RXD-315-KH2
RXD-418-KH2
RXD-433-KH2
WIRELESS MADE SIMPLE ®
KH2 SERIES RECEIVER / DECODER DATA GUIDE
DESCRIPTION
The KH2 Series is ideally suited for volume use
in OEM applications such as remote control /
1.430"
command and keyless entry. It combines a
high-performance RF receiver with an on-board
decoder. When paired with a matching KH2
RF RECEIVER/DECODER
0.630"
Series transmitter / encoder module, OEM
RXD-418-KH2
transmitter, or LC or LR Series transmitter and
LOT 1000
Holtek HT640 encoder combination, a highly
reliable wireless link is formed that is capable of
transferring the status of eight parallel inputs for 0.180"
distances of up to 3000 feet. Ten tri-state
address lines provide 59,049 (310) different
addresses for security and uniqueness. Housed
Figure 1: Package Dimensions
in a compact SMD package, the KH2 module
utilizes an advanced synthesized architecture to achieve an unmatched blend of
performance, size, range and cost. No external RF components are required except
an antenna, making design integration straightforward.
FEATURES
n
n
n
n
n
Low cost
Long range
On-board decoder
8 parallel binary outputs
310 addresses for security and
uniqueness
n Ultra-low power consumption
n Compact SMD package
n Advanced synthesized
architecture
n Received data output
n Transmission validation
n No production tuning
n No external RF components
required (except an antenna)
n Pin-compatible with original KH
APPLICATIONS INCLUDE
ORDERING INFORMATION
n
n
n
n
n
n
n
n
n
PART #
DESCRIPTION
TXE-315-KH2
Transmitter / Encoder 315MHz
TXE-418-KH2
Transmitter / Encoder 418MHz
TXE-433-KH2
Transmitter / Encoder 433MHz
RXD-315-KH2
Receiver / Decoder 315MHz
RXD-418-KH2
Receiver / Decoder 418MHz
RXD-433-KH2
Receiver / Decoder 433MHz
EVAL-***-KH2
Basic Evaluation Kit
*** = Frequency
Receivers are supplied in tubes of 20 pcs.
Remote Control / Command
Keyless Entry
Garage / Gate Openers
Lighting Control
Call Systems
Home / Industrial Automation
Fire / Security Alarms
Remote Status Monitoring
Wire Elimination
Revised 7/21/11
ELECTRICAL SPECIFICATIONS
Parameter
POWER SUPPLY
Operating Voltage
With Dropping Resistor
Supply Current
Power-Down Current
RECEIVER SECTION
Receive Frequency Range:
RXD-315-KH2
RXD-418-KH2
RXD-433-KH2
Center Frequency Accuracy
LO Feedthrough
IF Frequency
Noise Bandwidth
Data Rate
Data Output:
Logic Low
Logic High
Power-Down Input:
Logic Low
Logic High
Receiver Sensitivity
RSSI / Analog:
Dynamic Range
Analog Bandwidth
Gain
Voltage With No Carrier
ANTENNA PORT
RF Input Impedance
TIMING
Receiver Turn-On Time:
Via VCC
Via PDN
Max. Time Between Transitions
ABSOLUTE MAXIMUM RATINGS
Designation
Min.
Typical
Max.
Units
Notes
VCC
2.7
4.3
4.0
20.0
3.0
5.0
5.2
28.0
3.6
5.2
7.0
35.0
VDC
VDC
mA
µA
–
1,5
–
5
–
–
–
-50
–
–
–
100
315
418
433.92
–
-80
10.7
280
–
–
–
–
+50
–
–
–
10,000
MHz
MHz
MHz
kHz
dBm
MHz
kHz
bps
–
–
–
–
2,5
5
–
–
ICC
IPDN
Supply Voltage VCC
Supply Voltage VCC, Using Resistor
Any Input or Output Pin
RF Input
Operating Temperature
Storage Temperature
Soldering Temperature
FC
–
–
FIF
N3DB
–
VOL
VOH
–
–
VIL
VIH
–
–
VCC-0.4
-106
–
–
-112
0.4
–
-118
VDC
VDC
dBm
–
–
4
–
–
–
–
–
50
–
–
80
–
16
1.5
–
5,000
–
–
dB
Hz
mV / dB
V
5
5
5
5
RIN
–
50
–
Ω
5
–
–
–
3.0
0.04
–
7.0
0.25
10.0
10.0
0.50
–
mSec
mSec
mSec
5,6
5,6
5
–
–
FENC
–
–
–
–
0.6
26 bits 3x
50%
70
1.0
–
–
–
1.2
–
–
kHz
mA
–
–
–
7
–
-40
–
+70
°C
5
0.0
3.0
–
–
VDC
VDC
These performance parameters
are based on module operation at
25°C from a 3.0VDC supply unless
otherwise
noted.
Figure
2
illustrates
the
connections
necessary
for
testing
and
operation. It is recommended all
ground pins be connected to the
ground plane. The pins marked NC
have no electrical connection and
are designed only to add physical
support.
5VDC
330Ω
External
Resistor
3VDC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
NC
D0
D1
GND
VCC
PDN
D2
D3
D4
DATA
VT
D5
D6
D7
ANT
GND
NC
RSSI
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Figure 2: Test / Basic Application Circuit
TYPICAL PERFORMANCE GRAPHS
PDN
Supply
RX Data
RX DATA
Figure 3: Turn-On Time from VCC
Table 1: KH2 Series Receiver Specifications
Figure 4: Turn-On Time from PDN
5.40
Notes
RFIN >-35dBm
Supply Current (mA)
5.35
5.30
5.25
With Dropping
Resistor
NO RFIN
5.20
5.15
5.10
2.7 2.8 2.9
3.0 3.1 3.2 3.3
3.4 3.5 3.6 3.7
3.8 3.9 4.0 4.1
4.2 4.3 4.4 4.5
4.6 4.7 4.8 4.9
5.0 5.1 5.2
Supply Voltage (VDC)
Figure 5: Consumption vs. Supply
Page 2
VDC
VDC
VDC
dBm
°C
°C
PERFORMANCE DATA
3
3
1. The KH2 can utilize a 4.3 to 5.2VDC supply provided a 330-ohm resistor is placed in series with VCC.
2. Into a 50-ohm load.
3. When operating from a 5V 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 requirement of the device to which data is being sent.
4. For BER of 10-5 at 1,200bps.
5. Characterized, but not tested.
6. Time to valid data output.
7. Maximum drive capability of data outputs.
to
+3.6
to
+5.2
to
+3.6
0
-30
to
+70
-45
to
+85
+225°C for 10 seconds
*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.
DECODER SECTION
TX Data Length
Average Data Duty Cycle
Decoder Oscillator
Output Drive Current
ENVIRONMENTAL
Operating Temperature Range
-0.3
-0.3
-0.3
Figure 6: RSSI Response Time
Page 3
PIN ASSIGNMENTS
MODULE DESCRIPTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
NC
D0
D1
GND
VCC
PDN
D2
D3
D4
DATA
VT
D5
D6
D7
ANT
GND
NC
RSSI
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
28
27
26
25
24
23
22
21
20
19
18
17
16
15
The KH2 Series module combines the popular Linx LR Series receiver with a
decoder IC in a convenient SMD package. The module is ideal for generalpurpose remote control and command applications. When paired with a
matching Linx KH2 Series transmitter / encoder, OEM transmitter, LC, or LR
Series transmitter and Holtek HT640 encoder combination, a highly reliable RF
link is formed, capable of transferring control and command data over line-ofsight distances in excess of 3,000 feet. The on-board receiver / decoder
combination provides eight switched outputs that correspond to the state of the
data lines on the transmitter’s encoder. Ten tri-state address lines are also
provided to allow up to 59,049 (310) unique identification codes.
RF Stage
50Ω RF IN
(Antenna)
Data Slicer
-
∑
PIN DESCRIPTIONS
Band Select
Filter
Pin #
Name
Description
1
NC
No Connection. For physical support only.
D0-D7
Data Output Lines. Upon a valid transmission, these lines
will be set to replicate the state of the transmitter’s data
lines.
4
GND
Analog Ground
5
VCC
Supply Voltage
PDN
Power Down. Pulling this line low will place the receiver into
a low-current state. The module will not be able to receive a
signal in this state.
Data Out
+
RSSI/Analog
Limiter
90˚
PLL
2, 3, 7, 8,
9, 12, 13,
14
10.7MHz
IF Filter
0˚
LNA
Figure 7: KH2 Series Receiver Pinout (Top View)
VCO
XTAL
Decoder Stage
Oscillator
Divider
Buffer
Data
Collector
8-bit
Shift
Register
Latch
Circuit
AND
Circuit
D0
D1
D2
D3
D4
D5
D6
D7
Buffer
6
10
DATA
Data output of the receiver prior to the encoder.
11
VT
Valid Transmission. This line will go high when a valid
transmission is received.
15-24
A0-A9
Address Lines. The state of these lines must match the
state of the transmitter’s address lines in order for a
transmission to be accepted.
25
RSSI
Received Signal Strength Indicator. This line will supply an
analog voltage that is proportional to the strength of the
received signal.
Sync.
Detector
Comparator
Comparator
Control
Logic
Transmission Gate Circuit
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9
26
NC
No Connection. For physical support only.
27
GND
Analog Ground
28
RF IN
50-ohm RF Input
Page 4
Figure 8: KH2 Series Receiver Block Diagram
THEORY OF OPERATION
The KH2 Series receiver module is designed to receive transmissions from a
matching KH2 Series transmitter module or other compatible Linx transmitter
product. When transmitted data is received, the data is presented to the onboard decoder. If the incoming address matches the local address settings, the
decoder’s outputs are set to replicate the states of the transmitter’s data lines.
The RF section of the KH2 module utilizes an advanced single-conversion
superhet design with a synthesized architecture, high IF frequency, and multilayer ceramic filters. The exceptional accuracy of the crystal-based synthesized
archetecture in the KH2 receiver module allows the receiver’s pass band to be
quite narrow, thus increasing sensitivity and reducing susceptibility to near-band
interference.
Page 5
DECODER OPERATION
THE DATA OUTPUTS
The KH2 Series receiver utilizes the HT658
decoder from Holtek. The decoder receives
data transmitted by the encoder and
interprets the first 10 bits of the code period
as address and the last 8 bits as data. A
signal on the DATA line activates the
oscillator, which in turn decodes the
incoming address and data. The decoder
will check the received address twice
continuously. If the received address code
matches the decoder’s local address, the 8
bits of data are replicated on the output
lines, and the VT line is set high to indicate
the reception of a valid transmission. That
will last until the address code is incorrect or
no signal has been received. The VT line is
high only when the transmission is valid,
otherwise it is low. The data outputs are
momentary, and follow the encoder during a
valid transmission, then reset.
Power On
Standby Mode
No
Disable VT &
Ignore the Rest of
This Word
Code In?
Yes
Address Bits
Matched?
In addition to the decoded data outputs, raw data is also available via a CMOScompatible data output (DATA, Pin 10). The output of this line is the actual
received data stream from the receiver and is always active regardless of
address line status. It is made available for troubleshooting or monitoring internal
data flow. It can also be used in mixed-mode systems where data may come
from another source in addition to a KH Series transmitter module. This data can
then be channeled to an external processor for decoding.
No
Yes
Store Data
Match
Previous Stored
Data?
No
Yes
No
RECEIVING DATA
2 Times
of Checking
Completed?
Although the internal decoder handles all of the decoding and output for
transmissions from a KH2 Series transmitter or an OEM transmitter, the KH2
Series receiver will output the raw received data on the DATA line. This allows
the designer to create a mixed system of KH2 Series or OEM transmitters for
encoded data as well as LC or LR Series transmitters for custom data.
Yes
Data to Output &
Activate VT
No
Address or
Data Error?
The oscillator is disabled in the standby
Yes
state and activated as long as a logic “high”
signal is applied to the DATA line, so the Figure 9: Decoder Flowchart
DATA line should be kept “low” if there is no signal input.
Encoder
Transmit
Enable
< 1 Word
Encoder
Data Out
3 Words
Transmitted Continuously
Decoder VT
214 Clocks
2 Words
Check
When using the KH2 for custom data transmissions, it is up to the designer to
implement a noise-tolerant protocol to ensure the integrity of the data.
Application Note AN-00160 will provide some suggestions and guidlines.
The KH2 Series receiver module contains the LR Series receiver, which has a
CMOS-compatible output capable of directly driving a microprocessor, an RS232 level converter, or a Linx QS Series USB module. The LR Series receiver
manual can be consulted for more details on the operation of the receiver itself.
POWER SUPPLY REQUIREMENTS
3 Words
214 Clocks
When data is received and the incoming address data matches with the local
address settings, the module’s eight data output lines are set to replicate the
state of the transmitter’s data lines. In addition, the valid transmission line (VT,
Pin 11) will go high to indicate reception and decoding of the data. The data lines
have a low sink and source capability, so external buffering is generally required
if loads are to be driven directly.
Check
Decoder
Data Out
The module does not have an internal voltage regulator; therefore it requires a
clean, well-regulated power source. While it is
Vcc TO
MODULE
preferable to power the unit from a battery, it can also
be operated from a power supply as long as noise is
10Ω
less than 20mV. Power supply noise can affect the Vcc IN
receiver sensitivity; therefore, providing a clean power
10μF
supply for the module should be a high priority during
design.
+
1/2 Clock Time
1/2 Clock Time
Figure 10: Encoder / Decoder Timing Diagram
SETTING THE RECEIVER ADDRESS
The module provides ten tri-state address lines. This allows for the formation of
up to 59,049 (310) unique receiver-transmitter relationships. Tri-state means that
the address lines can be set to one of three distinct states: high, low, or floating.
These lines may be hardwired or configured via a microprocessor, DIP switch,
or jumpers.
A 10Ω resistor in series with the supply followed by a
Figure 11: Supply Filter
10µF tantalum capacitor from VCC to ground will help
in cases where the quality of supply power is poor. These values may need to
be adjusted depending on the noise present on the supply line. Note that
operation from 4.3 to 5.2 volts requires the use of an external 330Ω resistor
placed in series with the supply to prevent VCC from exceeding 3.6 volts, so the
dropping resistor can take the place of the 10Ω resistor in the supply filter.
The receiver’s address line states must match the transmitter’s exactly for a
transmission to be recognized. If the transmitted address does not match the
receiver’s local address, then the receiver will take no action.
Page 6
Page 7
USING THE RSSI PIN
TYPICAL APPLICATIONS
The receiver’s Received Signal Strength Indicator (RSSI) line serves a variety of
functions. This line has a dynamic range of 80dB (typical) and outputs a voltage
proportional to the incoming signal strength. It should be noted that the RSSI
levels and dynamic range will vary slightly from part to part. It is also important
to remember that RSSI output indicates the strength of any in-band RF energy
and not necessarily just that from the intended transmitter; therefore, it should be
used only to qualify the level and presence of a signal.
The RSSI output can be utilized during testing or even as a product feature to
assess interference and channel quality by looking at the RSSI level with all
intended transmitters shut off. The RSSI output can also be used in directionfinding applications, although there are many potential perils to consider in such
systems. Finally, it can be used to save system power by “waking up” external
circuitry when a transmission is received or crosses a certain threshold. The
RSSI output feature adds tremendous versatility for the creative designer.
The figure below shows an example of a basic remote control receiver utilizing
the KH2 Series receiver module. When a key is pressed on the transmitter, a
corresponding line on the receiver goes high. A schematic for the transmitter /
encoder circuit may be found in the KH2 Series Transmitter Data Guide. These
circuits are implemented in the KH2 Series Basic Evaluation Kit. They can be
easily modified for a custom application and clearly demonstrate the ease of
using the Linx KH2 Series modules for remote control applications.
VCC
VCC
BZ1
BUZZER
S4
Q1
2N2222
R2
2.2k
ANT1
1
R4
10k
INTERFERENCE CONSIDERATIONS
2
VCC
3
VCC
GND
The RF spectrum is crowded and the potential for conflict with other unwanted
sources of RF is very real. While all RF products are at risk from interference, its
effects can be minimized by better understanding its characteristics.
Interference may come from internal or external sources. The first step is to
eliminate interference from noise sources on the board. This means paying
careful attention to layout, grounding, filtering, and bypassing in order to
eliminate all radiated and conducted interference paths. For many products, this
is straightforward; however, products containing components such as switching
power supplies, motors, crystals, and other potential sources of noise must be
approached with care. Comparing your own design with a Linx evaluation board
can help to determine if and at what level design-specific interference is present.
External interference can manifest itself in a variety of ways. Low-level
interference will produce noise and hashing on the output and reduce the link’s
overall range.
High-level interference is caused by nearby products sharing the same
frequency or from near-band high-power devices. It can even come from your
own products if more than one transmitter is active in the same area. It is
important to remember that only one transmitter at a time can occupy a
frequency, regardless of the coding of the transmitted signal. This type of
interference is less common than those mentioned previously, but in severe
cases it can prevent all useful function of the affected device.
Although technically it is not interference, multipath is also a factor to be
understood. Multipath is a term used to refer to the signal cancellation effects
that occur when RF waves arrive at the receiver in different phase relationships.
This effect is a particularly significant factor in interior environments where
objects provide many different signal reflection paths. Multipath cancellation
results in lowered signal levels at the receiver and, thus, shorter useful distances
for the link.
LED1
RED LED
4
GND
5
6
7
R6
220 OHM
Q2
2N2222
8
R3
2.2k
9
10
11
12
R5
10k
13
14
GND
NC
ANT
D0
GND
D1
NC
GND
RSSI
VCC
A9
PDN
A8
D2
A7
D3
A6
D4
A5
DATA
A4
VT
A3
D5
A2
D6
A1
D7
A0
27
GND
26
25
GND
S1
24
23
22
21
20
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
19
SW-DIP-10
18
17
GND
16
15
RXD-XXX-KH2
Figure 12: Basic Remote Control Receiver
The ten-position DIP switch is used to set the address to either ground or
floating. Since the floating state is a valid state, no pull-up resistors are needed.
The data line outputs can only source about 1mA of current, so transistor buffers
are used to drive the buzzer and LED. 1mA is sufficient to activate most
microcontrollers, but the manufacturer’s data guides should be consulted to
make sure.
The KH2 Series receiver / decoder module is also suitable for use with Linx OEM
handheld transmitters. These transmitters are FCC certified, making product
introduction extremely quick. Information on these transmitters can be found on
the Linx website at www.linxtechnologies.com.
Figure 13: Linx OEM Transmitters
Page 8
B1
CR2032 3V LITHIUM
28
Figure 14: Linx OEM Keyfobs
Page 9
BOARD LAYOUT GUIDELINES
MICROSTRIP DETAILS
If you are at all familiar with RF devices, you may be concerned about
specialized board layout requirements. Fortunately, because of the care taken by
Linx in designing the modules, integrating them is very straightforward. Despite
this ease of application, it is still necessary to maintain respect for the RF stage
and exercise appropriate care in layout and application in order to maximize
performance and ensure reliable operation. The antenna can also be influenced
by layout choices. Please review this data guide in its entirety prior to beginning
your design. By adhering to good layout principles and observing some basic
design rules, you will be on the path to RF success.
The adjacent figure shows the suggested
PCB footprint for the module. The actual pad
dimensions are shown in the Pad Layout
section of this manual. A ground plane (as
large as possible) should be placed on a
lower layer of your PC board opposite the
module. This ground plane can also be critical
to the performance of your antenna, which will
be discussed later. There should not be any
ground or traces under the module on the
same layer as the module, just bare PCB.
GROUND PLANE
ON LOWER LAYER
A transmission line is a medium whereby RF energy is transferred from one
place to another with minimal loss. This is a critical factor, especially in highfrequency products like Linx RF modules, because the trace leading to the
module’s antenna can effectively contribute to the length of the antenna,
changing its resonant bandwidth. In order to minimize loss and detuning, some
form of transmission line between the antenna and the module should be used,
unless the antenna can be placed very close ( the overall length of the 1/4-wave
PLANE
VIRTUAL λ/4
radiating element. This is often not practical due to
DIPOLE
size and configuration constraints. In these
instances, a designer must make the best use of the Figure 23: Dipole Antenna
area available to create as much ground plane as
possible in proximity to the base of the antenna. In cases where the antenna is
remotely located or the antenna is not in close proximity to a circuit board,
ground plane, or grounded metal case, a metal plate may be used to maximize
the antenna’s performance.
E
λ/4
I
λ/4
5. Remove the antenna as far as possible from potential interference sources. Any
frequency of sufficient amplitude to enter the receiver’s front end will reduce
system range and can even prevent reception entirely. Switching power
supplies, oscillators, or even relays can also be significant sources of potential
interference. The single best weapon against such problems is attention to
placement and layout. Filter the module’s power supply with a high-frequency
bypass capacitor. Place adequate ground plane under potential sources of noise
to shunt noise to ground and prevent it from coupling to the RF stage. Shield
noisy board areas whenever practical.
6. In some applications, it is advantageous to
place the module and antenna away from the
main equipment. This can avoid interference
problems and allows the antenna to be
oriented for optimum performance. Always use
50Ω coax, like RG-174, for the remote feed.
CASE
NUT
GROUND PLANE
(MAY BE NEEDED)
Figure 24: Remote Ground Plane
Page 15
COMMON ANTENNA STYLES
ONLINE RESOURCES
There are literally hundreds of antenna styles and variations that can be
employed with Linx RF modules. Following is a brief discussion of the styles
most commonly utilized. Additional antenna information can be found in Linx
Application Notes AN-00100, AN-00140, and AN-00500. Linx antennas and
connectors offer outstanding performance at a low price.
Whip Style
L=
A whip-style antenna provides outstanding overall performance
and stability. A low-cost whip is can be easily fabricated from a
wire or rod, but most designers opt for the consistent
performance and cosmetic appeal of a professionally-made
model. To meet this need, Linx offers a wide variety of straight
and reduced-height whip-style antennas in permanent and
connectorized mounting styles.
234
F MHz
Where:
L = length in feet of
quarter-wave length
F = operating frequency
in megahertz
The wavelength of the operational frequency determines an
antenna’s overall length. Since a full wavelength is often quite
long, a partial 1/2- or 1/4-wave antenna is normally employed.
Its size and natural radiation resistance make it well matched to
Linx modules. The proper length for a straight 1/4-wave can be
easily determined using the adjacent formula. It is also possible
to reduce the overall height of the antenna by using a helical
winding. This reduces the antenna’s bandwidth, but is a great
way to minimize the antenna’s physical size for compact
applications. This also means that the physical appearance is
not always an indicator of the antenna’s frequency.
Specialty Styles
Loop Style
Linx offers a wide variety of specialized antenna styles.
Many of these styles utilize helical elements to reduce the
overall antenna size while maintaining reasonable
performance. A helical antenna’s bandwidth is often quite
narrow and the antenna can detune in proximity to other
objects, so care must be exercised in layout and placement.
A loop- or trace-style antenna is normally printed directly on a
product’s PCB. This makes it the most cost-effective of antenna
styles. The element can be made self-resonant or externally
resonated with discrete components, but its actual layout is
usually product specific. Despite the cost advantages, loop-style
antennas are generally inefficient and useful only for short-range
applications. They are also very sensitive to changes in layout and
PCB dielectric, which can cause consistency issues during
production. In addition, printed styles are difficult to engineer,
requiring the use of expensive equipment, including a network
analyzer. An improperly designed loop will have a high SWR at the
desired frequency, which can cause instability in the RF stage.
Linx offers low-cost planar and chip antennas that mount directly
to a product’s PCB. These tiny antennas do not require testing and
provide excellent performance in light of their small size. They
offer a preferable alternative to the often-problematic “printed”
antenna.
Page 16
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Software Updates
If you have questions regarding any Linx product and have Internet access,
make www.linxtechnologies.com your first stop. Our website is organized in an
intuitive format to immediately give you the answers you need. Day or night, the
Linx website gives you instant access to the latest information regarding the
products and services of Linx. It’s all here: manual and software updates,
application notes, a comprehensive knowledgebase, FCC information, and much
more. Be sure to visit often!
www.antennafactor.com
The Antenna Factor division of Linx offers
a diverse array of antenna styles, many of
which are optimized for use with our RF
modules. From innovative embeddable
antennas to low-cost whips, domes to
Yagis, and even GPS, Antenna Factor
likely has an antenna for you, or can
design one to meet your requirements.
www.apexwireless.com
Apex Wireless provides contract engineering services,
specializing in small, low-cost RF transmitters and
receivers that operate in the unlicensed bands. Their
designs include data links, tracking systems, remote
controls, RFID and resource management systems.
Page 17
LEGAL CONSIDERATIONS
NOTE: Linx RF modules are designed as component devices that require
external components to function. The modules are intended to allow for full Part
15 compliance; however, they are not approved by the FCC or any other agency
worldwide. The purchaser understands that approvals may be required prior to
the sale or operation of the device, and agrees to utilize the component in keeping
with all laws governing its use in the country of operation.
When working with RF, a clear distinction must be made between what is technically
possible and what is legally acceptable in the country where operation is intended. Many
manufacturers have avoided incorporating RF into their products as a result of
uncertainty and even fear of the approval and certification process. Here at Linx, our
desire is not only to expedite the design process, but also to assist you in achieving a
clear idea of what is involved in obtaining the necessary approvals to legally market your
completed product.
In the United States, the approval process is actually quite straightforward. The
regulations governing RF devices and the enforcement of them are the responsibility of
the Federal Communications Commission (FCC). The regulations are contained in Title
47 of the Code of Federal Regulations (CFR). Title 47 is made up of numerous volumes;
however, all regulations applicable to this module are contained in Volume 0-19. It is
strongly recommended that a copy be obtained from the Government Printing Office in
Washington or from your local government bookstore. Excerpts of applicable sections are
included with Linx evaluation kits or may be obtained from the Linx Technologies website,
www.linxtechnologies.com. In brief, these rules require that any device that intentionally
radiates RF energy be approved, that is, tested for compliance and issued a unique
identification number. This is a relatively painless process. Linx offers full EMC precompliance testing in our HP / Emco-equipped test center. Final compliance testing is
then performed by one of the many independent testing laboratories across the country.
Many labs can also provide other certifications that the product may require at the same
time, such as UL, CLASS A / B, etc. Once your completed product has passed, you will
be issued an ID number that is to be clearly placed on each product manufactured.
Questions regarding interpretations of the Part 2 and Part 15 rules or measurement
procedures used to test intentional radiators, such as Linx RF modules, for compliance
with the technical standards of Part 15, should be addressed to:
Federal Communications Commission
Equipment Authorization Division
Customer Service Branch, MS 1300F2
7435 Oakland Mills Road
Columbia, MD 21046
Phone: (301) 725-1585 Fax: (301) 344-2050 E-Mail: labinfo@fcc.gov
International approvals are slightly more complex, although Linx modules are designed
to allow all international standards to be met. If you are considering the export of your
product abroad, you should contact Linx Technologies to determine the specific suitability
of the module to your application.
All Linx modules are designed with the approval process in mind and thus much of the
frustration that is typically experienced with a discrete design is eliminated. Approval is
still dependent on many factors, such as the choice of antennas, correct use of the
frequency selected, and physical packaging. While some extra cost and design effort are
required to address these issues, the additional usefulness and profitability added to a
product by RF makes the effort more than worthwhile.
Page 18
ACHIEVING A SUCCESSFUL RF IMPLEMENTATION
Adding an RF stage brings an exciting new
dimension to any product. It also means that
additional effort and commitment will be needed to
bring the product successfully to market. By utilizing
premade RF modules, such as the LR Series, the
design and approval process is greatly simplified. It
is still important, however, to have an objective view
of the steps necessary to ensure a successful RF
integration. Since the capabilities of each customer
vary widely, it is difficult to recommend one
particular design path, but most projects follow steps
similar to those shown at the right.
DECIDE TO UTILIZE RF
RESEARCH RF OPTIONS
ORDER EVALUATION KIT(S)
TEST MODULE(S) WITH
BASIC HOOKUP
CHOOSE LINX MODULE
INTERFACE TO CHOSEN
CIRCUIT AND DEBUG
CONSULT LINX REGARDING
ANTENNA OPTIONS AND DESIGN
LAY OUT BOARD
In reviewing this sample design path, you may
SEND PRODUCTION-READY
PROTOTYPE TO LINX
FOR EMC PRESCREENING
notice that Linx offers a variety of services (such as
antenna design and FCC prequalification) that are
OPTIMIZE USING RF SUMMARY
GENERATED BY LINX
unusual for a high-volume component manufacturer.
SEND TO PART 15
These services, along with an exceptional level of
TEST FACILITY
technical support, are offered because we recognize
RECEIVE FCC ID #
that RF is a complex science requiring the highest
caliber of products and support. “Wireless Made
COMMENCE SELLING PRODUCT
Simple” is more than just a motto, it’s our
Typical Steps For
commitment. By choosing Linx as your RF partner
Implementing RF
and taking advantage of the resources we offer, you
will not only survive implementing RF, you may even find the process enjoyable.
HELPFUL APPLICATION NOTES FROM LINX
It is not the intention of this manual to address in depth many of the issues that
should be considered to ensure that the modules function correctly and deliver
the maximum possible performance. As you proceed with your design, you may
wish to obtain one or more of the following application notes, which address in
depth key areas of RF design and application of Linx products. These
applications notes are available online at www.linxtechnologies.com or by
contacting the Linx literature department.
NOTE
APPLICATION NOTE TITLE
AN-00100
RF 101: Information for the RF Challenged
AN-00125
Considerations For Operation Within The 260-470MHz Band
AN-00130
Modulation Techniques For Low-Cost RF Data Links
AN-00140
The FCC Road: Part 15 From Concept To Approval
AN-00150
Use and Design of T-Attenuation Pads
AN-00160
Considerations For Sending Data Over a Wireless Link
AN-00300
Addressing Linx OEM Products
AN-00500
Antennas: Design, Application, Performance
Page 19
WIRELESS MADE SIMPLE ®
U.S. CORPORATE HEADQUARTERS
LINX TECHNOLOGIES
159 ORT LANE
MERLIN, OR 97532
PHONE: (541) 471-6256
FAX: (541) 471-6251
www.linxtechnologies.com
Disclaimer
Linx Technologies is continually striving to improve the quality and function of its products. For this reason,
we reserve the right to make changes to our products without notice. The information contained in this
Overview Guide is believed to be accurate as of the time of publication. Specifications are based on
representative lot samples. Values may vary from lot-to-lot and are not guaranteed. "Typical" parameters can
and do vary over lots and application. Linx Technologies makes no guarantee, warranty, or representation
regarding the suitability of any product for use in any specific application. It is the customer's responsibility
to verify the suitability of the part for the intended application. NO LINX PRODUCT IS INTENDED FOR USE
IN ANY APPLICATION WHERE THE SAFETY OF LIFE OR PROPERTY IS AT RISK.
Linx Technologies DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE. IN NO EVENT SHALL LINX TECHNOLOGIES BE LIABLE FOR ANY OF
CUSTOMER'S INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY FROM ANY DEFECTIVE
OR NON-CONFORMING PRODUCTS OR FOR ANY OTHER BREACH OF CONTRACT BY LINX
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adjustments, costs, and expenses incurred by Linx Technologies as a result of or arising from any Products
sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for
losses arising from the use or failure of the device in any application, other than the repair, replacement, or
refund limited to the original product purchase price. Devices described in this publication may contain
proprietary, patented, or copyrighted techniques, components, or materials. Under no circumstances shall
any user be conveyed any license or right to the use or ownership of such items.
© 2011 by Linx Technologies. The stylized Linx logo, Linx,
“Wireless Made Simple”, CipherLinx, and the stylized CL
logo are the trademarks of Linx Technologies.
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