HIGH-PERFORMANCE
LS SERIES
ENCODER/DECODER
WIRELESS MADE SIMPLE
®
LS SERIES ENCODER / DECODER DATA GUIDE
DESCRIPTION
The Linx LS Series encoders and
decoders provide an extremely simple, yet
reliable, protocol for the transmission of
switch closures or button contacts. This
series can find use in any basic, low-cost
remote control application. Simply take a
data line high on the encoder and a
corresponding line will go high on the
decoder. No programming or addressing is
required, making integration of the LS
extremely easy while maintaining a robust
link.
0.250
(6.35)
0.012
(0.29)
10˚
0.370
(9.40)
10˚
0.373
(9.46)
0.155
(3.94)
0.130
(3.30)
0.015
(0.38)
0.130
(3.30)
0.313
(7.04)
FEATURES
No addressing or programming
Easy to use
Very low current consumption
Four data lines
Easy serial interface
Selectable baud rates
High noise immunity
Standard PDIP package
0.058
(1.46)
0.018
(0.46)
0.100
(2.54)
Figure 1: Package Dimensions
0.313 (7.94)
0.100 (2.54)
APPLICATIONS INCLUDE
Range Testing
Simple Remote Control
Wire Elimination
Remote Status Monitoring
Lighting Control
0.018 (0.46)
Figure 2: PCB Layout Dimensions
ORDERING INFORMATION
PART #
DESCRIPTION
LICAL-ENC-LS001
LS Encoder
LICAL-DEC-LS001
LS Decoder
LS encoders / decoders supplied in tubes of 60 pcs.
All parts are RoHS compliant.
Revised 1/28/08
ELECTRICAL SPECIFICATIONS
Parameter
POWER SUPPLY
Operating Voltage
Supply Current:
At 2.0V V
CC
At 3.0V V
CC
At 5.0V V
CC
Power-Down Current:
At 2.0V V
CC
At 3.0V V
CC
At 5.0V V
CC
ENCODER / DECODER SECTION
Input Low
Input High
Output Low
Output High
Input Sink Current
Output Drive Current
ENVIRONMENTAL
Operating Temperature Range
V
CC
I
CC
–
–
–
I
PDN
–
–
–
V
IL
V
IH
V
OL
V
OH
–
–
–
-40
–
+125
°C
0.0
0.8 x V
CC
–
V
CC
- 0.7
–
–
–
–
–
–
–
–
0.15 x V
CC
V
CC
0.6
–
25
25
V
V
V
V
mA
mA
2
3
0.99
1.2
2.9
700
770
995
nA
nA
nA
340
500
800
450
700
1,100
µA
µA
µA
1
1
1
2.0
–
5.5
VDC
–
Designation
Min.
Typical
Max.
Units
Notes
PIN ASSIGNMENTS
LICAL-ENC-LS001
1
GND
VCC
2
D0
DATA_OUT
3
D1
D3
4
D2
SEL_BAUD
8
7
6
5
LICAL-DEC-LS001
1
GND
VCC
2
D0
DATA_IN
3
D1
D3
4
D2
SEL_BAUD
8
7
6
5
Figure 3: LS Series Encoder and Decoder Pin Assignments
Table 1: Electrical Specifications
ENCODER PIN ASSIGNMENTS
Pin Name
V
CC
Notes
1. Current consumption with no active loads.
2. For 3V supply, (0.15 x 3.0) = 0.45V max.
3. For 3V supply, (0.8 x 3.0) = 2.4V min.
Pin Number
I/O
Description
1
DATA_OUT
to
+6.5
to V
CC
+ 0.3
25
25
250
300
to
+125
to
+150
VDC
VDC
mA
mA
mA
mA
°C
°C
—
Positive Power Supply
ABSOLUTE MAXIMUM RATINGS
Supply Voltage V
CC
Any Input or Output Pin
Max. Current Sourced By Data Pins
Max. Current Sunk By Data Pins
Max. Current Into V
CC
Max. Current Out Of GND
Operating Temperature
Storage Temperature
-0.3
-0.3
2
SEL_BAUD
GND
D0-D3
O
Serial Data Output
4
I
Baud Rate Selection Pin
8
—
Ground
3, 5, 6, 7
-40
-65
I
Data Input Pins
DECODER PIN ASSIGNMENTS
Pin Name
V
CC
DATA_OUT
*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.
Pin Number
I/O
Description
1
—
Positive Power Supply
2
I
Serial Data Input
*CAUTION*
This product is a static-sensitive component. 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 device damage or failure.
Page 2
SEL_BAUD
GND
D0-D3
4
I
Baud Rate Selection Pin
8
—
Ground
3, 5, 6, 7
O
Data Output Pins
Page 3
PIN DESCRIPTIONS
V
CC
This is the positive power supply.
DATA_OUT
The encoder will output a serial data stream on this line.
DATA_IN
The decoder will monitor this line for data.
SEL_BAUD
This line is used to select the baud
rate of the serial data stream. The
state of the line allows the selection of
one of two possible baud rates, as
shown in the adjacent table.
SEL_BAUD
0
1
Table 2: Baud Rate Selection Table
DECODER OPERATION
The LS Series decoder begins by waiting for the DATA_IN line to transition from
low to high. At that point, the decoder will accept the data, check it for errors, and
confirm that the bytes are valid. If the data pass all of the checks, then the data
bits are output on the decoder’s data lines. If any of these checks fail, then the
decoder will ignore the received packet and look for the next one.
Baud Rate (bps)
2,400
9,600
The decoder has a built-in debounce circuit to guard against signal cutout. This
is a timer that maintains the current state of the data lines until changed by a
valid packet or until no valid packets are received for 131mS. After 131mS, the
decoder pulls all of the data lines to ground and goes back to sleep. This helps
protect devices attached to the decoder by smoothing out the output response.
Rapid switching resulting from lost packets could cause damage to devices,
such as relays or motors, that may be controlled by the decoder.
GND
These lines are connected to ground.
Data Lines
The LS Series has three data lines, D0 through D3. When any of these lines
goes high on the encoder, their states are recorded, encoded for transmission,
and then reproduced on the outputs of the decoder.
This debounce circuit helps in noisy environments and at the range limit of the
link where lost packets and cutouts are more frequent. The drawback is that
there is a 131mS lag time between the end of the transmission and when the
data lines are turned off. This is generally not a problem with manual remote
control applications, but must be taken into account in applications where timing
is critical.
TYPICAL APPLICATIONS
PRODUCTION CONSIDERATIONS
LS Series encoders and decoders are implemented in an industry standard 8-
Lead Plastic Dual In-Line Package (8-PDIP). The package and layout
dimensions are shown on Page 1. These components are leaded through-hole
parts and may be hand- or wave-soldered.
LS Series encoders and decoders would typically be used in remote control
applications to register button presses and activate circuitry in a remote device.
Figure 4 shows an example application circuit.
An SPDT switch is used in both circuits to set the baud rate. This switch will pull
the BAUD_SEL line to either ground or V
CC
for selection of one of the baud rates
listed in the Pin Descriptions section. The baud rate on both sides must match in
order for the encoder and decoder to correctly operate.
THEORY OF OPERATION
The Linx LS Series encoder and decoder are designed to register button presses
or contact closures. When a pin goes high on the encoder, a signal is sent to
make a corresponding pin go high on the decoder. The outputs of the decoder
can then be used to activate almost anything, from driving a LED or buzzer to
activating digital circuitry.
The LS Series does not require any programming or addressing and its simplicity
makes it a good choice for basic remote control devices that are designed to turn
something on and off.
Two pushbutton switches are connected to the data lines on the encoder. Since
none of the data lines have internal pull resistors, external resistors are used to
pull the data lines to ground when not in use. Without these resistors, the state
of the data lines can not be guaranteed and performance may not be predictable.
In this example, only two data lines are used, so the other two are tied directly to
ground. With this circuit, pressing either of the buttons will cause the data line to
go high and initiate a transmission.
ENCODER OPERATION
Upon power-up, the encoder enters sleep mode. As soon as one of the data lines
goes high, it will wake up and begin the transmit process.
First, the encoder will record the state of the data lines, encode for error
correction, and assemble the packet. It will then output the packet on the
DATA_OUT line. The encoder will repeat the transmission process for as long as
one of the data lines is high, otherwise it will go back to sleep. It will update the
state of the data lines with each packet, and it will finish the current transmission
even if all of the lines are pulled to ground.
Page 4
On the decoder side, a piezoelectric buzzer is attached directly to the D1 line.
When the button connected to the D1 line on the encoder is pressed, the buzzer
will sound. The D0 line is connected to a relay through a transistor buffer. The
decoder can output 25mA, which is sufficient to drive small relays, but may not
work for larger coils. The transistor is used to provide the higher current and
voltage required to activate a larger relay. With this circuit, when the D0 line goes
high, it will turn on the transistor, which will energize the relay and connect the
terminals.
Page 5
VCC
ENCODER
DECODER
Start Up
200k
VCC
GND
GND
RELAY OUT
GND
GND
VCC
2N2222
VCC
GND
2.2k
GND
BUZZER
GND
10k
D0
VCC
D1
D2
5
3 D3
4 SEL_BAUD
6
7
VCC
GND 8
RELAY-SPDT
200k
1
2
To Transmitter
VCC
GND
3 D3
4 SEL_BAUD
D1 6
D2 5
1 VCC
GND 8
2 DATA_OUT
D0 7
VCC
Sleep Mode
Start Up
GND
LICAL-ENC-LS001
Sleep Mode
Is the
DATA_IN line
high?
NO
YES
GND
LICAL-DEC-LS001
Are any data
lines high?
NO
Start Time-Out
timer
Figure 4: LS Series Application Circuits
YES
Get the data from
the data lines
131mS Time-Out?
YES
ONLINE RESOURCES
®
Encode for error
correction
NO
Receive data
www.linxtechnologies.com
•
•
•
•
•
Latest News
Data Guides
Application Notes
Knowledgebase
Software Updates
Create the packet
Check data for
errors
Send the packet
NO
Is the data
valid?
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make www.linxtechnologies.com your first stop. Our website is organized in an
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YES
Output the data on
the data lines.
Figure 5: LS Series Encoder Flowchart
Page 6
Figure 6: LS Series Decoder Flowchart
Page 7
WIRELESS MADE SIMPLE
®
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LINX TECHNOLOGIES, INC.
159 ORT LANE
MERLIN, OR 97532
PHONE: (541) 471-6256
FAX: (541) 471-6251
www.linxtechnologies.com
Disclaimer
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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
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