ETC AM-TX-433

AM RF TRANSMITTER M ODULE.
AM-TX1-XXX
FEATURES
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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
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CAR ALARM KEYFOBS
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GARAGE DOOR OPENERS
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REMOTE TRANSMITTER ENCODERS
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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 sales@rfsolutions.co.uk
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