H
IGH
P
ERFORMANCE
RF MODULE
TXM-418/433-RM
RM SERIES TRANSMITTER MODULE DATA GUIDE
DESCRIPTION:
The LINX TXM-XXX-RM Series is an advanced ultra-
compact SAW-based transmitter module.When paired
with a Linx Technologies RM Series receiver, the units
create a highly reliable link c a p a ble of tra n s fe r ri n g
analogue or high-speed digital data at distances in
excess of 500 ft. L i ke all Linx modules, the RM
S e ries needs no production tuning or adjustment
and requires no ex t e rnal RF components (ex c e p t
Physical Outline
an antenna). O b s e rving simple design ru l e s, the
module is easily integrated even by engineers
lacking previous RF ex p e ri e n c e.
FEATURE HIGHLIGHTS:
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Compact SIP-style mounting
No production tuning or setup
Direct analog or digital input
Precision SAW-stabilized FM/FSK modulation
Supports high data rates (up to 10 Kbps)
Wide supply range (5.9-9 vDC)
Low power consumption (6mA Typical)
Wide operating temperature range
APPLICATIONS INCLUDE:
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Remote Control / Access Control
Remote Monitoring / Telemetry
Medical Alert
ORDERING INFORMATION
Remote Industrial Process Monitoring
PART #
DESCRIPTION
Periodic Data Transfer
MDEV-418-RM Evaluation Kit 418 MHz
TXM-418-RM-** Transmitter 418 MHz
Lighting Control
RXM-418-RM-** Receiver 418 MHz
Garage/Gate Openers
MDEV-433-RM Evaluation Kit 433 MHz
TXM-433-RM-** Transmitter 433 MHz
Security / Fire Alarms
RXM-433-RM-** Receiver 433 MHz
Wire Elimination
** Insert TB for Tube Packaging
Revised 2/8/00
MODULE DESCRIPTION
The RM Series is a SAW-(Surface Acoustic Wave) based transmitter designed
to be utilized in combination with a matching RM Series receiver. By adding a
simple antenna, the pair can transfer serial data at distances well in excess
of 500 fe e t . The range of the RF link is widely va ri a ble and depends upon
m a ny factors including the type of antenna employed and the opera t i n g
e nv i r o n m e n t . The 500 ft. quoted range is a conservative operating distance
over open ground using 1/4-whip antennae at both ends of the link at 5 feet
above the ground. Use of a less efficient antenna or adverse environmental
factors such as interference, obstacles, or multipath can substantially reduce
the link’s reliable working range. Slowing the data rate or utilizing a directional
antenna (especially on the receiver) can provide increased performance but
m ay not comply with licensing requirements. It is recommended that yo u r
individual application be rev i ewed with Linx prior to entering production or
seeking approvals.
figure 1: LINX-TX block diagram
THE SAW BASED DESIGN ADVANTAGE
The SAW (Surface Acoustic Wave) device provides a highly accura t e
frequency source with excellent immunity to frequency shift due to age or
t e m p e ra t u r e. By using a SAW to insure accurate frequency control on the
transmitter module the receiver’s pass opening can be quite narrow, resulting
in outstanding sensitivity and greater immunity to interfering signals. In order
to frequency modulate this carrier the SAW is externally pulled to obtain the
necessary deviation.
By employing a SAW on both the RM transmitter and receiver the units provide
an excellent performance rivaling far more complex and costly systems. The
S AW dev i c e, in combination with advanced design and manu fa c t u ri n g
techniques, has made it possible to dramatically reduce the size and cost of
an RF link while enhancing its perfo rm a n c e. The end user benefits from
improved product range and reliability and the OEM manufacturer from lower
cost and simpler manufacturing procedures.
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PHYSICAL PACKAGING
The transmitter is packaged as a hybrid SIP module with five pins spaced 0.1
in. on center.The SIP package allows easy accommodation of both hori zo n t a l
and vertical mounting requirements into a highly compact package. Its leaded
design allows for easy prototyping and simple integration into through-hole
and surface-mount designs. If the module will be bent and laid flush on the
circuit board, a pad of silicon or other adhesive should be used to hold it in
place.
figure 2: Mechanical dimensions
PIN DESCRIPTION
Pin 1
GND
Pin 2
RF OUT
Pin 3
Vcc
Pin 4
GND
Pin 5
DATA IN
Connect to common ground-plane.
For connection to external antenna. Output impedance is 50Ω.
Positive supply pin, supply voltages from +5.9 to +9 volts may be
used.
Connect to common ground-plane.
Analog or digital input. Should be dri ven by the same supply
voltage as the module. Usually interfaced with a CMOS logic
level device. Should never exceed Vcc.
WHAT EXTERNAL COMPONENTS ARE REQUIRED ?
The RM Series transmitter requires only a supply vo l t a g e, an ex t e rnal antenna
and analog or digital input. Production adjustment or tuning is not required.
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PERFORMANCE DATA – RM SERIES TRANSMITTER
Performance Data Pa r a m e t e rs :
Ambient temperature:
Supply voltage:
Test circuit:
Parameter
Operating supply range (Vcc)
Supply current
Vcc = 6.0V
Vcc = 9.0V
20°C
+8 volts, unless noted otherwise
configured as shown in figure 3
Min.
5.9
3.0
5.0
-4
-80
-95
15
DC
100
0vDC to Vcc
<=5Kbps
Typical
6.0
6.0
10.0
-1
–
–
25
–
–
Max
9.0
10.0
17.0
+4
+80
95
40
10
10,000
Measure
Volts
mA
mA
dBm
KHz
KHz
KHz
KHz
BPS
Notes
–
–
–
1
–
2
3
3
4
Field strength of fundamental Vcc = 6.0V
Transmit frequency
Initial frequency accuracy
Overall frequency accuracy
Spurious radiation
FM deviation (+/-)
Modulation Bandwidth (-3dB) analog
Digital data rate
Data input voltage
Max. data rate
RM Modules are available in 418 & 433.92 MHz
Capable of meeting FCC Par t 15
Notes:
1 Into 50Ω load.
2 Supply 5.9 to 9 volt, temp -10˚ to +55˚ C.
3 2 KHz square wave, 0 to Vcc.
4 High or low pulse.
figure 3: LINX RM Series test circuit
Absolute Maximum Ratings:
Supply voltage Vcc
Modulation input
Operating temperature
Storage temperature
pin 3
pin 5
-0.7 to +12 volts
-0.7 to +12 volts
-10°C to +55°C
-40°C to +100°C
*NOTE*
Exceeding any of the limits of this section may lead to permanent damage to the
device. F u rt h e r m o r e, extended operation at these maximum ratings may reduce the life of
this device.
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figure 4: Typical performance curves
POWER SUPPLY REQUIREMENTS
The transmitter module requires a clean, well-regulated voltage. While it is
p r e fe ra ble to power the unit from a battery, the unit can also be powered from
a power supply as long as noise and ‘ h a s h ’ is less than 20mV. A 10µF
capacitor to ground on pin 5 (Vcc) and a 10Ω series resistor will help in cases
where the quality of supply power is poor.
The module is not reverse polarity protected. R everse supply voltages will
cause permanent damage. External polarity protection is recommended.
Figure 5: Suggested supply filter
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