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| Features * Very High Transmitting Frequency Accuracy Compared to SAW Solutions (Enables Receivers at Lower Bandwidth than with SAW Resonators) * Lower Cost than the Usual Discrete Solutions Using SAW and Transistors * Supply Voltage 2.2 V to 4.0 V in the Temperature Range of -40C to 85C * XTO Output for Clocking the Microcontroller, Thereby Together with the ATAR090 or ATAR890 Results in the Optimum System Cost-effectiveness * One-chip Solution with Minimum External Circuitry * Very Small SSO16 Package, Pitch 0.635, 150 mil * "Single-ended Open-collector" Output (Same Antennas Can Be Used as in Discrete Solutions, Simpler Adaptation of Magnetic Loop Antennas) * ESD Protection According to MIL-STD.883 (4 KV HBM) Except Pins XTO1/ 2, ANT and LF UHF ASK Transmitter U2745B Electrostatic sensitive device. Observe precautions for handling. Description The U2745B is a PLL transmitter IC which has been especially developed for the demands of RF low-cost data transmission systems at data rates up to 20 kBaud. The transmitting frequency range is 310 MHz to 440 MHz. It can be used in ASK systems. The main applications of the U2745B are in the areas of outside temperature metering, socket control, garage door opener, consumption metering, light/fan or aircondition control, jalousies, wireless keyboard and various other consumer market applications. Rev. 4734A-RKE-11/03 Figure 1. System Block Diagram UHF ASK Remote control transmitter 1 Li cell UHF ASK Remote control receiver U2745B Encoder ATARx9x XTO PLL U3745BM Demod. Control 1...3 Microcontroller Keys IF Amp Antenna Antenna VCO PLL XTO Power amp. LNA VCO Figure 2. Block Diagram ASK OR GND EN PWRSET Power up VCC PWRVCC VCO CLK PA ANT f GND PWRGND1 64 LFVCC PWRGND2 f n XTO XTO1 LFGND LF NC U2745B 2 U2745B 4734A-RKE-11/03 U2745B Pin Configuration Figure 3. Pinning SSO16 ASK 1 16 GND EN 2 15 PWRSET VCC 3 14 PWRVCC CLK 4 13 ANT U2745B GND 5 12 PWRGND1 LFVCC 6 11 PWRGND2 LFGND 7 10 XTO1 LF 8 9 NC Pin Description Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Symbol ASK EN VCC CLK GND LFVCC LFGND LF NC XTO1 PWRGND2 PWRGND1 ANT PWRVCC PWRSET GND Function Modulation input ASK Enable input Supply voltage Clock output Ground Supply voltage VCO VCO ground Circuit PLL loop Not connected Connection for crystal Power GND2 Power GND1 RF output Supply voltage power amplifier Applied to VCC Ground 3 4734A-RKE-11/03 General Description The fully integrated VCO and the "single-ended open-collector" output allow particularly simple, low-cost RF miniature transmitters to be assembled. The single-ended output enables a considerably simplified adaptation of both a magnetic loop antenna of any form or a l/4 antenna. This is because the load impedance must not be balanced as would be the case with a differential output. The XTO's frequency can be selected to be either 13.56 MHz or 9.844 MHz (USA). At these frequencies, crystals have a very fast start-up time (< 1.5 ms), whereby a wait time of 5 to 10 ms is required until the transmitter IC is locked. This means that the processor does not need to poll a lock detect output. Functional Description ASK Transmission The U2745B is activated by EN = VS. VASK must remain 0 V for 5 ms, then the output power can be modulated by means of pin ASK. VEN remains = VS during the transmission of the message. The ASK input activates the power amplifier and the PLL. The clock of the crystal oscillator can be used for clocking the microcontroller. The ATAR090 and ATAR890 have the special feature of starting with an integrated RC oscillator to switch on the U2745B with VEN = VS. 5 ms later, the 3.39-MHz clock frequency is present, so that the message can be sent with crystal accuracy. The following component values are recommendations for a typical application. C4, C5, and C6 are block capacitors. The values of these capacitors depend on the board layout. C4 = 1 nF, C5 = 1 nF, and C6 = 22 nF are typically used here. For C5, the impedance between f = 100 MHz and f = 1 GHz should be as low as possible. CLoop1 and CLoop2 are selected so that the antenna oscillates in resonance and the adaptation to the appropriate impedance transformation is possible. L F e e d is an inductor for the antenna's DC current supply. A typical value is LFeed = 220 nH. LFeed can be either printed on the PC board or be a discrete component. Take-over of the Clock Pulse in the Microcontroller Application Circuit Output Power Measurement The following output network (see Figure 4 on page 5) can be used for output power evaluation, the exact values of L10 and C10 are dependent on the layout. L10 and C10 form the transformation network to adopt the output impedance of the IC to 50 W. The following table shows the values for an output power of 2 mW and an RPWRSET = 1.2 kW. Table 1. Transformation Network f/MHz 315 433.92 C10/pF 2.7 1.8 L10/nH 56 33 ZLoad_opt/W 260 + j330 185 + j268 4 U2745B 4734A-RKE-11/03 U2745B Figure 4. Measurement Output Network VS PWRVCC L10 ANT C10 50 W ZLoad-opt Figure 5. Application Circuit +VS = 2.2 ... 4.0 V ASK ASK 1 GND OR Power up VCO PA 16 PWRSET CLoop2 R PWRSET EN EN 2 VCC C6 3 CLK 4 15 PWRVCC 14 ANT 13 CLK 3.39 MHz C4 LFeed GND 5 LFVCC 6 C5 LFGND 7 R4 C1 LF 8 C2 f 64 f n PWRGND1 12 PWRGND2 11 CLoop1 XTO XTO1 10 13.56 MHz U2745B NC 9 C3 Antenna 5 4734A-RKE-11/03 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. Parameters Symbol Min. Max. Unit Supply voltage Power dissipation Junction temperature Storage temperature Ambient temperature VS Ptot Tj Tstg Tamb -55 -40 6 250 150 125 85 V mW C C C Thermal Resistance Parameters Symbol Value Unit Junction ambient RthJA 180 K/W Electrical Characteristics All parameters are refered to GND (pin 5), VS = 3 V, Tamb = 25C, unless otherwise specified The possible operating ranges refer to different circuit conditions: VS = 2.2 V to 4.0 V at Tamb = -40C to +85C Parameters Test Conditions Symbol Min. Typ. Max. Unit Supply current (power down) VASK, VFSK 0.3 V, VS < 3.6 V ISoff ISon IStransmit PRef DPRef 2 4.7 10 1 3 1.5 10 6.2 12.5 5 A mA mA dBm dB Supply current (power up, output OFF) VASK = GND, VEN = VS, VS = 3 V Supply current (power up, output ON) VASK = VS, VS = 3 V, RPWRSET = 1.2 kW Output power Output power variation for f = 315 MHz compared to f = 433.92 MHz VS = 3 V, Tamb = 25C, f = 433.92 MHz RPWRSET = 1.2 kW f = 315 MHz Pout = PRef + DPRef at Pout = 2.0 mW, the load impedance must be selected to meet the Vout maximum requirement, the supply current is not dependent on the load impedance tolerance fo (n fPC) where fPC = 6.78 MHz Load capacitance at CLK 3 pF f = 230 MHz to 470 MHz f < 230 MHz, f > 470 MHz Crystal frequency = 13.56 MHz For best LO noise Loop filter components: C2 = 3.9 nF, C1 = 15 nF, R4 = 220 W Referring to the phase comparator fPC = 6.78 MHz at 1 MHz at 36 MHz Maximum peak output antenna voltage Voutmax VS - 0.7 V V(peak) Spurious emission Em Em fXTO BLoop PNPLL PNVCO PNVCO 13.56 30 ppm 13.56 -40 -58 13.56 + 30 ppm dBC dBC MHz Oscillator frequency XTO Loop bandwidth 100 kHz Phase noise PLL Phase noise VCO -111 -90 -122 -105 dBC/Hz dBC/Hz 6 U2745B 4734A-RKE-11/03 U2745B Electrical Characteristics (Continued) All parameters are refered to GND (pin 5), VS = 3 V, Tamb = 25C, unless otherwise specified The possible operating ranges refer to different circuit conditions: VS = 2.2 V to 4.0 V at Tamb = -40C to +85C Parameters Test Conditions Symbol Min. Typ. Max. Unit Frequency range of the VCO Clock output (CMOS microcontroller compatible) Load capacitance at CLK Series resonance R of the crystal ASK modulation frequency rate CLK output - Output current Low - Output current Low - Output current High - Output current High ASK input - Low level input voltage - High level input voltage - Input current High Enable ASK - Low level input voltage - High level input voltage - Input current High fXTO = 13.56 MHz fXTO = 9.84 MHz Duty cycle of the modulation signal = 50% VCLK = 0.2 VS VCLK = 0.3 VS VCLK = 0.8 VS VCLK = 0.7 VS fVCO Clkout CCLK Rs Rs fmodASK Iol Iol Ioh Ioh VASKl VASKh IASKh VEN VFSKl VFSKh IFSKh 310 fout/128 440 MHz MHz 10 80 100 0 20 pF W kHz 150 200 -150 -200 100 0.3 A A A A V V A V V A 1.7 140 0.3 1.7 140 7 4734A-RKE-11/03 Ordering Information Extended Type Number Package Remarks U2745B-MFB U2745B-MFBG3 SSO16 SSO16 Tube Taped and reeled Package Information 8 U2745B 4734A-RKE-11/03 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 1150 East Cheyenne Mtn. Blvd. Colorado Springs, CO 80906, USA Tel: 1(719) 576-3300 Fax: 1(719) 540-1759 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60 Biometrics/Imaging/Hi-Rel MPU/ High Speed Converters/RF Datacom Avenue de Rochepleine BP 123 38521 Saint-Egreve Cedex, France Tel: (33) 4-76-58-30-00 Fax: (33) 4-76-58-34-80 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 ASIC/ASSP/Smart Cards Zone Industrielle 13106 Rousset Cedex, France Tel: (33) 4-42-53-60-00 Fax: (33) 4-42-53-60-01 1150 East Cheyenne Mtn. Blvd. Colorado Springs, CO 80906, USA Tel: 1(719) 576-3300 Fax: 1(719) 540-1759 Scottish Enterprise Technology Park Maxwell Building East Kilbride G75 0QR, Scotland Tel: (44) 1355-803-000 Fax: (44) 1355-242-743 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 Literature Requests www.atmel.com/literature Disclaimer: Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company's standard warranty which is detailed in Atmel's Terms and Conditions located on the Company's web site. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel's products are not authorized for use as critical components in life support devices or systems. (c) Atmel Corporation 2003. All rights reserved. Atmel (R) and combinations thereof are the registered trademarks of Atmel Corporation or its subsidiaries. Other terms and product names may be the trademarks of others. Printed on recycled paper. 4734A-RKE-11/03 |
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