LT Series
Basic Evaluation Kit
User's Guide
Warning: Linx radio frequency ("RF") products may be
used to control machinery or devices remotely, including machinery
or devices that can cause death, bodily injuries, and/or property
damage if improperly or inadvertently triggered, particularly in industrial
settings or other applications implicating life-safety concerns. No Linx
Technologies product is intended for use in any application without
redundancies where the safety of life or property is at risk.
!
The customers and users of devices and machinery controlled with
RF products must understand and must use all appropriate safety
procedures in connection with the devices, including without limitation,
using appropriate safety procedures to prevent inadvertent triggering by
the user of the device and using appropriate security codes to prevent
triggering of the remote controlled machine or device by users of other
remote controllers.
Do not use this or any Linx product to trigger an action directly
from the data line or RSSI lines without a protocol or encoder/
decoder to validate the data. Without validation, any signal from
another unrelated transmitter in the environment received by the
module could inadvertently trigger the action. This module does not
have data validation built in.
All RF products are susceptible to RF interference that can prevent
communication. RF products without frequency agility or hopping
implemented are more subject to interference. This module does not
have frequency agility built in.
Do not use any Linx product over the limits in this data guide.
Excessive voltage or extended operation at the maximum voltage could
cause product failure. Exceeding the reflow temperature profile could
cause product failure which is not immediately evident.
Do not make any physical or electrical modifications to any Linx
product. This will void the warranty and regulatory and UL certifications
and may cause product failure which is not immediately evident.
Table of Contents
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Introduction
Ordering Information
LT Series Transceiver Evaluation Board
Board Objects
Theory of Operation
Using the Kit
Development Using the Prototyping Area
Range Testing
Using the Boards as a Design Reference
About Antennas
In Closing
Online Resources
Transceiver Evaluation Board Schematics
LT Series Basic Evaluation Kit
User's Guide
Figure 1: LT Series Basic Evaluation Kit
Introduction
Linx LT Series RF transceiver modules offer a simple, efficient and
cost-effective method of adding wireless communication capabilities to any
product. The Basic Evaluation Kit gives a designer all the tools necessary to
correctly and legally incorporate the LT Series modules into an end product.
The evaluation boards themselves serve several important functions:
• Rapid Module Evaluation: The boards allow the performance of the LT
Series modules to be evaluated quickly in a user’s environment.
• Range Testing: Using the on-board transcoders to generate a duplex
transmission, a pair of evaluation boards can be used to evaluate the
range performance of the modules.
• Design Benchmark: The boards provide a known benchmark against
which the performance of a custom design may be judged.
• Application Development: An onboard prototyping area allows for the
development of custom circuits directly on the evaluation board. All
signal lines are available on a header for easy access.
This kit includes 4 LT Series transceivers*†, 2 MT Series transcoders*, 2
extra PCB-mount RP-SMA connectors, 2 evaluation boards, 2 HD or CW
Series antennas, 4 AAA batteries, and full documentation.
* One part is soldered to each board.
†Two extras are for use on your first prototype boards.
– 1–
Revised 3/18/2015
LT Series Transceiver Evaluation Board
Ordering Information
2
Ordering Information
Part Number
Description
EVAL-***-LT
LT Series Basic Evaluation Kit
17
*** = 315, 418 (Standard), 433MHz
15
14
1
Figure 2: Ordering Information
9
5
6
16
Warning: This product incorporates numerous static-sensitive
components. Always wear an ESD wrist strap and observe proper ESD
handling procedures when working with this device. Failure to observe
this precaution may result in module damage or failure.
4
3
7
8
2
11
10
13
1
6
12
4
3
9
5
7
8
Figure 3: LT Series Transceiver Evaluation Boards
Board Objects
1. Battery – 3VDC
2. Power Switch
3. Prototyping Area
4. Breakout Header
5. Confirmation LED
6. Routing Switches
7. LT Series Transceiver Module
8. MT Series Transcoder Chip
9. RP-SMA Antenna Connector
– 2–
10. LED Button – D2
11. Buzzer Button – D3
12. LED – D0
13. Buzzer – D1
14. LED Button – D0
15. Buzzer Button – D1
16. LED – D2
17. Buzzer – D3
– 3–
Theory of Operation
Development Using the Prototyping Area
The two transceiver evaluation boards are identical, but they are populated
slightly differently. The MT Series transcoder is both an encoder and a
decoder, with the input or output nature of each line being determined by
how the board is populated. One board has buttons S0 and S1 populated,
making those lines inputs. On the other board, those lines are connected
to the buzzer and LED, respectively. Conversely, the first board has lines
D2 and D3 connected to the buzzer and LED, while the second board has
buttons S2 and S3 populated. This allows for bidirectional remote control.
To use the kit, simply attach the antennas, turn on the power, and press
one or both of the buttons on a board. When S0 or S2 is pressed, the
buzzer sounds; when S1 or S3 is pressed, the LED turns on.
In addition to their evaluation functions, the boards may also be used for
product development. They feature a prototyping area to facilitate the
addition of application-specific circuitry. This area has a connection to VCC
at the bottom and to ground at the top which can be used to power any
added circuitry.
Both boards have a confirmation LED. When one transcoder sends a
command to the second transcoder, the second transcoder sends a
confirmation back to the first transcoder indicating that the command was
received and the action performed. When the first transcoder receives the
confirmation, it turns on the CONFIRM LED to indicate this. This feature
offers the ability to range test without needing to be in visual or hearing
range of both boards.
The MT Series Transcoder Data Guide goes into the many features of the
transcoders in detail, but this is the only set-up required for operation of
this kit.
Note: If added circuitry requires a higher current than can be provided
by the batteries, the batteries must be removed and the board powered
from an external source.
The holes are plated and set at 0.1" on center with a 0.04" diameter,
making it easy to add most industry-standard SIP and DIP packages to the
board.
All of the lines from the transceiver have been wired out to a row of plated
holes on the right side of the prototyping area. Four of the data lines from
the transcoder have also been wired out. This allows for easy access to
connect external circuitry to the modules and the transcoder. Three lines
from the transceiver (DATA, T/R_SEL, and PDN) have been routed to
switches. The switches connect the lines to either the transcoder or the
prototyping area. This allows the transceiver to be conveniently switched
between the transcoder and application circuitry during testing.
Using the Kit
Using the kit is straightforward. Simply attach the antennas, turn on the
power, and press buttons on one of the boards. When S0 or S2 is pressed,
the LED turns on; when S1 or S3 is pressed, the buzzer sounds. When any
button is pressed, the CONFIRM LED lights up to indicate that the other
side got the command.
– 4–
– 5–
Range Testing
Several complex mathematical models exist for determining path loss in
many environments. These models vary as the transmitter and receiver are
moved from indoor operation to outdoor operation. Although these models
can provide an estimation of range performance in the field, the most
reliable method is to simply perform range tests using the transmitter and
receiver in the intended operational environment.
Basic range testing can be performed with the transceiver evaluation
boards. To prepare the board for range testing, turn it on by switching the
power switch to the ON position. Pressing S0 or S2 activates the buzzer on
the receiver board, while S1 or S3 activates the LED. The CONFIRM LED
provides an indication that the signal has traveled round trip, so only one
person is needed to conduct range testing.
As the maximum range of the link in an area is approached, it is not
uncommon for the signal to cut in and out as the transmitter moves. This
is normal and can result from other interfering sources or fluctuating signal
levels due to multipath. Multipath results in cancellation of the transmitted
signal as direct and reflected signals arrive at the receiver at differing times
and phases. The areas in which this occurs are commonly called “nulls”
and simply walking a little further usually restores the signal. If this does not
restore the signal, then the maximum effective range of the link has been
reached.
transceiver’s RSSI voltage with the other transceiver turned off to determine
if ambient interference is present. If this fails to resolve the issue, please
contact Linx technical support.
Using the Boards as a Design Reference
The basic evaluation boards included in this kit are very simple, yet they
illustrate some important techniques that should be incorporated into the
board layout. The module’s mounting pads extend slightly past the edge of
the part. This eases hand assembly and allows for better heat conduction
under the part if rework is necessary. A full ground plane fill is placed on the
bottom of the board. This ground plane serves three important purposes:
First, since a quarter-wave antenna is employed, the ground plane is
critical to serve as a counterpoise (please see Application Note AN-00500
“Antennas: Design, Application, and Performance” for details on how a
ground plane affects antenna function).
Second, a ground plane suppresses the transfer of noise between stages
of a product as well as unintentional radiation of noise into free space.
Third, a ground plane allows for the implementation of a microstrip feed
between the module and the antenna. The term microstrip refers to a PCB
trace running over a ground plane that is designed to serve as a 50-ohm
transmission line. See the LT Series data guide or the calculator available
on our website for details on microstrip calculations.
Since the evaluation boards are intended for use by design engineers, they
are not FCC certified. The transmitter section has been set to approximate
legal limits by resistor R9 so that the range test results will approximate the
results from a well-designed, certified product. For applications where Part
15 limits are not applicable or output levels can be legally raised due to
protocol duty cycle, R9 can be changed according to the Output Power vs.
LADJ Resistance graph in the LT Series Transceiver Module Data Guide.
To achieve maximum range, keep objects such as your hand away from
the antenna and ensure that the antenna on the transmitting board has a
clear and unobstructed line-of-sight path to the receiving board. Range
performance is determined by many interdependent factors. If the range
you are able to achieve is significantly less than specified by Linx for the
products you are testing, then there is likely a problem with either the board
or the ambient RF environment in which the board is operating. First, check
the battery, switch positions, and antenna connection. Next, measure the
– 6–
– 7–
About Antennas
Online Resources
The choice of antennas is one of the most critical and often overlooked
design considerations. The range, performance, and legality of an RF link
are critically dependent upon the type of antenna employed. Linx offers
a variety of antenna styles that can be considered for a design. Included
with your kit are HD Series (315MHz) or CW Series (418MHz and 433MHz)
connectorized whip antennas that should be connected prior to using the
kit. Despite the fact that the antenna is not centered on the board’s ground
plane, it exhibits a VSWR of <1.7 and suitably demonstrates the module’s
best practical performance.
In Closing
Here at Linx, “Wireless Made Simple” is more than just our motto, it is our
commitment. A commitment to the highest caliber of product, service,
and support. That is why, should you have questions or encounter any
difficulties using the evaluation kit, you’ll be glad to know many resources
are available to assist you. First, check carefully for the obvious, then
visit our website at www.linxtechnologies.com or call +1 541 471 6256
between 8AM and 4PM Pacific Time to speak with an application engineer.
Legal Notice: All Linx kits and modules are designed in keeping with
high engineering standards; however, it is the responsibility of the user to
ensure that the products are operated in a legal and appropriate manner.
The purchaser understands that legal operation may require additional
permits, approvals, or certifications prior to use, depending on the
country of operation.
www.linxtechnologies.com
If you have questions regarding any Linx product and have Internet access,
make www.linxtechnologies.com your first stop. 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, including:
•
Manual and Software Updates
•
Latest News
•
Data Guides
•
Application Notes
•
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 GPS
antennas, Antenna Factor likely has an
antenna for you, or can design one to meet
your requirements.
by
Figure 4: Antenna Factor Antennas
– 8–
– 9–
TRANSCEIVER EVALUATION BOARD
TRANSCEIVER EVALUATION BOARD
Power Supply Section
Duplex Range Test Section
VCC
Transceiver Evaluation
Board Schematics
TRANSCEIVER EVALUATION BOARD
TRANSCEIVER EVALUATION
BOARD
U3
S8
Power Supply Section
VCC
VCC
+ C1
10uF
VCCGND
TRANSCEIVER
LED
Duplex Range Test Section
GND
D0
R19
green
R17
100k
200 ohm
GND
S8
RF Module Section
+ C1 VCC
10uF
VCC
GND
RF
RF Module Section
B1
BAT-AAA
LED
S8
B1
GND
BAT-AAA
+ C1
ANT1
GND
10uF
CONREVSMA001
VCC
U1
1
RF Supply Section
LADJ
Figure 5: Power
1
GND
+ C1 GND
2
B1
GNDBAT-AAA
GND10uF
VCC
3
S4
R17
200 ohm
10
SW-SPDT
S5
VCC
GND
S4
PDN
TS1
6
9
RSSI
8
A REF
7
DATA
Header Section Figure 6: RF Module Section
TRSEL
6
PDN
5
4
D0
TS1
3
D1
HeaderTS1
Section
9
RSSI
2
D2
8RSSI
A REF
9
D3
1
7A REF
DATA
8
Test Strip
1
6DATA
TRSEL
7
6 TS1 5TRSEL PDN
D0
5
9 4PDN RSSI
D1
4
A REF
8 3D0
3
D2
DATA
7 2D1
2
D3
TRSEL
6 1D2
Header Section
1
5
D3
PDN
Test Strip D0
1
Test Strip41
3
2
1
DATA
PDN
T/R SEL
ANALOG
DATA
TRM-XXX-LT
7
R0
GND
100K
GND
100K
GND
R1 GND
GND
100K
D1
D2
D3
R1
GND
Test Strip 1
100K
R2
GND
GND
GND
100K
R2
GND
GND
GND
GND
GND
DATAMT
LED
0 ohm
DATA
S0 SW-SPDT
S1
VCC
VCC
VCC
0 ohm R21
R1 R2
R18 BUZZER
R21
LED
S1 BUZZER
0 ohm
100K100K
0
ohm
0 ohm
VCC
S2
R2
1
2
R19 3
100k
4
R20 5
A
A`
R20VCC
0.01uF
143 6
BUZZER
C`
10k
12 9
F` D
13
11 8
E D`
U3
C2
B1
A
F
GND
4 7 GND
B`
12
F` VCC
5
2
B`0.01uF
A`
E
C3
E`
B
B
11
6F
R6
10k
6
GND
C`4
7
100K
GND
10
7F`
B`
D
GND
9
R21
S3
D`
0 ohm
R3
R22
R3
0100K
ohm
R6 R12
100k
100K
R3
R22
100K
0 ohm
12
BZ1
9
GND
BUZZER
8
BUZZER
R5
100K
VCC
GND
GND
R6
D6
D5
R4
R13
GND
R7
GND
D7
D4
100K GND
100K
100K
CRT/LRN
D3
D3
100K
R7
ENC_SEL
LATCH
GND
R14
GND
R12
R5
R6GND
U2 SER_IO
BAUD_SEL
GND
100K
GND
GND
100K
CONFIRM
MODE_IND
100k
100K
R12 100K
R5
GND
VCC
VCC
GND
U2
PDNMT
TR_PDN
D2
D2
GND
GND
D6
D5
R7
R13
R4
100K
TR_SEL GND
D1
D1
GND
R15 VCC D10 VCC TRSELMT
GND 100k GND
D7
D4
DATAMT
TR_DATA
D0
D0
100K
D6
D5
R13GND
R4
100K
100K
D3
CRT/LRN
D3
200 ohm
GND
GND
D7
D4
R12
R5 GND
ENC_SEL
LICAL-TRC-MT LATCH
U2
R14 LED0805 CRT/LRN
100K
D3
D3
GND
GND 100K GND
GND
SER_IO
BAUD_SEL
100K
LATCH GND GND GND
VCC ENC_SEL
VCC
R14 100k
100K
CONFIRM GND
MODE_IND
GND
SER_IO
BAUD_SEL
D6
D5
R13 8: Duplex Range Test Section
R4 D2
Figure
PDNMT
TR_PDN
D2
CONFIRM
MODE_IND
GND 100K
D7
D4
GND
D10
TRSELMT
TR_SEL
100K R15 PDNMT
100KD1
TR_PDN
D2
CRT/LRN
D3 D2
D3 D1
D0
DATAMT
TR_DATA
D0
D1
TRSELMT
TR_SEL
D1
ENC_SEL
LATCH
GND
R15 GND D10
R14200 ohm
GND
D0
DATAMT
TR_DATA
D0
GND
SER_IO
BAUD_SEL
GND
LICAL-TRC-MT
LED0805
200 ohm
100K
CONFIRM
MODE_IND
LED0805
GND
R15
D10
200 ohm
LED0805
LICAL-TRC-MT
PDNMT
TR_PDN
TRSELMT
TR_SEL
DATAMT
TR_DATA
D2
D1
D0
LICAL-TRC-MT
VCC
BUZZER
BUZZER
Figure 7: Header Section
– 10 –
D
13
U2
R18
R22
C`
BUZZER
GND
VCC
VCCVCC
S3 BUZZER
0 ohmVCC
E`
R7
VCC BUZZER
VCC LED
C
100K
S3
R18
14
CD4069UB
HEX
BUZZER
10 INVERTER
BZ1
CD4069UB HEX INVERTER
S2 S3
0 ohm
F
BUZZER
13
3
12
B
F`
U3
10k
R19
4
1
14 11
EVALUATION
BOARD
A B` VCC E
BUZZER
C2
100k
2 5 C
13 10
A`
F E`
U3
R22
R18 R3
LEDBUZZER
S2 LED
0100K
ohm100K 0 ohm
0VCC
ohm
100K
GND
R1
GND
GND
VCC LED
100K
GND
R23
R23
R21 LED
R23
BUZZER
100K
0 ohm
S0 LED
100K
0 ohm
0 ohm
S1 VCC
S2
S1
VCC
R0
R23
VCC
GND
R0 GND
100K
R0
TRSELMT
S0 DATAMT
DATA
SW-SPDT
TRSEL
DATA VCC
SW-SPDT
SW-SPDT
S6
S0
GND
S5
S6
8
2
14
8
BZ1
D`
11
E
C2
CD4069UB HEX INVERTER
7
8
10
5
GND
GND
C D`
E`
BUZZER
BZ1
CD4069UB
HEX
INVERTER
0.01uF
9
6
D
C`
0.01uF
D0
green
TRSELMT
GND
ANALOG
RSSI
TRM-XXX-LT
5
A REF
D0
green
C2
GND
GND
A REF
10k
R17
D0
200 ohmGND
green
PDNMT
PDNMT
TRSEL
SW-SPDT
PDN
S6
PDNMT
SW-SPDT
DATAMT
RF
RF
LADJ
VCC PDNS5
TRSELMT
1
DATA
5
8750 ohm SW-SPDT
S4
4
9 T/R 11
GND
2
A REF PDN VCC
SEL VCC
SW-SPDT
RSSI GNDA REF
RSSI
GND
PDNMT
S5
TRSEL
TRSELMT
6
7
5
8
SW-SPDT
3
10
2-5
A REF
T/R SEL GNDDATA
NC ANALOG
GND
Header Section A REF
S6 PDN
SW-SPDT
TRSEL
TRM-XXX-LT 7
DATAMT
6
4
9
GND
SW-SPDT
RSSI
R20
VCC
750 ohm
VCC
ANT1 2-5
GND
NC
GND
CONREVSMA001GND
U1 GND
R9
4
9
GND
1
12
RSSI
RF
RF RSSI
LADJPDN
ANT1
1
750 ohm
CONREVSMA001
5
U1
2
11 8
A
REF
A
REF
T/R
R9SEL
RF Module Section
GND
GND
VCC
VCC
1
12
RF
RF
LADJ
VCC
1
6
750
ohm
3
10 7
DATA
S4
ANT1 2-5
NC ANALOG11 GND
GND
2
GND
GND
VCC
VCC
CONREVSMA001
U14
TRM-XXX-LT
9 R9
GND
3
10
RSSI
RSSI
PDN
12
2-5
NC1
GND
GND
RF Module Section
LED
R9
12
11
VCC
R20
R17
200 ohm
Duplex Range Test Section
TRANSCEIVER EVALUATION BOARD
Power Supply Section
A
A`
TRANSCEIVER EVALUATION BOARD
B1
BAT-AAA
S8
VCC
1
100k
LED
TRANSCEIVER EVALUATION BOARD
Power Supply Section
R19
Duplex Range Test Section
– 11 –
D2
D1
D0
GND
GND
GND
Linx Technologies
159 Ort Lane
Merlin, OR, US 97532
Phone: +1 541 471 6256
Fax: +1 541 471 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 Data 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
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limitation, breach of contract, breach of warranty, strict liability, or negligence. Customer assumes all liability
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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,
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conveyed any license or right to the use or ownership of such items.
©2015 Linx Technologies. All rights reserved.
The stylized Linx logo, Wireless Made Simple, WiSE, CipherLinx and the stylized CL logo are trademarks of Linx Technologies.