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| U2745B UHF ASK Transmitter Description The U2745B is a PLL transmitter IC which has been specially 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. Electrostatic sensitive device. Observe precautions for handling. Features D Supply voltage 2.2 V to 4.0 V in the temperature range -40C to 85C D One-chip solution with minimum external circuitry D Lower cost than the usual discrete solutions using SAW and transistors D Very small SSO16 package, pitch 0.635, 150 mil D "Single-Ended Open-Collector" output (same antennas can be used as in discrete solutions, simpler adaptation of magnetic loop antennas) D XTO output for clocking the mC, thereby together with M44C090 or M44C890 the optimum system cost-effectiveness D Very high transmitting frequency accuracy compared to SAW solutions. This enables receivers at lower bandwidth than is possible with SAW resonators. D ESD protection according to MIL-STD.883 (4KV HBM) except Pins XTO1/ 2, ANT and LF System Block Diagram UHF ASK Remote control transmitter UHF ASK Remote control receiver 1 Li cell U2745B PLL U3745BM Demod. Control 1...3 mC Keys Encoder M44Cx9x XTO IF Amp Antenna Antenna VCO PLL XTO Power amp. LNA VCO Figure 1. System block diagram Order Information Extended Type Number U2745B-MFB U2745B-MFBG3 Package SSO16 SSO16 Remarks Tube Taped and reeled Rev. A2, 28-Sep-00 1 (7) U2745B Pin Description ASK 1 EN 2 3 4 16 15 14 13 GND PWRSET PWRVCC ANT PWRGND1 VCC CLK GND U2745B 5 12 11 10 9 Figure 2. Pinning SSO16 LFVCC 6 LFGND 7 LF 8 PWRGND2 XTO1 n.c. 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 n.c. 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 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 n.c. U2745B 14919 Figure 3. Block diagram 2 (7) Rev. A2, 28-Sep-00 U2745B General Description The fully integrated VCO and the "single-ended opencollector" 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 at 13.56 MHz or USA 9.844 MHz. 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. Application Circuit The following component values are recommendations for a typical application. C4, C5, C6 are block capacitors. The values of these capacitors depend on the board layout. C4 = 1 nF, C5 = 1 nF, 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, CLoop2 are selected so that the antenna oscillates in resonance and the adaptation to the appropriate impedance transformation is possible. LFeed 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. Further information regarding the application is provided in the description of the "RKE Design Kit". 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 transmission of the message. The ASK input activates the power amplifier and the PLL. Output Power Measurement The following output network (see figure 4) can be used for output power evaluation, the exact values of L10, C10 are dependent on the layout. L10, C10 is 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. f/ MHz 315 433.92 C10/ pF 2.7 1.8 L10/ nH 56 33 VS PWRVCC L10 ANT C10 50 W 15009 Take-Over of the Clock Pulse in the C The clock of the crystal oscillator can be used for clocking the C. The M44C090 and M44C890 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. ZLoad_opt/ W 260 + j330 185 + j268 ZLoad-opt Figure 4. Measurement output network Rev. A2, 28-Sep-00 3 (7) U2745B +VS= 2.2...4.0V ASK EN ASK 1 EN 2 VCC 3 CLK 4 GND 5 LFVCC 6 LFGND 7 R4 C1 LF 8 OR Power up VCO f 64 f n XTO PA GND 16 PWRSET 15 PWRVCC 14 ANT 13 PWRGND1 12 PWRGND2 11 XTO1 10 n.c. 9 13.56MHz CLoop2 RPWRSET LFeed C6 CLK 3.39MHz C4 CLoop1 C5 C3 U2745B C2 Antenna Figure 5. Application circuit Absolute Maximum Ratings Parameters Supply voltage Power dissipation Junction temperature Storage temperature Ambient temperature Symbol VS Ptot Tj Tstg Tamb Min. Typ. Max. 6 250 150 125 85 Unit V mW C C C -55 -40 Thermal Resistance Parameters Junction ambient Symbol RthJA Value 180 Unit K/W 4 (7) Rev. A2, 28-Sep-00 U2745B 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 @ Tamb = -40C to +85C Parameters Supply current (power up, output OFF) Supply current (power up, output ON) Output power Test Conditions / Pins VASK = GND, VEN = VS, Vs = 3 V VASK = VS, VS = 3 V RPWRSET = 1.2 kW VS = 3 V, Tamb = 25C, f = 433.92 MHz RPWRSET = 1.2 kW f = 315 MHz Symbol ISoff ISon IStransmit 10 12.5 Min. Typ. 2 4.7 Max. 10 6.2 Unit A mA mA Supply current (power down) VASK, VEN v 0.3 V, VS < 3.6 V PRef DPRef 1 3 1.5 5 dBm dB Output power variation for f = 315 MHz compared to f = 433.92 MHz Maximum peak output antenna voltage Pout = PRef + DPRef @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. Voutmax VS - 0.7 V V(peak) Spurious emission fo n x fPC (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 Em Em fXTO 13.56 - 50 ppm -40 -58 13.56 100 13.56 +50 ppm dBC dBC Oscillator frequency XTO MHz kHz Loop bandwidth For best LO noise Loop filter components: C2 = 3.9 nF, C1 = 15 nF, R4 = 220 W @ 1 MHz @ 36 MHz BLoop Phase noise VCO Frequency range of the VCO Clock output (CMOS C 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 PNVCO PNVCO fVCO Clkout CCLK 310 -90 -122 440 fout/128 10 80 100 0 20 dBC/Hz MHz MHz pF W W kHz fXTO = 13.56 MHz fXTO = 9.84 MHz Duty cycle of the modulation signal = 50% VCLK = 0.2 x VS VCLK = 0.3 x VS VCLK = 0.8 x VS VCLK = 0.7 x VS Rs Rs fmodASK Iol Iol Ioh Ioh 150 200 -150 -200 100 mA mA mA mA Rev. A2, 28-Sep-00 5 (7) U2745B Parameters 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 Test Conditions / Pins Symbol VASKl VASKh IASKh VEN VFSKl VFSKh IFSKh Min. Typ. Max. 0.3 1.7 140 0.3 1.7 140 Unit V V mA V V mA Package Information Package SSO16 Dimensions in mm 5.00 max 5.00 4.80 1.40 0.2 0.25 0.635 4.45 16 9 0.25 0.10 3.95 max 5.2 4.8 6.2 5.8 technical drawings according to DIN specifications 13045 1 8 6 (7) Rev. A2, 28-Sep-00 U2745B Ozone Depleting Substances Policy Statement It is the policy of Atmel Germany 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. Atmel Germany GmbH 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. Atmel Germany GmbH can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain such substances. 9. 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 Atmel Wireless & Microcontrollers products for any unintended or unauthorized application, the buyer shall indemnify Atmel Wireless & Microcontrollers 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. Data sheets can also be retrieved from the Internet: http://www.atmel-wm.com Atmel Germany GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 (0)7131 67 2594, Fax number: 49 (0)7131 67 2423 Rev. A2, 28-Sep-00 7 (7) |
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