HIGH-PERFORMANCE
RF MODULE
RXM-900-HP3-xxx
WIRELESS MADE SIMPLE ®
HP3 SERIES RECEIVER MODULE DATA GUIDE
DESCRIPTION
1.940"
The HP3 RF receiver module offers complete
HP SERIES RF RECEIVER
compatibility and numerous enhancements
0.780"
RXM-900-HP3-SP*
over previous generations. The HP3 is
designed for the cost-effective, highperformance wireless transfer of analog or
0.236"
digital information in the popular 902-928MHz
SIP Style
band. All HP3 Series modules feature eight
1.950"
parallel selectable channels, but versions are
HP SERIES RF RECEIVER
also available which add serial selection of 100
0.750"
RXM-900-HP3-SP*
channels. To ensure reliable performance, the
receiver employs FM / FSK demodulation and
0.190"
an advanced dual-conversion microprocessorSMD Style
controlled synthesized architecture. The
Figure 1: Package Dimensions
receiver is pin- and footprint-compatible with all
previous generations, but its overall physical size has been reduced. Both SMD and
pinned packages are available. When paired with an HP3 transmitter, a reliable link
is created for transferring analog and digital information up to 1,000 feet. (under
optimal conditions). As with all Linx modules, the HP3 requires no tuning or additional
RF components (except an antenna), making integration straightforward even for
engineers without prior RF experience.
LOT 10000
Pin Spacing: 0.1"
LOT 10000
FEATURES
APPLICATIONS INCLUDE
Wireless Networks / Data Transfer
8 parallel / 100 serial (PS Versions)
Wireless Analog / Audio
user-selectable channels
Home / Industrial Automation
FM / FSK demodulation for outstanding
Remote Access / Control
performance and noise immunity
Exceptional sensitivity (-100dBm typical) Remote Monitoring / Telemetry
Long-Range RFID
Wide-range analog capability including
MIDI Links
audio (50Hz to 28kHz)
Voice / Music / Intercom Links
RSSI and Power-down lines
Precision frequency
ORDERING INFORMATION
synthesized architecture
PART #
DESCRIPTION
No external RF
components required
RXM-900-HP3-PPO
HP3 Receiver (SIP 8 CH only)
Compatible with previous RXM-900-HP3-PPS
HP3 Receiver (SIP 8p / 100s CH)
HP Series modules
RXM-900-HP3-SPO
HP3 Receiver (SMD 8 CH only)
High data rate
RXM-900-HP3-SPS
HP3
Receiver (SMD 8p / 100s CH)
(up to 56kbps)
MDEV-900-HP3-PPS-USB
HP3 Development Kit (Pinned Pkg.)
Wide supply range
(2.8 to 13.0VDC)
MDEV-900-HP3-PPS-RS232
HP3 Development Kit (Pinned Pkg.)
Direct serial interface
MDEV-900-HP3-SPS-USB
HP3 Development Kit (SMD Pkg.)
Pinned and SMD packages MDEV-900-HP3-SPS-RS232 HP3 Development Kit (SMD Pkg.)
Wide temperature range
Receivers are supplied in tubes of 10 pcs.
(-30°C to +85°C)
Revised 1/28/08
ELECTRICAL SPECIFICATIONS
Parameter
Designation
Min.
ABSOLUTE MAXIMUM RATINGS
Typical
Max.
Units
Notes
–
Supply Voltage VCC
Any Input or Output Pin
Operating Temperature
Storage Temperature
Soldering Temperature
POWER SUPPLY
Operating Voltage
VCC
2.8
3.0
13.0
VDC
Supply Current
ICC
16.0
19.0
21.0
mA
1
Power-Down Current
IPDN
–
5.6
10.0
µA
2
FC
902.62
–
927.62
MHz
3
RECEIVE SECTION
Receive Frequency Range
Center Frequency Accuracy
+50
kHz
–
250
–
kHz
3
First IF Frequency
–
34.7
–
MHz
4
Second IF Frequency
–
10.7
–
MHz
4
Channel Spacing
Noise Bandwidth
-50
–
N3DB
–
280
–
kHz
–
Data Rate
–
100
–
56,000
bps
–
Analog / Audio Bandwidth
–
50
–
28,000
Hz
4
0.8
1.1
2.0
VAC
5
Analog / Audio Output Level
–
0.0
–
0.5
VDC
6
Logic High
–
VCC-0.3
–
VCC
VDC
6
Output Impedance
–
17
–
kohms
–
Data Output Source Current
–
230
–
µA
7
-94
-100
-107
dBm
8,9
Receiver Sensitivity
to
+18.0
to
VCC
to
+85
to
+85
for 10 seconds
PERFORMANCE DATA
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.
PC
PC
PC
5VDC
PC
RSSI:
Dynamic Range
60
70
80
dB
4
Gain
–
24
–
mV/dB
4
Voltage With No Carrier
Spurious Emissions
–
–
1.6
V
4
–
-57
–
dBm
4
–
–
54
57
–
–
dB
dB
4
4
VDC
VDC
°C
°C
*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.
Data Output:
Logic Low
-0.3
-0.3
-30
-45
+260°C
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
ANT
GND
GND
GND
GND
GND
GND
GND
NC
CS0
CS1 / SS CLOCK
CS2 / SS DATA
PDN
RSSI
MODE
VCC
AUDIO
DATA
Figure 2: Test / Basic Application Circuit
TYPICAL PERFORMANCE GRAPHS
Interference Rejection:
RF Input Impedance
ROUT
–
50
–
Ω
3.0
PDN
4
1
TIMING
RX DATA
Receiver Turn-On Time:
via VCC
T4
–
–
7.0
mSec
4
via PDN
T3
–
–
3.0
mSec
4
Channel Change Time
T2
–
–
1.5
mSec
4
Max time between transitions
T1
–
–
20
mSec
4
–
-30
–
+85
°C
4
ENVIRONMENTAL
Operating Temperature Range
RSSI VOLTAGE (V)
FC±1MHz
FC±5MHz
ANTENNA PORT
2.5
2.0
1.5
1.0
-110
2
CH1 1.00V
CH2 2.00V
500uS
-100
-90
Figure 3: RX Enabled to Valid Data
-80
-70
-60
-50
-40
RF INPUT (dBm)
Delta 1.920mS
Figure 4: Receiver RSSI
10-6
Table 1: HP3 Series Receiver Specifications
BER
RX ON >-35dBm
1. Over the entire operating voltage range.
2. With the PDN pin low.
3. Serial mode.
4. Characterized, but not tested.
5. With 1kHz sine wave @ 115kHz transmitter deviation
6. No load.
7. With 1V output drop.
8. For 10-5 @ 9,600bps.
9. At specified center frequency.
Page 2
10-5
RX OFF
Notes
10-4
10-3
-92 -93 -94
1
CH1 500mV
1mS
Delta 4.080mS
Figure 5: Worst Case RSSI Response Time
-95
-96 -97 -98
PIN (dBm)
-99
-100 -101 -102
Figure 6: BER vs. Input Power (typical)
Page 3
PIN ASSIGNMENTS
PIN DESCRIPTIONS
18 DATA
16 VCC
17 AUDIO
Surface-Mount Receiver
14 RSSI
15 MODE
12 CS2 / SS DATA
13 PDN
9 N/C
10 CS0
11 CS1 / SS CLOCK
7 GND
8 GND
5 GND
6 GND
3 GND
4 GND
1 ANT
2 GND
Pinned Receiver
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
ANT
GND
GND
GND
GND
GND
GND
GND
NC
CS0
CS1 / SS CLOCK
CS2 / SS DATA
PDN
RSSI
MODE
VCC
AUDIO
DATA
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
Pin #
Name
Equivalent Circuit
Description
1
ANT
2-8
GND
Analog Ground
9
NC
No Connection
10
CS0
RF In
50Ω
25k
12
CS1 /
SS CLOCK
CS2 /
SS DATA
Figure 7: HP3 Series Receiver Pinout
Channel Select 0
µ
CS0
11
50-ohm RF Input
25k
µ
CS1
25k
µ
CS2
Channel Select 1 /
Serial Select Clock
Channel Select 2 /
Serial Select Data
VCC
Pin #
Name
Description
1
ANT
50-ohm RF Input
2-8
GND
Analog Ground
9
NC
No Connection
10
CS0
Channel Select 0
11
CS1 / SS
CLOCK
12
CS2 / SS
DATA
13
PDN
14
RSSI
15
MODE
Channel Select 1 / Serial Select Clock. Channel Select 1
when in parallel channel selection mode, clock input for
serial channel selection mode.
Channel Select 1 / Serial Select Data. Channel Select 2
when in parallel channel selection mode, data input for
serial channel selection mode.
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.
Received Signal Strength Indicator. This line will supply an
analog voltage that is proportional to the strength of the
received signal.
PDN
VCC
Supply Voltage
17
AUDIO
Recovered Analog Output
18
DATA
Digital Data Output. This line will output the demodulated
digital data.
19-36
NC
No Connection (SMD only)
Power Down
(Active Low)
PDN
RSSI
14
RSSI
15
MODE
Received Signal
Strength Indicator
25k
Mode Select
µ
16
VCC
17
AUDIO
Mode Select. GND for parallel channel selection, VCC for
serial channel selection
16
Page 4
470k
13
Voltage Input 2.8-13V
VCC
1VP-P Analog Output
4.7k
18
DATA
19-36
NC
Digital Data Output
SMD Only
No Connection
Figure 8: Pin Functions and Equivalent Circuits
Page 5
POWER-UP SEQUENCE
The HP3 is a high-performance multi-channel, dual-conversion superhet
receiver capable of recovering both analog (FM) and digital (FSK) information
from a matching HP Series transmitter. FM / FSK modulation offers significant
advantages over AM or OOK modulation methods, including increased noise
immunity and the receiver’s ability to capture in the presence of multiple signals.
This is especially helpful in crowded bands, like that in which the HP3 operates.
Channel
Select
MODE
CS0
CS1
CS2
{
PLL
4MHz
Int. Osc.
24MHz
Crystal
RSSI
10.7MHz
BPF
Digital
Data
VCO
Quad
SAW BPF
34.7M
BPF
Analog
Data
IF
Amp
As previously mentioned, the HP3 is controlled
by an on-board microprocessor. When power
is applied, the microprocessor executes the
receiver start-up sequence, after which the
receiver is ready to receive valid data.
The adjacent figure shows the start-up
sequence. This sequence is executed when
power is applied to the VCC line or when the
PDN line is taken high.
On power-up, the microprocessor reads the
external channel selection lines and sets the
frequency synthesizer to the appropriate
channel. Once the frequency synthesizer has
stabilized, the receiver is ready to accept data.
LNA
10.7M
BPF
Limiter
10.7M
Discriminator
Figure 9: HP3 Series Receiver Block Diagram
The single-ended RF port is matched to 50-ohms to support commonly available
antennas, such as those manufactured by Linx. The RF signal coming in from
the antenna is filtered by a Surface Acoustic Wave (SAW) filter to attenuate
unwanted RF energy. A SAW filter provides significantly higher performance
than other filter types, such as an LC bandpass filter.
Once filtered, the signal is amplified by a Low Noise Amplifier (LNA) to increase
the receiver sensitivity and lower the overall noise figure of the receiver. After the
LNA, the signal is mixed with a synthesized local oscillator operating 34.7MHz
below the incoming transmission frequency to produce the first Intermediate
Frequency (IF).
The second conversion and FM demodulation is achieved by a highperformance IF strip that mixes the 34.7MHz first conversion frequency with
24.0MHz from a precision crystal oscillator. The resulting second IF of 10.7MHz
is then highly amplified in preparation for demodulation.
A quadrature demodulator is used to recover the baseband signal from the
carrier. The demodulated waveform is filtered, after which it closely resembles
the original signal. The signal is routed to the analog output pin and the data
slicer stage, which provides squared digital output via the data output pin. A key
feature of the HP3 is the transparency of its digital output, which does not impose
balancing or duty-cycle requirements within a range of 100bps to 56kbps.
An on-board microcontroller manages receiver functions and greatly simplifies
user interface. The microcontroller reads the channel selection lines and
programs the on-board synthesizer. This frees the designer from complex
programming requirements and allows for manual or software channel selection.
The microcontroller also monitors incoming signal strength and squelches the
data output when the signal is not strong enough for accurate data detection.
Page 6
POWER ON
Squelch Data
Output Pin
Parallel Mode
Serial Mode
Determine Mode
Read Channel
Selection Inputs
Program Freq. Synth
To Default CH. 50
Program Frequency
Synthesizer
Crystal Oscillator
Begins to Operate
Crystal Oscillator
Begins to Work
Ready for
Serial Data Input
Determine Squelch
State Data Output Pin
Determine Squelch
State Data Output Pin
Cycle Here Until
Channel
or Mode Change
Cycle Here Until More
Data Input
or Mode Change
Figure 10: Start-Up Sequence
POWER SUPPLY
The HP3 incorporates a precision, low-dropout
regulator on-board, which allows operation over an
input voltage range of 2.8 to 13 volts DC. Despite this
regulator, it is still important to provide a supply that
is free of noise. Power supply noise can significantly
affect the receiver sensitivity; therefore, providing a
clean power supply for the module should be a high
priority during design.
Vcc TO
MODULE
10Ω
Vcc IN
+
THEORY OF OPERATION
10μF
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. This filter should be placed close to the module’s supply
lines. These values may need to be adjusted depending on the noise present on
the supply line.
USING THE PDN PIN
The Power Down (PDN) line can be used to power down the receiver without the
need for an external switch. This line has an internal pull-up, so when it is held
high or simply left floating, the module will be active.
When the PDN line is pulled to ground, the receiver will enter into a low-current
(<10µA) power-down mode. During this time the receiver is off and cannot
perform any function. It may be useful to note that the startup time coming out
of power-down will be slightly less than when applying VCC.
The PDN line allows easy control of the receiver state from external
components, like a microcontroller. By periodically activating the receiver,
checking for data, then powering down, the receiver’s average current
consumption can be greatly reduced, saving power in battery-operated
applications.
Page 7
THE DATA OUTPUT
TIMING CONSIDERATIONS
The DATA line outputs recovered digital data. It is an open collector output with
an internal 4.7kΩ pull-up. When an RF transmission is not present, or when the
received signal strength is too low to ensure proper demodulation, the data
output is squelched continuous high. This feature supports direct operation with
UARTs, which require their input to be continuously high. An HP3 transmitter and
receiver can be directly connected between two UARTs without the need for
buffering or logical inversion. It should be noted that the squelch level is set just
over the receiver’s internal noise threshold. Any external RF activity above that
threshold will “break squelch” and produce hashing on the line. While the DATA
line will be reliably squelched in low-noise environments, the designer should
always plan for the potential of hashing.
AUDIO OUTPUT
The HP3 Series is optimized for the transmission of serial data; however, it can
also be used very effectively to send a variety of analog signals, including audio.
The ability of the HP3 to send combinations of audio and data opens new areas
of opportunity for creative design.
The analog output of the AUDIO line is valid from 50 Hz to 28 kHz, providing an
AC signal of about 1V peak-to-peak. This is a high impedance output and not
suitable for directly driving low-impedance loads, such as a speaker. In
applications where a low impedance load is to be driven, a buffer circuit should
always be used. For example, in the case of a speaker, a simple op-amp circuit
such as the one shown below can be used to act as an impedance converter.
VCC
1uF
HP Analog Out
10k
2
3
5
+
4
250uF
0.05uF
LM386
10 ohm
Figure 12: Audio Buffer Amplifier
The transmitter’s modulation voltage is critical, since it determines the carrier
deviation and distortion. The transmitter input level should be adjusted to
achieve the optimum results for your application in your circuit. Please refer to
the transmitter data guide for full details.
When used for audio, the analog output of the receiver should be filtered and
buffered to obtain maximum sound quality. For voice, a 3-4kHz low-pass filter is
often employed. For broader-range sources, such as music, a 12-17kHz cutoff
may be more appropriate. In applications that require high-quality audio, a
compandor may be used to further improve SNR. The HP3 is capable of
providing audio quality comparable to a radio or intercom. For applications where
true high fidelity audio is required, the HP3 will probably not be the best choice,
and a device optimized for audio should be utilized.
Page 8
Parameter
Description
Max.
T1
Time between DATA output transitions
20.0mS
T2
Channel change time (time to valid data)
1.5mS
T3
Receiver turn-on time via PDN
Receiver turn-on time via VCC
3.0mS
T4
7.0mS
T1 is the maximum amount of time that can elapse without a data transition. Data
must always be considered in both the analog and the digital domain. Because
the data stream is asynchronous and no particular format is imposed, it is
possible for the data to meet the receiver’s data rate requirement yet violate the
analog frequency requirements. For example, if a 255 (0FF hex) were sent
continuously, the receiver would view the data as a DC level. It would hold that
level until a transition was required to meet the minimum frequency specification.
If no transition occurred, data integrity could not be guaranteed. While no
particular structure or balancing requirement is imposed, the designer must
ensure that both analog and digital signals meet the transition specification.
T2 is the worst-case time needed for a powered-up module to switch between
channels after a valid channel selection. This time does not include external
overhead for loading a desired channel in the serial channel-selection mode.
T3 is the time to receiver readiness from the PDN line going high. Receiver
readiness is determined by valid data on the DATA line. This assumes an
incoming data stream and the presence of stable supply on VCC.
T4 is the time to receiver readiness from the application of VCC. Receiver
readiness is determined by valid data on the DATA line. This assumes an
incoming data stream and the PDN line is high or open.
6
–
There are four major timing considerations to be aware of when designing with
the HP3 Series receiver. These are shown in the table below.
RECEIVING DATA
Once an 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 modules do not incorporate internal encoding
or decoding, the user has tremendous flexibility in how data is handled.
It is important to separate the types of transmissions that are technically possible
from those that are legally allowed in the country of operation. Application Notes
AN-00126, AN-00140 and Part 15, Section 249 of the FCC rules should be
reviewed for details on acceptable transmission content in the U.S.
If you want to transfer simple control or status signals (such as button presses)
and your product does not have a microprocessor or you wish to avoid protocol
development, consider using an encoder / decoder IC set. These chips are
available from several manufacturers, including Linx. They take care of all
encoding and decoding functions and provide a number of data lines to which
switches can be directly connected. Address bits are usually provided for
security and to allow the addressing of multiple receivers independently. These
ICs are an excellent way to bring basic remote control products to market quickly
and inexpensively. It is also a simple task to interface with inexpensive
microprocessors or one of many IR, remote control, DTMF, or modem ICs.
Page 9
CHANNEL SELECTION
Parallel Selection
SERIAL CHANNEL SELECTION TABLE
CS2
0
0
0
0
1
1
1
1
CS1
0
0
1
1
0
0
1
1
CS0
0
1
0
1
0
1
0
1
Channel
0
1
2
3
4
5
6
7
Frequency
903.37
906.37
907.87
909.37
912.37
915.37
919.87
921.37
All HP3 receiver models feature eight
parallel selectable channels. Parallel
Mode is selected by grounding the
MODE line. In this mode, channel
selection is determined by the logic
states of pins CS0, CS1, and CS2, as
shown in the adjacent table. A ‘0’ Table 2: Parallel Channel Selection Table
represents ground and a ‘1’ the positive supply. The on-board microprocessor
performs all PLL loading functions, eliminating external programming and
allowing channel selection via DIP switches or a product’s processor.
Serial Selection
In addition to the Parallel Mode, PS versions of the HP3 also feature 100 serially
selectable channels. The Serial Mode is entered when the MODE line is left open
or held high. In this condition, CS1 and CS2 become a synchronous serial port,
with CS1 serving as the clock line and CS2 as the data line. The module is easily
programmed by sending and latching the binary number (0 to 100) of the desired
channel (see the adjacent Serial Channel Selection Table). With no additional
effort, the module’s microprocessor handles the complex PLL loading functions.
The Serial Mode is
Variable Data
Note 2
straightforward; however, Data
minimum timings and bit
Note 1
1
2
3
4
5
6
7
8
order must be followed. Clock
T0
Loading is initiated by
1ms
taking the clock line high
Note 3
T3
T4
8µs
and the data line low as
T2
5µs
T1
5µs
shown.
The
eight-bit
25µs
1)
Loading
begins
when
clock line is high and data line is taken low
channel number is then
clocked-in one bit at a 2) Ensure that edge is fully risen prior to high-clock transition
3) Both lines high triggers automatic latch
time, with the LSB first.
(T0) Time between packets or prior to data startup ................................1mS
(T1) Data-LO / Clock-HI to Data-LO / Clock-LO .......................................25µS
(T2) Clock-LO to Clock-HI ...........................................................................5µS
(T3) Clock-HI to Clock-LO ...........................................................................8µS
(T4) Data-HI / Clock-HI .................................................................................5µS
Total Packet Time ......................................................................................157µS
min.
min.
min.
min.
min.
min.
Figure 13: PLL Serial Data Timing
There is no maximum time for this process, only the minimum times that must be
observed. After the eighth bit, both the clock and data lines should be taken high
to trigger the automatic data latch. A typical software routine can complete the
loading sequence in under 200uS. Sample code is available on the Linx website.
NOTE: When the module is powered up in the Serial Mode, it will default to channel 50 until changed
by user software. This allows testing apart from external programming and prevents out-of-band
operation. When programmed properly, the dwell time on this default channel can be less than 200uS.
Channel 50 is not counted as a usable channel since data errors may occur as transmitters also default
to channel 50 on startup. If a loading error occurs, such as a channel number >100 or a timing problem,
the receiver will default to serial channel 0. This is useful for debugging as it verifies serial port activity.
Page 10
CHANNEL
TX FREQUENCY
0
902.62
1
902.87
2
903.12
3
903.37
4
903.62
5
903.87
6
904.12
7
904.37
8
904.62
9
904.87
10
905.12
11
905.37
12
905.62
13
905.87
14
906.12
15
906.37
16
906.62
17
906.87
18
907.12
19
907.37
20
907.62
21
907.87
22
908.12
23
908.37
24
908.62
25
908.87
26
909.12
27
909.37
28
909.62
29
909.87
30
910.12
31
910.37
32
910.62
33
910.87
34
911.12
35
911.37
36
911.62
37
911.87
38
912.12
39
912.37
40
912.62
41
912.87
42
913.12
43
913.37
44
913.62
45
913.87
46
914.12
47
914.37
48
914.62
49
914.87
50*
915.12
*See NOTE on previous page.
RX LO
CHANNEL
867.92
868.17
868.42
868.67
868.92
869.17
869.42
869.67
869.92
870.17
870.42
870.67
870.92
871.17
871.42
871.67
871.92
872.17
872.42
872.67
872.92
873.17
873.42
873.67
873.92
874.17
874.42
874.67
874.92
875.17
875.42
875.67
875.92
876.17
876.42
876.67
876.92
877.17
877.42
877.67
877.92
878.17
878.42
878.67
878.92
879.17
879.42
879.67
879.92
880.17
880.42
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
TX FREQUENCY
915.37
915.62
915.87
916.12
916.37
916.62
916.87
917.12
917.37
917.62
917.87
918.12
918.37
918.62
918.87
919.12
919.37
919.62
919.87
920.12
920.37
920.62
920.87
921.12
921.37
921.62
921.87
922.12
922.37
922.62
922.87
923.12
923.37
923.62
923.87
924.12
924.37
924.62
924.87
925.12
925.37
925.62
925.87
926.12
926.37
926.62
926.87
927.12
927.37
927.62
= Also available in Parallel
RX LO
880.67
880.92
881.17
881.42
881.67
881.92
882.17
882.42
882.67
882.92
883.17
883.42
883.67
883.92
884.17
884.42
884.67
884.92
885.17
885.42
885.67
885.92
886.17
886.42
886.67
886.92
887.17
887.42
887.67
887.92
888.17
888.42
888.67
888.92
889.17
889.42
889.67
889.92
890.17
890.42
890.67
890.92
891.17
891.42
891.67
891.92
892.17
892.42
892.67
892.92
Mode
Page 11
The figure below shows a typical RS-232 circuit using the HP3 Series receiver
and a Maxim MAX232. The receiver outputs a serial data stream and the
MAX232 converts that to RS-232 compliant signals. The MODE line is grounded
so the channels are selected by the DIP switches.
Despite this transparency and ease of use, it must be recognized that there are
distinct differences between a wired and a wireless environment. Issues such as
interference and contention must be understood and allowed for in the design
process. To learn more about protocol considerations, we suggest you read Linx
Application Note AN-00160.
Errors from interference or changing signal conditions can cause corruption of
the data packet, so it is generally wise to structure the data being sent into small
packets. This allows errors to be managed without affecting large amounts of
data. A simple checksum or CRC could be used for basic error detection. Once
an error is detected, the protocol designer may wish to simply discard the corrupt
data or implement a more sophisticated scheme to correct it.
INTERFERENCE CONSIDERATIONS
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.
C1
4.7uF
+ C2
4.7uF
DB-9
+
C3
4.7uF
C4
4.7uF
+
1
2
3
4
5
6
7
8
C1+
V+
C1C2+
C2VT2OUT
R2IN
GND
4
9
5
VCC
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
ANT
GND
GND
GND
GND
GND
GND
GND
NC
CS0
CS1 / SS CLOCK
CS2 / SS DATA
PDN
RSSI
MODE
VCC
AUDIO
DATA
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
GND
Figure 14: HP3 Receiver and MAX232 IC
GND
GND
GSHD
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.
GSHD
5
The figure below shows a circuit using the QS Series USB module. The QS
converts the data from the receiver into USB compliant signals to be sent to a
PC. The MODE line is high, so the module is in Serial Channel Select mode. The
RTS and DTR lines are used to load the channels. Application Note AN-00155
shows sample source code that can be adapted to use on a PC. The QS Series
Data Guide and Application Note AN-00200 discuss the hardware and software
set-up required for QS Series modules.
USB-B
Page 12
1
6
2
7
3
GND
GND
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.
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.
VCC
GND
T1OUT
R1IN
R1OUT
T1IN
T2IN
R2OUT
16
15
14
13
12
11
10
9
MAX232
C5
4.7uF
6
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.
VCC
VCC
+
While many RF solutions impose data formatting and balancing requirements,
Linx RF modules do not encode or packetize the signal content in any manner.
The received signal will be affected by such factors as noise, edge jitter, and
interference, but it is not purposefully manipulated or altered by the modules.
This gives the designer tremendous flexibility for protocol design and interface.
TYPICAL APPLICATIONS
+
PROTOCOL GUIDELINES
4
GND
3
2
DAT 1
5V
GND
GND
1
2
3
4
5
6
7
8
USBDP
RI
USBDM
DCD
GND
DSR
VCC
DATA_IN
SUSP_IND DATA_OUT
RX_IND
RTS
TX_IND
CTS
485_TX
DTR
SDM-USB-QS
16
15
13
12
11
10
9
1
2
3
4
5
6
GND
7
8
9
10
11
12
13
VCC 14
16
17
18
ANT
GND
GND
GND
GND
GND
GND
GND
NC
CS0
CS1 / SS CLOCK
CS2 / SS DATA
PDN
RSSI
MODE
VCC
AUDIO
DATA
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
Figure 15: HP3 Receiver and Linx QS Series USB Module
The receiver can also be connected to a microcontroller, which will interpret the
data and take specific actions. A UART may be employed or an I / O line may be
used to continuously monitor the DATA line for a valid packet. The receiver may
be connected directly to the microcontroller without the need for buffering or
amplification.
Page 13
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 (<1/8in.) to the module. One
common form of transmission line is a coax cable, another is the microstrip. This
term refers to a PCB trace running over a ground plane that is designed to serve
as a transmission line between the module and the antenna. The width is based
on the desired characteristic impedance of the line, the thickness of the PCB,
and the dielectric constant of the board material. For standard 0.062in thick FR4 board material, the trace width would be 111 mils. The correct trace width can
be calculated for other widths and materials using the information below. Handy
software for calculating microstrip lines is also available on the Linx website,
www.linxtechnologies.com.
Trace
Figure 16: Suggested PCB Layout
Board
During prototyping, the module should be soldered to a properly laid-out circuit
board. The use of prototyping or “perf” boards will result in horrible performance
and is strongly discouraged.
Ground plane
No conductive items should be placed within 0.15in of the module’s top or sides.
Do not route PCB traces directly under the module. The underside of the module
has numerous signal-bearing traces and vias that could short or couple to traces
on the product’s circuit board.
The module’s ground lines should each have their own via to the ground plane
and be as short as possible.
AM / OOK receivers are particularly subject to noise. The module should, as
much as reasonably possible, be isolated from other components on your PCB,
especially high-frequency circuitry such as crystal oscillators, switching power
supplies, and high-speed bus lines. Make sure internal wiring is routed away
from the module and antenna, and is secured to prevent displacement.
The power supply filter should be placed close to the module’s VCC line.
In some instances, a designer may wish to encapsulate or “pot” the product.
Many Linx customers have done this successfully; however, there are a wide
variety of potting compounds with varying dielectric properties. Since such
compounds can considerably impact RF performance, it is the responsibility of
the designer to carefully evaluate and qualify the impact and suitability of such
materials.
The trace from the module to the antenna should be kept as short as possible.
A simple trace is suitable for runs up to 1/8-inch for antennas with wide
bandwidth characteristics. For longer runs or to avoid detuning narrow bandwidth
antennas, such as a helical, use a 50-ohm coax or 50-ohm microstrip
transmission line as described in the following section.
Page 14
Figure 17: Microstrip Formulas
Dielectric Constant Width/Height (W/d)
Effective Dielectric
Constant
Characteristic
Impedance
4.80
4.00
1.8
2.0
3.59
3.07
50.0
51.0
2.55
3.0
2.12
48.0
Page 15
PAD LAYOUT
AUTOMATED ASSEMBLY
The following pad layout diagram is designed to facilitate both hand and
automated assembly.
Pinned Receiver
For high-volume assembly, most users will want to auto-place the modules. The
modules have been designed to maintain compatibility with reflow processing
techniques; however, due to the their hybrid nature, certain aspects of the
assembly process are far more critical than for other component types.
Surface-Mount Receiver
0.065
0.060
0.100
Following are brief discussions of the three primary areas where caution must be
observed.
0.090
0.060
0.750
Reflow Temperature Profile
The single most critical stage in the automated assembly process is the reflow
stage. The reflow profile below should not be exceeded, 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 remaining within the limits mandated by the modules.
The figure below shows the recommended reflow oven profile for the modules.
0.030 Dia. Finished
0.100
Figure 18: Recommended PCB Layout
PRODUCTION GUIDELINES
300
The modules are housed in a hybrid SMD package that supports hand or
automated assembly techniques. Since the modules contain discrete
components internally, the assembly procedures are critical to ensuring the
reliable function of the modules. The following procedures should be reviewed
with and practiced by all assembly personnel.
Pads located on the bottom of the
module are the primary mounting
surface. 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 underside. This allows for
very quick hand soldering for
prototyping and small volume
production.
Soldering Iron
Tip
217°C
200
185°C
180°C
150
125°C
50
Castellations
0
30
60
90
120
150
180
210
240
270
300
330
360
Time (Seconds)
Figure 19: Soldering Technique
If the recommended pad guidelines have been followed, the pads will protrude
slightly past the edge of the module. Use a fine soldering tip to heat the board
pad and the castellation, then introduce solder to the pad at the module’s edge.
The solder will wick underneath the module, providing reliable attachment. Tack
one module corner first and then work around the device, taking care not to
exceed the times listed below.
Absolute Maximum Solder Times
Hand-Solder Temp. TX +225°C for 10 Seconds
Hand-Solder Temp. RX +225°C for 10 Seconds
Recommended Solder Melting Point +180°C
Reflow Oven: +220°C Max. (See adjoining diagram)
Page 16
235°C
100
Solder
PCB Pads
Recommended Non-RoHS Profile
255°C
250
Temperature (oC)
HAND ASSEMBLY
Recommended RoHS Profile
Max RoHS Profile
Figure 20: Maximum Reflow Profile
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 modules not be
subjected to shock or vibration during the time solder is liquid. Should a shock
be applied, some internal components could be lifted from their pads, causing
the module to not function properly.
Washability
The modules are wash resistant, but are not hermetically sealed. Linx
recommends wash-free manufacturing; however, the modules can be subjected
to a wash cycle provided that a drying time is allowed prior to applying electrical
power to the modules. The drying time should be sufficient to allow any moisture
that may have migrated into the module to evaporate, thus eliminating the
potential for shorting damage during power-up or testing. If the wash contains
contaminants, the performance may be adversely affected, even after drying.
Page 17
ANTENNA CONSIDERATIONS
The choice of antennas is a critical
and
often
overlooked
design
consideration.
The
range,
performance, and legality of an RF link
are critically dependent upon the
antenna. While adequate antenna
performance can often be obtained by
trial and error methods, antenna
design and matching is a complex
task. A professionally designed Figure 21: Linx Antennas
antenna, such as those from Linx, will
help ensure maximum performance and FCC compliance.
Linx transmitter modules typically have an output power that is slightly higher
than the legal limits. This allows the designer to use an inefficient antenna, such
as a loop trace or helical, to meet size, cost, or cosmetic requirements and still
achieve full legal output power for maximum range. If an efficient antenna is
used, then some attenuation of the output power will likely be needed. This can
easily be accomplished by using the LADJ line or a T-pad attenuator. For more
details on T-pad attenuator design, please see Application Note AN-00150.
A receiver antenna should be optimized for the frequency or band in which the
receiver operates and to minimize the reception of off-frequency signals. The
efficiency of the receiver’s antenna is critical to maximizing range performance.
Unlike the transmitter antenna, where legal operation may mandate attenuation
or a reduction in antenna efficiency, the receiver’s antenna should be optimized
as much as is practical.
It is usually best to utilize a basic quarter-wave whip until your prototype product
is operating satisfactorily. Other antennas can then be evaluated based on the
cost, size, and cosmetic requirements of the product. You may wish to review
Application Note AN-00500 “Antennas: Design, Application, Performance”
ANTENNA SHARING
In cases where a transmitter and receiver
VDD
module are combined to form a transceiver,
Transmitter
0.1μF
it is often advantageous to share a single
Module 0.1μF
Antenna
antenna. To accomplish this, an antenna
0.1μF
GND
switch must be used to provide isolation
0.1μF
between the modules so that the full
GND
Receiver
Module
transmitter output power is not put on the
0.1μF
sensitive front end of the receiver. There
Select
are a wide variety of antenna switches that
Figure
22:
Typical
Antenna
Switch
are cost-effective and easy to use. Among
the most popular are switches from Macom and NEC. Look for an antenna
switch that has high isolation and low loss at the desired frequency of operation.
Generally, the Tx or Rx status of a switch will be controlled by a product’s
microprocessor, but the user may also make the selection manually. In some
cases, where the characteristics of the Tx and Rx antennas need to be different
or antenna switch losses are unacceptable, it may be more appropriate to utilize
two discrete antennas.
Page 18
GENERAL ANTENNA RULES
The following general rules should help in maximizing antenna performance.
1. Proximity to objects such as a user’s hand, body, or metal objects will cause an
antenna to detune. For this reason, the antenna shaft and tip should be
positioned as far away from such objects as possible.
2. Optimum performance will be obtained
from a 1/4- or 1/2-wave straight whip
mounted at a right angle to the ground
plane. In many cases, this isn’t desirable
OPTIMUM
for practical or ergonomic reasons, thus,
NOT RECOMMENDED
USEABLE
an alternative antenna style such as a
helical, loop, or patch may be utilized Figure 23: Ground Plane Orientation
and the corresponding sacrifice in performance accepted.
3. If an internal antenna is to be used, keep it away from other metal components,
particularly large items like transformers, batteries, PCB tracks, and ground
planes. In many cases, the space around the antenna is as important as the
antenna itself. Objects in close proximity to the antenna can cause direct
detuning, while those farther away will alter the antenna’s symmetry.
4. In many antenna designs, particularly 1/4-wave
VERTICAL λ/4 GROUNDED
ANTENNA (MARCONI)
whips, the ground plane acts as a counterpoise,
DIPOLE
forming, in essence, a 1/2-wave dipole. For this
ELEMENT
reason, adequate ground plane area is essential.
The ground plane can be a metal case or ground-fill
areas on a circuit board. Ideally, it should have a
GROUND
surface area > 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 24: 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 25: Remote Ground Plane
Page 19
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 20
®
www.linxtechnologies.com
•
•
•
•
•
Latest News
Data Guides
Application Notes
Knowledgebase
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.connectorcity.com
Through its Connector City division, Linx offers a wide
selection of high-quality RF connectors, including FCCcompliant types such as RP-SMAs that are an ideal
match for our modules and antennas. Connector City
focuses on high-volume OEM requirements, which
allows standard and custom RF connectors to be offered
at a remarkably low cost.
Page 21
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 FCC prescreening, and 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
Office of Engineering and Technology Laboratory Division
7435 Oakland Mills Road
Columbia, MD 21046-1609
Phone: (301) 362-3000 Fax: (301) 362-3290 E-Mail: [email protected]
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 22
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-00126
Considerations For Operation Within The 902-928MHz Band
AN-00130
Modulation Techniques For Low-Cost RF Data Links
AN-00140
The FCC Road: Part 15 From Concept To Approval
AN-00155
Serial Loading Techniques for the HP Series 3
AN-00160
Considerations For Sending Data Over a Wireless Link
AN-00500
Antennas: Design, Application, Performance
Page 23
WIRELESS MADE SIMPLE ®
U.S. CORPORATE HEADQUARTERS
LINX TECHNOLOGIES, INC.
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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.
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sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for
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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.
© 2008 by Linx Technologies, Inc. The stylized Linx logo,
Linx, “Wireless Made Simple”, CipherLinx, and the stylized
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