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TH71082 868/915MHz ASK Transmitter / LO Source Features ! Fully integrated, PLL-stabilized VCO ! Flexible frequency range from 800 MHz to 930 MHz ! ASK achieved by on/off keying of internal power amplifier ! FM possible with external varactor ! Wide power supply range from 2.2 V to 5.5 V ! High over-all frequency accuracy ! Very low standby current ! ! ! ! ! Adjustable output power range from -18 dBm to -2 dBm Adjustable current consumption from 6.2 mA to 12.5 mA Single-ended RF output Clock output for C drive Conforms to EN 300 220 and similar standard Ordering Information Part No. TH71082 Temperature Range -40 C to 85 C Package SOIC8 Application Examples ! ! ! ! ! ! Keyless car and central locking Low-power telemetry Alarm and security systems General digital data transmission General analog audio signal transmission Local oscillator signal generation Pin Description LF 1 8 VEE RO 2 ENTX 3 CKOUT 4 TH71082 7 OUT 6 VCC 5 PS/DATA TH71082 Data Sheet 3901071082 Page 1 of 10 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source General Description The TH71082 ASK transmitter IC is designed for applications in the European 868MHz industrialscientific-medical (ISM) band, according to the EN 300 220 telecommunications standard. It can also be used for any other system with carrier frequencies ranging from 800 MHz to 930 MHz (e.g. for applications in the US 915MHz ISM band). The transmitter's carrier frequency fc is determined by the frequency of the reference crystal fref that is used. The integrated PLL synthesizer ensures that each RF value, ranging from 800 MHz to 930 MHz, can be achieved by using a crystal with reference frequency according to: fref = fc/N, where N = 32 is the PLL feedback divider ratio. Theory of Operation General As depicted in Fig.1, the TH71082 transmitter consists of a fully integrated voltage-controlled oscillator (VCO), a divide-by-32 divider (div32), a phase-frequency detector (PFD) and a charge pump. An external loop filter at pin LF determines the dynamic behaviour of the PLL and suppresses reference spurious signals. The VCO's output signal feeds the power amplifier (PA). RF signal power Po can be adjusted in six steps from Po = -15 dBm to -1 dBm, either by changing the value of resistor R1 or by varying the voltage VPS at pin PS/DATA. The open-collector output (OUT) can be used to either drive a loop antenna or to feed a single-ended load impedance. This could be, for example /4 monopol antenna or a 50 output port. In any case, an impedance matching network should be added in order to achieve maximum available RF power. Bandgap biasing ensures stable operation of the IC at a power supply range of 2.2 V to 5.5 V. Clock Output The TH71082 feature a clock output (CKOUT) that can be used to drive a C. The frequency at CKOUT is fref/8. The clock output is slew-rate limited in order to keep spurious signal emission as low as possible. The voltage swing at CKOUT depends on the capacitive loading at this pin. It is approximate 2 Vpp at Cload = 5 pF ASK Modulation The TH71082 can be ASK-modulated by applying data directly at pin PS. This turns the PA on and off and therefore leads to an ASK signal at the output. LO Source Many applications require a stable RF source. For this purpose, the TH71082 can be used without modulation as an easy-to-use, PLL-stabilized, continuous wave (CW) generator. Frequency Modulation (FM) For FM operation an external varactor is required. It simply acts as a pulling capacitor connected in series to the crystal. Then the analog modulation signal, applied through a series resistor, directly modulates the XOSC. Mode Control Logic The mode control logic allows two different modes of operation as listed in the following table. The mode control pin ENTX is pulled-down internally. This guarantees that the whole circuit is shut down if this pin is left floating. ENTX Mode Description 0 1 TX disabled whole circuit in standby TX enable TX active Table 1: Modes of operation TH71082 Data Sheet 3901071082 Page 2 of 10 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source Block Diagram VCC OUT 7 PS/DATA 5 mode control PA ENTX 3 VCC 6 charge pump 8 VEE VCO div32 PFD LF 1 CKOUT 4 div 8 XOSC RO 2 Fig. 1: TH71082 block diagram with external components TH71082 Data Sheet 3901071082 Page 3 of 10 CX1 XTAL CF1 RF1 CF2 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source Pin Definition and Description Pin No. 1 LF Name I/O Type analog I/O LF 1 200 200 Functional Schematic Description connection to loop filter, charge pump output, VCO tuning input 5p 2 RO analog I/O 37k RO1 2 28p XOSC connection to XTAL, Colpitts type crystal oscillator 28p 3 ENTX input ENTX 3 1.1k mode control input, CMOScompatible with internal pulldown 4 CKOUT output CKOUT 4 200 clock output, CMOS-compatible 5 PS/DATA analog I/O 20A power-select and ASK input, high-impedance comparator logic PS/DATA 5 200 6 7 VCC OUT supply output VCC VCC positive power supply Power amplifier output, open collector OUT 7 VEE VEE 8 VEE ground negative power supply TH71082 Data Sheet 3901071082 Page 4 of 10 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source Technical Data Absolute Maximum Ratings Parameter Supply voltage Input voltage Input current Storage temperature Electrostatic discharge Symbol Vcc Vin Iin TSTG VESD human body model, MIL STD 833D method 3015.7 ENTX pin ENTX pin Condition Min -0.3 -0.3 -1.0 -40 -1.0 Max 7.0 VCC+0.3 1.0 150 +1.0 Unit V V mA C kV Normal Operating Conditions Parameter Supply voltage Operating temperature XOSC frequency VCO frequency Clock frequency Symbol Vcc Ta fref fc fclk set by the crystal fc = 32 * fref fclk = fref / 4 Condition Min 2.2 -40 25 800 3.12 Max 5.5 85 29 930 3.62 Unit V C MHz MHz MHz DC Characteristics all parameters under normal operating conditions, unless otherwise stated; typical values at Ta = 23 C and Vcc = 3 V Parameter Standby current Operating current Input HIGH voltage Input LOW voltage Input current Pull down current Symbol ISBY Icc VHIGH VLOW Iin Ipd Condition ENTX=0 ENTX=1, VPS=1.1V ENTX pin ENTX pin ENTX=0 ENTX=1 8 0.7*Vcc -0.3 -1 2 8 Min Typ 0.05 10 Max 0.1 11 Vcc+0.3 0.3*Vcc 1 15 Unit A mA V V A A TH71082 Data Sheet 3901071082 Page 5 of 10 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source AC Characteristics all parameters under normal operating conditions, unless otherwise stated; typical values at Ta = 23 C and Vcc = 3 V; ENTX = 1, VPS = 1.1V, fc = 868.3 MHz, test circuit shown in Fig. 2 Parameter Output power FM deviation Modulation frequency FM Data rate ASK Reference spurs Harmonic content Spurious output signal Phase noise VCO gain Charge pump current Clock voltage swing Start-up time Symbol Po fFM fmod RASK Pref Pharm Poff PN KVCO ICP VCKOUT ton Cload = 5pF from "all OFF" to any other mode @ fc fref @ 2fc , 3fc , 4fc VPS 0.1V @ fc 500kHz adjustable with varactor and VFM Condition Min Typ -4 6 5 40 -44 -40 -60 -87 300 260 2 0.9 Max Unit dBm kHz kHz kbit/s dBm dBm dBm dBc/Hz MHz/V A Vpp ms Output Power Selection typical values at Ta = 23 C and Vcc = 3 V: ENTX = 1, fc = 868.3 MHz, test circuit shown in Fig. 2 R1 / k R2 / k VPS / V Icc / mA Po / dBm Pharm / dBm 2 12.5 -2 -40 0 7.5 4.7 1.1 9.5 -5 -40 11 4.7 0.9 8.5 -8 -40 15 4.7 0.7 7.8 -11 -45 24 4.7 0.5 7.0 -15 -45 43 4.7 0.3 6.2 -18 -50 If the transmitter is operated at any supply voltage Vcc, the values for R1 and R2 can be calculated as allows: V R1 = R2 * cc - 1 V PS Crystal Parameter Parameter Crystal frequency Load capacitance Static capacitance Resonance resistance Spurious response Symbol fcrystal Cload C0 Rm aspur Condition fundamental mode, AT Min 25 10 Max 29 15 7 40 -10 Unit MHz pF pF dB TH71082 Data Sheet 3901071082 Page 6 of 10 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source Test Circuit L2 C1 L1 C3 Fig. 2: Test circuit for ASK with 50 matching network OUT C2 7 6 VCC PS 5 DATA VEE 8 OUT R2 CKOUT ENTX RO LF R1 1 2 3 CX RF1 CF2 CF1 XTAL C4 4 12 3 12 12 12 VCC ENTX GND Test circuit component list to Fig. 2 Part CF1 CF2 CX C1 C2 C3 C4 L1 L2 RF1 R1 R2 XTAL Size 0603 0603 0603 0603 0603 0603 0805 0603 0603 0603 0603 0603 HC49/S Value 4.7 nF 56 pF 100 pF 100 pF 6.8 pF 330 pF 33 nF 270 nH 12 nH 1 k See output power selection table See output power selection table 27.1344 MHz fundamental wave Tolerance 10% 10% 10% 5% 5% 10% 10% 5% 5% 10% 10% 10% 30ppm calibration 30ppm temp. loop filter capacitor loop filter capacitor XOSC capacitor Description impedance matching capacitor impedance matching capacitor blocking capacitor blocking capacitor impedance matching inductor impedance matching inductor loop filter resistor ASK power-select resistor, not requirement at CW mode ASK or CW mode power-select resistor crystal, Cload = 12 pF to 15 pF, C0, max = 7 pF, Rm, max = 40 TH71082 Data Sheet 3901071082 Page 7 of 10 CKOUT GND DATA GND Dec. 2001 Rev. 004 VCC GND TH71082 868/915MHz ASK Transmitter / LO Source Package Information E1 E 123 D A1 A e b L Fig. 6: SOIC8 (Small Outline Package) all Dimension in mm, coplanarity < 0.1mm D min max min max 4.80 4.98 0.189 0.196 E1 3.81 3.99 E 5.80 6.20 A 1.32 1.72 A1 0.10 0.25 e 1.27 b 0.36 0.46 L 0.41 1.27 0.016 0.050 0 8 0 8 all Dimension in inch, coplanarity < 0.004" 0.150 0.2284 0.060 0.0040 0.05 0.014 0.157 0.2440 0.068 0.0098 0.018 TH71082 Data Sheet 3901071082 Page 8 of 10 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source Your Notes TH71082 Data Sheet 3901071082 Page 9 of 10 Dec. 2001 Rev. 004 TH71082 868/915MHz ASK Transmitter / LO Source Your Notes Important Notice Devices sold by Melexis are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. Melexis makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Melexis reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with Melexis for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by Melexis for each application. The information furnished by Melexis is believed to be correct and accurate. However, Melexis shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interrupt of business or indirect, special incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of Melexis' rendering of technical or other services. (c) 2000 Melexis NV. All rights reserved. For the latest version of this document. Go to our website at www.melexis.com Or for additional information contact Melexis Direct: Europe and Japan: Phone: +32 1361 1631 E-mail: sales_europe@melexis.com All other locations: Phone: +1 603 223 2362 E-mail: sales_usa@melexis.com QS9000, VDA6.1 and ISO14001 Certified TH71082 Data Sheet 3901071082 Page 10 of 10 Dec. 2001 Rev. 004 |
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