AM RF TRANSMITTER M ODULE. AM-TX1-XXX FEATURES • • • • • • • • • • MINIATURE MODULE (7.5 x 11.5 X 4.5mm) SAW CONTROLLED FREQUENCY STABILITY NO ADJUSTABLE COMPONENTS. TRANSMITTING RANGE UP TO 30 METRES. CMOS/TTL COMPATIBLE INPUT. CURRENT CONSUMPTION 2.5mA (typ). SINGLE SUPPLY VOLTAGE 2.5 -12V. COMPATIBLE WITH R.F. SOLUTIONS AM RECEIVER. MPT1340 LICENCE EXEMPT. AVAILABLE AS EITHER 418MHz OR 433MHz. APPLICATIONS • CAR ALARM KEYFOBS • GARAGE DOOR OPENERS • REMOTE TRANSMITTER ENCODERS • REMOTE GATE SYSTEMS DESCRIPTION The R.F. Solutions AM Transmitter module offers a miniature hybrid modular RF transmitter providing on-off keyed modulation, which can be used to transmit data from any standard CMOS/TTL source up to 1200 baud. The module is very simple to operate, requiring only two connections (see application circuit below). The module is also very efficient, using only 2.3mA (typ) which means that it may be driven directly from an encoder I/C or microcontroller. The output impedance has been designed to give optimum performance when coupled with a small antenna such as a tuned loop or short whip. The modules are compatible with the AM Receiver modules (AM -HRRn-XXX or AM-RRS2-XXX). The transmitter module is type approved to MPT1340 for use in general telemetry and telecommunications products, when used with the antenna as listed overleaf. APPLICATION CIRCUIT Driving TX1 from Current Source Signal from Encoder circuit Driving TX1 from - Current Sink Rd drive current drive Voltage + TX1 Module 220pF RF GND DS000012 Issue 1.3 Jul ‘99 RF GND drive Voltage Signal from Encoder circuit 1999 REG No 277 4001, ENGLAND. 220pF TX1 Module Rd drive current Page 1 AM RF TRANSMITTER M ODULE. AM-TX1-XXX Operation The application circuit shows how to drive the module. The module may be driven from either a current source or current sink. In both cases the dropper resistor is required to set the drive current. The maximum and minimum drive voltage for various dropper resistor values is shown below. For other voltages between 2.5 - 13.1V the values may be calculated using the following formula Min Rd = ( Max drive Voltage - 3 ) / 0.0046 The minimum drive voltage for a given resistor value may then be calculated as; Min drive Voltage = 2.2 + .003 * Rd Example: The max drive voltage is 5.5V. The min Rd is therefore 543 Ω. The nearest preferred value above this is 560 Ω. The min drive voltage with 560 Ω is 3.86V. ANTENNAS Two types of antenna may be used, a tuned loop, or a short whip. The tuned loop should be driven directly from the module. The whip should be driven via the specified tuning network. The module is not type approved for use with a 1/4 wave or helical type antenna. Short Whip Antenna Tuned Loop Antenna 90mm MAX ~ ~ Max 700mm2 1-5pF 1-5pF RF Ground RF Ground The tuned loop Ant is constructed from wire of 1-1.5mm DIA, or PCB track of 1.5-2.5mm width. The enclosed area of the loop shall not exceed 700mm2. The trimming capacitor should be used to tune the ant for max output. A 1.5 - 5pF cap is generally adequate. The short whip ant is constructed from a wire rod or PCB track of 90mm length. The 15nH inductor may be an SOIC component on the PCB, or an air cored solenoid of 0.8mm inside DIA, close wound with 9 turns of 0.56mm. The trimming capacitor should be used to tune the ant for max output. A 1.5 - 5pF cap is generally adequate. MECHANICAL DETAILS Width = 7mm, Height = 11.5mm, thickness: 4.5mm. +ve connection is shown by marking on body side Lead Pitch 5.08mm. 11.5mm +ve Side 7.5mm 5.08mm 4.5mm DS000012 Issue 1.3 Jul ‘99 1999 REG No 277 4001, ENGLAND. Page 2 AM RF TRANSMITTER M ODULE. AM-TX1-XXX TECHNICAL SPECIFICATION Absolute Maximums Voltage + ve to -ve -2.5 to 8.5o C Ambient temperature 20deg C Storage Temp ELECTRICAL CHARACTERISTICS Module Voltage (@ max drive) Module Voltage (@ min drive) Drive Current (@ max drive) Drive Current (@ min drive) Working Frequency Working Frequency Data Throughput Tuning Tolerance Radiated Power (ERP) (@ max drive V) Modulation Modulation Pulse width Operating Temperature MIN 8.8 6.7 5.2 4.2 3.6 3.2 2.8 2.5 -1 DRIVE VOLTAGE MAX 13.1 9.9 7.6 6.1 5.2 4.5 4.0 3.5 0.5 UNIT V V V V V V V V V -40 to +85o C MIN 417.925 TYPICAL 3.0 2.2 4.6 3.0 418.000 433.92 MAX 418.075 1200 +/-75 -6.0 ON-OFF 0.8 -10 +40 DIMENSION V V mA mA MHz MHz baud KHz dBm mSecs Deg Celsius RESISTOR VALUE (RD) Ω 2K2 1K5 1K 680 470 330 220 100 ‘off voltage’ LICENCE EXEMPTION This range of Radio transmitters is approved by the Department of Trade & Industry (D.T.I. Specification MPT1340) in the U.K., and therefore the user requires no radio operating licence in the U.K. Please note however the following requirements to comply with MPT1340; 1. All transmitters shall use integral antennas only. Receivers may use an external or integral antenna. An integral antenna is defined as one which is designed to be connected permanently to the transmitter or receiver without the use of an external feeder. The antenna shall be a tuned loop not exceeding 700mm2 enclosed area, or a whip not exceeding 90mm in length. 2. The equipment in which the module is used must carry an inspection mark located on the outside of the equipment which is clearly visible. It shall state “MPT1340 W.T. Licence Exempt”. The minimum dimensions of the mark shall be 10 x 15mm and the figure height shall be not less than 2mm. PART No AM-TX1-418 AM-TX1-433 DESCRIPTION Transmitter Module 418MHz Transmitter Module 433MHz Should you require further assistance, please call; R. F. Solutions Ltd., Unit 21, Cliffe Industrial Estate, South Street, Lewes, E Sussex, BN8 6JL. England. Tel +44 (0)1273 898 000. Fax +44 (0)1273 480 661. Email [email protected] http://www.rfsolutions.co.uk RF Solutions is a member of the Low Power Radio Association. Information contained in this document is believed to be accurate , however no representation or warranty is given and no liability is assumed by R.F. Solutions Ltd. with respect to the accuracy of such information. Use of R.F.Solutions as critical components in life support systems is not authorised except with express written approval from R.F.Solutions Ltd. DS000012 Issue 1.3 Jul ‘99 1999 REG No 277 4001, ENGLAND. Page 3