil driver
Operating current
IS
4.5
30
mA
µA
14
Standby current
12V application
12
ISt
70
VS
- Supply voltage
- Supply voltage drift
- Output current
VS
dVs/dT
IS
4.6
1.8
5.4
4.2
3.5
6.3
V
mV/K
mA
14
Driver output voltage
- One-rail operation
- Battery-voltage operation
IL = ±100 mA
VS, VEXT, VBatt, DVS = 5V
VBatt = 12V
8, 9
10
VDRV
VDRV
2.9
3.1
3.6
4.0
4.3
4.7
VPP
VPP
VEXT
- Output voltage
- Supply voltage drift
- Output current
- Standby output current
VEXT
dVEXT/dT
IEXT
4.6
5.4
4.2
6.3
V
mV/K
mA
IC active
Standby mode
3.5
0.4
IEXT
mA
Standby input
- Low-level input voltage
- High-level input voltage
13
Vil
Vih
0.8
V
V
3.1
Oscillator
- Carrier frequency
RF resistor = 110 kΩ
f0
121
125
129
kHz
kHz
(“Application 2” ), REM 1(1)
Low-pass filter
- Cut-off frequency
Carrier frequency = 125 kHz
fcut
7
Amplifier gain
CHP = 100 nF
30
Note:
1. REM 1: In “Application 1” where the oscillator operates in free-running mode, the IC must be soldered free from distortion.
Otherwise, the oscillator may be out of bounds.
15
4684E–RFID–02/08
9. Ordering Information
Extended Type Number
Package
SO16
Remarks
U2270B-MFPY
Tube, Pb-free
U2270B-MFPG3Y
SO16
Taped and reeled, Pb-free
10. Package Information
Package: SO 16
Dimensions in mm
9.9±0.1
5±0.2
3.7±0.1
3.8±0.1
6±0.2
0.4
1.27
8.89
16
9
technical drawings
according to DIN
specifications
1
8
Drawing-No.: 6.541-5031.02-4
Issue: 1; 15.08.06
Pin 1 identity
16
U2270B
4684E–RFID–02/08
U2270B
11. Revision History
Please note that the following page numbers referred to in this section refer to the specific revision
mentioned, not to this document.
Revision No.
History
• Put datasheet in a new template
• Section 3.4 “Low-pass Filter (LPF) on page 7: Typo removed
4684E-RFID-01/08
• Section 8 “Electrical Characteristics” on page 15: Parameter VS alignment
corrected
• Put datasheet in a new template
• Pb-free logo on page 1 deleted
4684D-RFID-09/06
4684C-RFID-12/05
4684B-RFID-09/05
• Section 10 “Package Information” on page 16 changed
• Minor grammatical corrections and fixed broken cross references
• Last page: Legal sentence changed
• Put datasheet in a new template
• Pb-free Logo on page 1 added
• New heading rows on Table “Absolute Maximum Ratings” on page 14 added
• Ordering Information on page 16 changed
17
4684E–RFID–02/08
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4684E–RFID–02/08
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