U2270B_08 ATMEL | Alldatasheet
Document overview
- Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 18
Technical content
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
Applications
Car Immobilizers Animal Identification Access Control 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. Read/Write Base Station U2270B 4684E–RFID–02/08
4684E–RFID–02/08 U2270B 2. Pin Configuration Figure 2-1. Pinning VEXT COIL1 DVS VBATT HIPASS VS RF STANDBY DGND COIL2 CFE MS GND 16 OE OUTPUT INPUT Table 2-1. Pin Description 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 COIL2 Coil driver 2
9 COIL1 Coil driver 1
10 VEXT External power supply
11 DVS Driver supply voltage
12 VBatt Battery voltage
13 STANDBY Standby input
14 VS Internal power supply (5V)
15 RF Frequency adjustment
16 HIPASS DC decoupling
4684E–RFID–02/08 U2270B 3. Functional Description
3.1 Power Supply (PS)
Figure 3-1. Equivalent Circuit of Power Supply and Antenna Driver The U2270B can be operated with one external suppl y voltage or with two externally-stabilized supply voltages for an extended driver output volt age or from the 12V battery voltage of a vehi- cle. The 12V supply capability is achi eved 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. V EXT 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. VBatt Standby DGND VS PS DRV 18V 12 kΩ Internal supply COILx VEXT 25 kΩ DVS
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, V S, 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
3.2.2 Two-rail Operation
In this application, the driver voltage, D VS, 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 (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
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. V EXT 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. VBatt Standby +5V (stabilized) VSVEXTDVS VBatt Standby 5V (stabilized) VSVEXTDVS 7V to 8V (stabilized)
4684E–RFID–02/08 U2270B Figure 3-4. Battery Operation
3.3 Oscillator (Osc)
The frequency of the on-chip oscillator is controlled by a curr ent fed into the R F 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 k Ω is defined. For other frequencies, use the following formula: 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 VBatt StandbyVSVEXTDVS 7V to 16V Table 3-1. Characteristics of the Various Operation Modes Operation Mode External Components Required Supply-voltage Range Driver Output Voltage Swing Standby Mode Available One-rail operation 1 voltage regulator 1 capacitor 5V ±10% ≈ 4V No Two-rail operation 2 voltage regulators 2 capacitors 5V ±10% 7V to 8V 6V to 7V No Battery-voltage operation 1 transistor 2 capacitors Optional, for load dump protection: 1 resistor 1 capacitor 6V to 16V ≈ 4V Y es Rt kΩ[] 14375 f0 kHz[] RF Rf VS 2 kΩ
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 demodulati on. The upper cut-off frequency of the LPF depends on the selected oscillator frequency. The typical value is f Osc / 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 V pp. 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
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: 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. 210 kΩ 10 kΩ VBias + 0.4V VBias - 0.4V InputRS CIN fcut 1
4684E–RFID–02/08 U2270B Figure 3-7. Equivalent Circuit of Pin HIPASS
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 Schmitt trigger R RR R LPF HIPASS CHP VRef Ri OE 7 µA
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 Figure 3-10. Equivalent Circuit of Pin CFE MS 30 µA CFE 30 µA
4684E–RFID–02/08 U2270B
3.8 Function Table
- 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-coupl ing 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. The maximum transmission distance is also influenced by the accuracy of the antenna’s reso- nance. Therefore, the recommendations giv en 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 th e antenna design is provided in Section “Antenna Design Hints”. CFE MS COIL1 COIL2 Low Low High High Low High Low High High Low High High OE Output STANDBY U2270B Low Enabled Low Standby mode High Disabled High Active Table 4-1. Magnetic Coupling Magnetic Coupling Factor Appropriate Application k > 3% Free-running oscillator k > 1% Diode feedback k > 0.5% Diode feedback plus frequency altering k > 0.3% Diode feedback plus fine frequency tuning
4684E–RFID–02/08 U2270B The application of the U2270B includes the two capacitors C IN 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. 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 inde- pendent of other design issues except for one constellation. This constellation, consisting of diode feedback plus fine frequency t uning together with the two-ra il power supply, should be used if the transmission distance is d ≈ 10 cm.
4.1 Application 1
Application using few external components. Th is application is for intense magnetic coupling only. Figure 4-1. Application Circuit 1 Table 4-2. Recommended Capacitor Values Data Rate f = 125 kHz Input Capacitor (C IN) Decoupling Capacitor (C HP) f / 32 = 3.9 Kbits/s 680 pF 100 nF f / 64 = 1.95 Kbits/s 1.2 nF 220 nF 1.5 nF 1.2 nF 47 nF 47 µF RF MS OE STANDBY HIPASS OUTPUT CFEINPUT COIL1 COIL2 1.35 mHR GND Micro- controller DGND 1N4148 470 kΩ 110 kΩ DVS VBatt VDDVEXT VSS CHP CIN VS U2270B
4684E–RFID–02/08 U2270B
4.2 Application 2
Basic application using diode feedback. This application allows higher communication distances than .“Application 1” Figure 4-2. Application Circuit 2 1.5 nF 22 µF 22 µF 4.7 nF MS OE Output Standby CFE RF HIPASS Input I/O COIL1 COIL2 BC639 1.2 nF 1.35 mH Antenna GND 12V GND Micro- controller U2270B DGND 1N4148 4 × 1N4148 470 kΩ 68 kΩ 360Ω 43 kΩ100 kΩ 82Ω DVS VBattVS VDDVEXT VSS CHP CIN 75 kΩ 22 µF
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 Note: Application examples have not been examined fo r 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. 1.5 nF 22 µF 47 nF 4.7 nF MS OE Output Standby CFE RF HIPASS Input COIL1 COIL2 1 nF 1.5 mH Antenna GND GND Micro- controller U2270B DGND180 pF BC846 1N4148 4 × 1N4148 470 kΩ 68 kΩ 43 kΩ 1.5 kΩ 4.7 kΩ 100 kΩ 82Ω 100Ω DVS VBattVS VDDVEXT VSS CHP CIN 75 kΩ
4684E–RFID–02/08 U2270B 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 V Batt VS 16 V Operating voltage 8, 9, 10, 11, 14 VS, VEXT, DVS, Coil 1, Coil 2 –0.3 8 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 V Output current 10 I EXT 10 mA Output current 2 I OUT 10 mA Driver output current 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 6. Thermal Resistance Parameter Symbol Value Unit Thermal resistance SO16 R thJA 120 K/W 7. Operating Range All voltages are referred to GND (Pins 1 and 7) Parameter Pin Symbol Value Unit Operating voltage 12 V Batt 7 to 16 V Operating voltage 14 V S 4.5 to 6.3 V Operating voltage 10, 11 V EXT, DVS 4.5 to 8 V Carrier frequency 100 to 150 kHz
4684E–RFID–02/08 U2270B 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. 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 I out = 5 mA 2 V CEsat 400 mV Data output enable - Low-level input voltage - High-level input voltage 3V il Vih 2.4 0.5 V V Data input - Clamping level low - Clamping level high - Input resistance - Input sensitivity f = 3 kHz (square wave) Gain capacitor = 100 nF 4 V il Vih Rin SIN 10 3.8 220 V V kΩ mVpp Driver polarity mode - Low-level input voltage - High-level input voltage il Vih 2.4 0.2 V V Carrier frequency enable - Low-level input voltage - High-level input voltage il Vih 3.0 0.8 V V Operating current 5V application without load connected to the coil driver 10, 11, 12 and IS 4.5 9 mA Standby current 12V application 12 I St 30 70 µA VS - Supply voltage - Supply voltage drift - Output current 14 VS dVs/dT IS 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 I L = ±100 mA VS, VEXT, VBatt, DVS = 5V VBatt = 12V 8, 9 V DRV 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 IC active Standby mode V EXT dVEXT/dT IEXT IEXT 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 13 V il Vih 3.1 0.8 V V Oscillator - Carrier frequency RF resistor = 110 kΩ (“Application 2” ), REM 1(1) f0 121 125 129 kHz Low-pass filter - Cut-off frequency Carrier frequency = 125 kHz f cut 7k H z Amplifier gain C HP = 100 nF 30
4684E–RFID–02/08 U2270B 10. Package Information 9. Ordering Information Extended Type Number Package Remarks U2270B-MFPY SO16 Tube, Pb-free U2270B-MFPG3Y SO16 Taped and reeled, Pb-free Package: SO 16 Dimensions in mm specifications according to DIN technical drawings Issue: 1; 15.08.06 Drawing-No.: 6.541-5031.02-41 Pin 1 identity 16 9 0.2 5±0.2 3.8±0.1 6±0.2 3.7±0.1 9.9±0.1 8.89 0.4 1.27 0.1+0.15 1.4
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 4684E-RFID-01/08
- Put datasheet in a new template
- Section 3.4 “Low-pass Filter (LPF) on page 7: Typo removed
- Section 8 “Electrical Characteristics” on page 15: Parameter VS alignment corrected 4684D-RFID-09/06
- Put datasheet in a new template
- Pb-free logo on page 1 deleted
- Section 10 “Package Information” on page 16 changed
- Minor grammatical corrections and fixed broken cross references 4684C-RFID-12/05 • Last page: Legal sentence changed 4684B-RFID-09/05
- 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
4684E–RFID–02/08 Headquarters International Atmel Corporation
2325 Orchard Parkway
San Jose, CA 95131 USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Atmel Asia Room 1219 Chinachem Golden Plaza
77 Mody Road Tsimshatsui
Tel: (852) 2721-9778 Fax: (852) 2722-1369 Atmel Europe Le Krebs 8, Rue Jean-Pierre Timbaud BP 309 78054 Saint-Quentin-en-Yvelines Cedex France Atmel Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Product Contact Web Site www.atmel.com Technical Support rfid@atmel.com Sales Contact www.atmel.com/contacts Literature Requests www.atmel.com/literature Disclaimer: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to any intellectual property right is granted by this document or in connection with the sale of Atmel products. EXCEPT AS SET FORTH IN ATMEL ’S TERMS AND CONDI- TIONS OF SALE LOCATED ON ATMEL ’S WEB SITE, ATMEL ASSUMES NO LI ABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTOR Y WARRANTY RELATING TO ITS PRODUCTS INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICU LAR PURPOSE, OR NON-INFRINGEMENT. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE, SPECIAL OR I NCIDEN- TAL DAMAGES (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS, BUSINESS INTERRUPTION, OR LOSS OF INFORMATION) ARISING OUT OF THE USE OR INABILITY TO USE THIS DOCUMENT, EVEN IF ATME L HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Atmel makes no representations or warranties with respect to the accuracy or comp leteness of the contents of this document and reserves the rig ht to make changes to specifications and product descriptions at any time without notice. Atmel does not make any commitment to update the information contained her ein. Unless specifically provided otherwise, Atmel products are not suitable for, and shall not be used in, automotive applications. Atmel’s products are not int ended, authorized, or warranted for use as components in applications in tended to support or sustain life. © 2008 Atmel Corporation. All rights reserved. Atmel ®, logo and combinations thereof, IDIC ®, and others are registered trademarks or trade- marks of Atmel Corporation or its subsidiaries. Other terms and product names may be trademarks of others.