RXM-315-LC-S
RXM-418-LC-S
RXM-433-LC-S
WIRELESS MADE SIMPLE
®
LC SERIES RECEIVER MODULE DATA GUIDE
Covers Ultra-Compact S-Style (True SMD Version)
DESCRIPTION
0.14 in.
.630 in.
.812 in.
The LC Series is ideally suited for volume use in
OEM applications such as remote control,
security, identification, and periodic data transfer.
Available in 2 styles of compact SMD packages,
the LC-S receiver utilizes a highly optimized SAW
architecture to achieve an unmatched blend of
performance, size, efficiency and cost. When
paired with a matching LC Series transmitter, a
highly reliable wireless link is formed, capable of
transferring serial data at distances in excess of
300 feet. No external RF components, except an
antenna, are required, making design integration
straightforward.
PHYSICAL DIMENSIONS
TOP VIEW
FEATURES
■
■
■
■
Low Cost
No External RF Components Required
Low Power Consumption
Compact True Surface-Mount
Package
■
■
■
■
■
PINOUTS
Stable SAW-based Architecture
Outstanding Sensitivity
Supports Data Rates to 5,000bps
Direct Serial Interface
No Production Tuning
APPLICATIONS INCLUDE
■
Remote control / Keyless entry
■
Garage / Gate openers
■
Lighting control
■
Medical monitoring / Call systems
■
Remote industrial monitoring
■
Periodic data transfer
■
Home / Industrial automation
■
Fire / Security alarms
■
Wire Elimination
■
Long-range RFID
ORDERING INFORMATION
PART #
EVAL-***-LC
MDEV-***-LC
RXM-315-LC-P
RXM-418-LC-P
RXM-433-LC-P
RXM-315-LC-S
RXM-418-LC-S
RXM-433-LC-S
DESCRIPTION
Basic Evaluation Kit
Master Development Kit
Receiver 315MHZ (Pinned SMD)
Receiver 418MHZ (Pinned SMD)
Receiver 433MHZ (Pinned SMD)
Receiver 315MHZ (SMD)
Receiver 418MHZ (SMD)
Receiver 433MHZ (SMD)
*** Insert Frequency
Not covered in this manual
LC Receivers are supplied in tube
packaging - 40 pcs. per tube.
Revised 12/20/01
PERFORMANCE DATA–RXM-***-LC
ABOUT THESE MEASUREMENTS
The performance parameters listed
below are based on module
operation at 25°C from a 3VDC.
Figure 1 at the right illustrates the
connections necessary for testing
and operation. It is recommended
that all ground pads be connected to
the groundplane. The pads marked
NC have no physical connection and
are designed only to add support.
5VDC
200
External
Resistor
3VDC
1
2
3
4
5
6
7
8
NC
NC
NC
GND
VCC
PDN
NC
DATA
ANT
GND
NC
NC
NC
NC
NC
NC
16
15
14
13
12
11
10
9
Parameters
RXM-418-LC-S
Operating Voltage
w/Dropping Resistor
Current Continuous
Current in Sleep
Data Out Voltage
Logic Low
Designation
Min.
Typical
Max.
Units
Notes
V
CC
2.7
–
4.2
VDC
–
V
CC
4.7
–
5.2
VDC
3
I
CC
(V
CC
=3V)
4.0
5.0
7.0
mA
–
I
SLP
(V
CC
=3V)
–
700
930
µA
–
V
OL
Data Out Voltage
Logic High
0
–
0.2
VDC
–
V
OH
V
CC
-0.3
–
V
CC
VDC
–
Figure 1: Test/Basic Application Circuit
V
OH
Receive Frequency
Noise BW
2.7
3.4
V
CC
(
Note 5)
VDC
4
ABSOLUTE MAXIMUM RATINGS
Supply voltage V
CC
F
C
417.925
418
418.075
MHz
–
–
Sensitivity @10
-5
BER
Baud Rate
Settling Time
Parameters
RXM-433-LC-S
Operating Voltage
w/Dropping Resistor
Current Continuous
280
–
kHz
–
-0.3
-0.3
(SEE NOTES 3,4)
to
to
+4.2
+5.2
VDC
VDC
-92
-95
-100
dBm
1
100
–
5,000
bps
_
Operating temperature
Storage temperature
Soldering temperature
RF input, pin 16
Any input or output pin
-0.3
-30°C
to
+70°C
-45°C
to
+85°C
+225°C for 10 sec.
0 dBm
to
Vcc
5
7
10
mSec
2
Designation
Min.
Typical
Max.
Units
Notes
*NOTE*
Exceeding any of the limits of this section may lead to permanent
damage to the device. Furthermore, extended operation at these maximum
ratings may reduce the life of this device.
V
CC
2.7
–
4.2
VDC
–
V
CC
4.7
–
5.2
VDC
3
I
CC
(V
CC
=3V)
Typical
–
Max.
4.2
Units
VDC
Notes
–
Current in Sleep
Data Out Voltage
Logic Low
4.0
5.0
7.0
mA
–
Parameters
RXM-315-LC-S
Designation
V
CC
Min.
2.7
4.7
4.0
–
I
SLP
(V
CC
=3V)
–
700
930
µA
–
Operating Voltage
w/Dropping Resistor
Current Continuous
Current in Sleep
Data Out Voltage
Logic Low
V
OL
Data Out Voltage
–
5.0
700
5.2
7.0
930
VDC
mA
µA
3
–
–
Receive Frequency
Logic High
0
–
0.2
VDC
–
V
CC
I
CC
(V
CC
=3V)
I
SLP
(V
CC
=3V)
V
V
OL
OH
V
OH
V
CC
-0.3
–
V
CC
VDC
–
V
OH
2.7
3.4
V
CC
(
Note 5)
VDC
4
F
C
0
V -0.3
CC
433.845
–
–
V
OH
433.92
0.2
V
2.7
F
C
314.925
–
-92
100
3.4
315.0
280
-95
–
CC
433.995
VDC
VDC
V
CC
(
Note 5)
315.075
–
-100
5,000
VDC
MHz
kHz
dBm
bps
–
–
4
–
–
1
_
Noise BW
Sensitivity @10
-5
BER
Baud Rate
Settling Time
MHz
–
–
280
–
kHz
–
Data Out Voltage
Logic High
-92
-95
-100
dBm
1
100
–
5,000
bps
–
5
7
10
mSec
2
Receive Frequency
Noise BW
Sensitivity @10
-5
BER
Baud Rate
Settling Time
Notes:
1.
2.
3.
4.
5
7
10
mSec
2
5.
Page 2
For BER of 10
-5
at 4800 baud. Sensitivity is affected by antenna SWR. See Figure 3.
Time to valid data output.
*CRITICAL* In order to operate the device over this range it is necessary for a 200 resistor to be placed
in-line with VCC.
When operating from a 5 volt source it is important to consider that the output will swing to well less than
5 volts as a result of the required dropping resistor. Please verify that the minimum voltage will meet the
high threshold requirment of the device to which data is being sent.
Maximum output voltage measured after in-line dropping resistor.
Page 3
PHYSICAL PACKAGING
The receiver is packaged as a hybrid SMD module with sixteen pads spaced
0.100" on center. The castellated SMD package allows for easy prototyping or
hand assembly while maintaining full compatibility with automated pick-and-
place equipment. Modules are supplied in tube packaging.
SENSITIVITY vs. VSWR
(VSWR)
(VSWR)
10.0
6.0
5.0
4.0
3.0
2.5
2.0
1.5
1.0
TYPICAL PERFORMANCE GRAPHS
V
DATA
Supply current
(mA)
16
3.7
12
8
4
0.812"
0.630"
0.14"
LOT 2000
16
15
14
13
12
11
10
9
ANT
GND
NC
NC
NC
NC
NC
NC
NC
NC
NC
GND
VCC
PDN
NC
DATA
1
2
3
4
5
6
7
8
0 0.18 0.5 0.9 1.25 1.94 2.53 3.10 4.80
2.7
2.7
0
3
2.7
3.5
4
3
4.5
3.5
5
5.2 (V)
4 (V)
SENSITIVITY DECREASE (dB)
V
CC
Supply voltage
Figure 3: Sensitivity vs. VSWR
Figure 4: Consumption vs. Supply Voltage
Data Out
Bottom View
Figure 2: LC-S Series Receiver Package Dimensions
Data Out
PIN DESCRIPTIONS:
Pin 1, 2, 3, 7, 9, 10, 11, 12, 13, 14 - NO CONNECTION
Attach to an isolated pad to provide support for the module. Do not make any electrical
connection.
Carrier
Carrier
Figure 5: RF in vs. Receiver Response Time
Figure 6: Typical Receiver Turn-Off Time
Pin 4, 15 - GROUND
Connect to quiet ground or groundplane. It is internally connected to pin 8.
Original
Original
Pin 5 - POSITIVE SUPPLY
(V
CC
2.7 - 4.2 VDC *4.7 - 5.2 w/ external dropping resistor)
The supply must be clean (<20mVpp), stable and free of high-frequency noise. A supply
filter is recommended unless the module is operated from its own regulated supply or
battery. Please note that operation from 4.7 to 5.2 volts requires the use of an external
200 resistor placed in series with V .
CC
Received
Received
Pin 6 - POWER DOWN
Pull this line low to put the receiver in sleep mode (700 µA). Leave floating or pull high to
enable the receiver.
Figure 7: Original vs. Received Data
4,800bps 20% Duty Cycle
Figure 8: Original vs. Received Data
4,800bps 80% Duty Cycle
Pin 8 - DATA OUT
Internally pulled to V
CC
. Open collector data output with internal pullup to V
CC
. Recovered data
is output on this pin. Output voltage during a high bit will average V
CC
- 0.3V.
P
DN
Pin
Data Out
Pin 16 - RF IN
The receiver antenna connects to this input. It has nominal RF impedance of 50 and is
capacitively isolated from the internal circuitry.
Page 4
Figure 9: Power-On Settling Time
(Time to Valid Data)
Page 5
PRODUCTION GUIDELINES
The LC modules are packaged in a hybrid SMD package that supports hand- or
automated-assembly techniques. Since LC devices contain discrete
components internally, the assembly procedures are critical to ensuring the
reliable function of the LC product. The following procedures should be reviewed
with and practiced by all assembly personnel.
AUTOMATED ASSEMBLY
For high-volume assembly most users will want to auto-place the modules. The
receivers have been designed to maintain compatibility with reflow processing
techniques; however, due to the module's hybrid nature certain aspects of the
assembly process are far more critical than for other component types.
PAD LAYOUT
The following pad layout diagrams are designed to facilitate both hand and
automated assembly.
TX Layout Pattern Rev. 2
(Not to Scale)
Following are brief discussions of the three primary areas where caution must be
observed.
Reflow Temperature Profile
LC-S RX Layout Rev. 1
Compact SMD Version
LC-P RX Layout Pattern Rev. 3
Pinned SMD Version
(Not to Scale)
(Not to Scale)
0.100"
0.065"
.100
0.150
0.310"
0.610"
0.070"
0.775
.070
0.100"
0.070"
The single most critical stage in the automated assembly process is the reflow
process. The reflow profile below should be closely followed since excessive
temperatures or transport times during reflow will irreparably damage the modules.
Assembly personnel will need to pay careful attention to the oven's profile to
ensure that it meets the requirements necessary to successfully reflow all
components while still meeting the limits mandated by the modules themselves.
0.100"
300
250
Temperature (
o
C)
Figure 10: Recommended Pad Layout
Ideal Curve
Limit Curve
Forced Air Reflow Profile
RECEIVER HAND ASSEMBLY
The LC-S Receiver’s primary mounting
surface is sixteen pads located on the
bottom of the module. Since these pads
are inaccessible during mounting,
castellations that run up the side of the
module have been provided to facilitate
solder wicking to the module's under-
side. If the recommended pad place-
ment has been followed, the pad on the
board will extend slightly past the edge
of the module. Touch both the PCB pad
and the module castellation with a fine
soldering tip. Tack one module corner
first, then work around the remaining
attachment points using care not to
exceed the times listed below.
220
o
C
210
o
C
200
150
125
o
C
180
o
C
Soldering Iron
Tip
Reflow Zone
100
50
Ramp-up
1-1.5 Minutes
Soak Zone
20-40 Sec.
2 Minutes Max.
Preheat Zone
2-2.3 Minutes
Cooling
0
Solder
PCB Pads
Castellations
Figure 11: LC-S Soldering Technique
0
30
60
90
120
150
180
210
240
270
300
330
360
Time (Seconds)
Figure 12: Required Reflow Profile
Revision 2 - 11/98
Shock During Reflow Transport
Since some internal module components may reflow along with the components
placed on the board being assembled, it is imperative that the module not be
subjected to shock or vibration during the time solder is liquidus.
Washability
Absolute Maximum Solder Times
Hand-Solder Temp. TX +225°C for 10 Sec.
Hand-Solder Temp. RX +225°C for 10 Sec.
Recommended Solder Melting Point +180°C
Reflow Oven: +220° Max. (See adjoining diagram)
Page 6
The modules are wash resistant, but are not hermetically sealed. They may be
subject to a standard wash cycle; however, a twenty-four-hour drying time
should be allowed before applying electrical power to the modules. This will allow
any moisture that has migrated into the module to evaporate, thus eliminating the
potential for shorting during power-up or testing.
Page 7
MODULE DESCRIPTION
The RXM-LC-S is a low-cost, high-performance Surface Acoustic Wave (SAW)
based Carrier-Present Carrier-Absent (CPCA) receiver, capable of receiving
serial data at up to 5,000 bits/second. Its exceptional sensitivity provides
outstanding range at the maximum data rate. While oriented toward high-volume
automated production, the LC-S’s compact surface-mount package is also
friendly to prototype and hand production. When combined with a Linx LC series
transmitter, a highly reliable RF link capable of transferring digital data over line-
of-sight distances in excess of 300 feet (90m) is formed.
50
Ω
RF IN
(Ant.)
Band Select
Filter
pre-
amplifier
10.7 Mhz
AM Detector
Limiting Amp Ceramic Filter
Data Slicer
DATA
POWER SUPPLY REQUIREMENTS
The receiver module requires a clean, well-regulated
power source. While it is preferable to power the unit from
a battery, the unit can also be operated from a power
supply as long as noise and ‘hash’ is less than 20 mV. A
10 resistor in series with the supply followed by a 10µF
tantalum capacitor from V
CC
to ground will help in cases
where the quality of supply power is poor. Please note that
operation from 4.7 to 5.2 volts requires the use of an
external 200 resistor placed in series with V
CC
.
10R
THE DATA OUTPUT
Gilbert Cell
Mixer/Amp
10.7 Mhz
Bandpass Filter
Figure 15: Supply Filter
SAW Local Oscillator
A CMOS-compatible data output is available on pin 8. This output is normally used to
drive directly a digital decoder IC or a microprocessor that is performing the data
decoding. The receiver’s output is internally qualified, meaning that it will only
transition when valid data is present. In instances where no carrier is present the
output will remain low. Since a UART utilizes high marking to indicate the absence of
data, a designer using a UART may wish to insert a logic inverter between the data
output of the RXM-LC-S and the UART.
Figure 13: LC Series Receiver Block Diagram
THEORY OF OPERATION
The RXM-LC-S is designed to recover
data sent by a CPCA transmitter. This
type of AM modulation is often referred
Data
to by other designations including CW
and OOK. As the CPCA designation
suggests, this type of modulation
Carrier
Carrier
represents a logic low ‘0’ by the
absence of a carrier and a logic high ‘1’
by the presence of a carrier. This
Figure 14: CPCA (AM) Modulation
modulation method affords numerous
benefits. Two most important are: 1) Cost-effectiveness due to design simplicity
and 2) Higher output power and thus greater range in countries (such as the US)
which average output power measurements over time. Please refer to Linx
application note #00130 for a further discussion of modulation techniques
including CPCA.
The LC series utilizes an advanced single-conversion superhet design which
incorporates a SAW device, high IF frequency and multi-layer ceramic filters.
The SAW device has been in use for more than a decade but has only recently
begun to receive the widespread acclaim its outstanding capabilities deserve. A
SAW device provides a highly accurate frequency source with excellent
immunity to frequency shift due to age or temperature. The use of SAW devices
in both the LC transmitter and receiver modules allows the receiver’s pass
opening to be quite narrow, thus increasing sensitivity and reducing
susceptibility to near-band interference. The quality of components and overall
architecture utilized in the LC series is unusual in a low-cost product and is one
of the primary reasons the LC receivers are able to outperform even far more
expensive products.
Page 8
It is important to realize that the data output of the receiver may be subject to some
pulse stretching or shortening. This is caused by a combination of oscillator start-up
time on the transmitter and ring-down time in the receiver’s ceramic filter. It is
important to consider this effect when planning protocol. To learn more about protocol
considerations for the LC series we suggest you read Linx applications note #00232.
RECEIVING DATA
Once a reliable RF link has been established, the challenge becomes how to
effectively transfer data across it. While a properly designed RF link provides
reliable data transfer under most conditions, there are still distinct differences from
a wired link that must be addressed. Since the RXM-LC-S modules do not
incorporate internal encoding/decoding, a user has tremendous flexibility in how data
is handled.
It is always important to separate what type of transmissions are technically
possible from those that are legally allowable in the country of intended operation.
You may wish to review application notes #00125 and #00140 along with Part 15
Sec. 231 for further details on acceptable transmission content.
Another area of consideration is that of data structure or protocol. If unfamiliar with
the considerations for sending serial data in a wireless environment, you will want
to review Linx application note #00232 (Considerations for sending data with the LC
series). These issues should be clearly understood prior to commencing a
significant design effort.
If you want to transfer simple control or status signals such as button presses or
switch closures, and your product does not have a microprocessor on board your
product or you wish to avoid protocol development, consider using an encoder and
decoder IC set. These chips are available from a wide range of manufacturers
including: Microchip (Keeloq), Holtek (available directly from Linx), and Motorola.
These chips take care of all encoding, error checking, and decoding functions and
generally provide a number of data pins to which switches can be directly
connected. In addition, address bits are usually provided for security and to allow
the addressing of multiple receivers independently. These IC’s are an excellent way
to bring basic Remote Control/Status products quickly and inexpensively to market.
Additionally, it is a simple task to interface with inexpensive microprocessors such
as the Microchip PIC or one of many IR, remote control, DTMF, and modem IC’s.
Page 9
