W-Linx Technology TXE-433-KH, TXE-418-KH, TXE-315-KH User Manual

DESCRIPTION

The KH Series is ideally suited for volume use
in OEM applications such as remote control and
command, and keyless entry. Housed in a
compact SMD package, it combines a highly­optimized RF transmitter with an on-board
encoder. When paired with a matching KH
Series receiver / decoder module, a reliable
wireless link is formed, capable of transferring
the status of 8 parallel inputs over distances in
excess of 300 feet. Ten tri-state address lines
provide 59,049 (3

10

) addresses for security and
uniqueness. No external RF components are
required (except an antenna), making
integration straightforward.

KH SERIES TRANSMITTER / ENCODER DATA GUIDE

WIRELESS MADE SIMPLE

®

Revised 10/12/06

Figure 1: Package Dimensions

 Remote Control / Command
 Keyless Entry
 Garage / Gate Openers
 Lighting Control
 Call Systems
 Home / Industrial Automation
 Fire / Security Alarms
 Remote Status Monitoring
 Wire Elimination

APPLICATIONS INCLUDE

 Low cost
 On-board encoder
 8 parallel binary inputs
 3

10

addresses for security and

uniqueness

 No external RF components

required

 Ultra-low power consumption
 Compact SMD package
 Stable SAW-based architecture
 Adjustable output power
 Transmit enable line
 No production tuning

FEATURES

PART # DESCRIPTION
TXE-315-KH Transmitter 315MHz
TXE-418-KH Transmitter 418MHz
TXE-433-KH Transmitter 433MHz
RXD-315-KH Receiver 315MHz
RXD-418-KH Receiver 418MHz
RXD-433-KH Receiver 433MHz
EVAL-***-KH Basic Evaluation Kit
*** = 315, 418 (Standard), 433.92MHz.
Transmitters are supplied in tubes of 20 pcs.

ORDERING INFORMATION

TXE-315-KH
TXE-418-KH
TXE-433-KH

0.630"

RF TRANSMITTER/ENCODER

0.180"

1.220"

TXE-418-KH

LOT 2000

Page 3

Page 2

ELECTRICAL SPECIFICATIONS

*CAUTION*

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.

1. Current draw with 50% mark / space ratio.

2. Into a 50Ω load.

3. With 430Ω resistor on LADJ.

4. Characterized, but not tested.

Notes

Table 1: KH Series Transmitter Electrical Specifications

Parameter Designation Min. Typical Max. Units Notes

POWER SUPPLY

Operating Voltage V

CC

2.7 – 5.2 VDC –

Supply Current I

CC

– 1.5 – mA 1,4

Power-Down Current I

PDN

– 1.0 – µA –

TRANSMITTER SECTION

Transmit Frequency Range: F

C

TXE-315-KH – 315 – MHz –

TXE-418-KH – 418 – MHz –

TXE-433-KH – 433.92 – MHz –

Center Frequency Accuracy – -75 – +75 kHz –

Output Power P

O

-4 +2 +4 dBm 2,3

Harmonic Emissions: P

H

TXE-315-KH -40 – – dBc –

TXE-418-KH -40 – – dBc –

TXE-433-KH -45 – – dBc –

ANTENNA PORT

RF Output Impedance R

OUT

–50–Ω 4

ENCODER SECTION

Data Length – – 26 bits 3x – – –

Average Data Duty Cycle – – 50% – – 4

Encoder Oscillator F

ENC

– 70 – kHz 4

Data Input:

Logic Low – 0.0 – 0.2 x V

CC

VDC 4

Logic High V

CC

x 0.8 – V

CC

VDC 4

Input Sink Current – 0.6 1.0 1.2 mA 4

ENVIRONMENTAL

Operating Temperature Range – -30 – +70

°C4

ABSOLUTE MAXIMUM RATINGS

Supply Voltage V

CC

-0.3 to +6.0 VDC

Any Input or Output Pin -0.3 to V

CC

VDC
Operating Temperature -30 to +70 °C
Storage Temperature -45 to +85 °C
Soldering Temperature +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.

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.

Figure 2: Test / Basic Application Circuit

TYPICAL PERFORMANCE GRAPHS

Figure 3: Supply Current vs. Supply Voltage Figure 4: Output Power vs. Supply Voltage

Figure 5: Output Power vs. LADJ Resistor

3VDC

VCC

ANT
GND

24

23

A9

22

A8

21

A7

20

A6

19

A5

18

A4

17

A3

16

A2

15

A1

14

A0

13

1

GND/LVL

2

D0
D1

3
4

GND

5

VCC

6

TE
D2

7
8

D3
D4

9

D5

10

D6

11

D7

12

12
11
10

9

8
7
6
5
4
3
2

Supply Current (mA)

1
0

With LADJ tied to ground

With 430Ω resistor on LADJ

2.5

3.0

3.5

4.0 4.5

5.0

Supply Voltage (V)

+8

With LADJ tied to ground

+7
+6
+5
+4
+3
+2
+1

0

-1

-2

-3

-4

-5

-6

Output Power Into 50 ohms (dBm)

-7

With 430Ω resistor on LADJ

2.5

3.0

3.5

Supply Voltage (V)

4.0 4.5

5.0

+8

+7

+6

+5

+4

+3

+2

+1

0

-1

Output Power (dBm)

-2

-3

-4

51 100 150 200 240 300 360 430 510 560 620 680 750 820 910 1.1K

5V

3V

LADJ Pin Resistor Value (Ω)

Page 5Page 4

PIN ASSIGNMENTS

Figure 6: KH Series Transmitter Pinout (Top View)

Pin # Name Description

1 GND / LADJ

Level Adjust. This line can be used to adjust the output

power level of the transmitter. Connecting to GND will give

the highest output, while placing a resistor to GND will

lower the output level.

2, 3,
7-12

D0 - D1

Data Input Lines. When TE goes high, the module will
encode the state of these lines for transmission. Upon

receipt of a valid transmission, the receiver / decoder will

replicate these lines on its output lines.

4 GND Analog Ground

5

V

CC

Supply Voltage

6 TE

Transmit Enable Line. When this line goes high, the

module will encode the states of the address and data lines

into a packet and transmit the packet three times.

13-22 A0-A9

Address Lines. The state of these lines must match the

state of the receiver’s address lines in order for a

transmission to be accepted.

23 GND Analog Ground

24 ANT 50-ohm RF Output

PIN DESCRIPTIONS

MODULE DESCRIPTION

The KH Series transmitter / encoder module combines a high-performance
Surface Acoustic Wave (SAW) based transmitter with an on-board encoder.
When combined with a Linx KH Series receiver / decoder, a highly reliable RF
link capable of transferring control or command data over line-of-sight distances
in excess of 300 feet is formed. The module accepts up to 8 parallel inputs, such
as switches or contact closures, and provides ten tri-state address lines for
security and creation of 59,049 (310) unique transmitter / receiver relationships.
The KH’s compact surface-mount package integrates easily into existing designs
and is friendly to hand production or automated assembly.

THEORY OF OPERATION

The KH Series transmitter operation is straightforward. When the Transmit
Enable (TE) line is taken high, the on-board encoder IC is activated. The encoder
detects the logic states of the data and address lines. These states are formatted
into a 3-word transmission, which continues until the TE line is taken low. The
encoder creates a serial data packet that is used to modulate the transmitter.

The transmitter section is based on a simple, but highly-optimized, architecture
that achieves a high fundamental output power with low harmonic content. This
ensures that most approval standards can be met without external filter
components. The KH Series transmitter is exceptionally stable over variations in
time, temperature, and physical shock as a result of the precision SAW device
that is incorporated as the frequency reference.

The transmitted signal may be received by any Linx KH Series receiver / decoder
module or Linx LC or LR Series receiver combined with the appropriate decoder
IC. Once data is received, it is decoded using a decoder IC or custom
microcontroller. The transmitted address bits are checked against the address
settings of the receiving device. If a match is confirmed, the decoder’s outputs
are set to replicate the transmitter’s inputs.

Figure 7: KH Series Transmitter Block Diagram

LADJ/GND

1

D0

2

D1 A9

3

GND

4

VCC

5

TE

6

D2

7
817

D3

9

D4

10

D5

11

D6 A1

12 13

ANT

GND

A8
A7
A6

A5
A4
A3
A2

A0D7

24
23
22
21
20
19

18

16
15
14

Address Inputs

A0-A9

OSC

50Ω RF OUT

(ANT)

Keyed Output

SAW

Oscillator

TX Enable

Sync

Divider

Counter

Parallel

Inputs

D0-D7

GATE

TRI-Detect

Output Isolation
& Filter

RF Amplifier

Buffer

RF STAGE ENCODER STAGE

Page 7Page 6

POWER SUPPLY REQUIREMENTS

The module does not have an internal voltage
regulator; therefore it requires a clean, well-regulated
power source. While it is preferable to power the unit
from a battery, it can also be operated from a power
supply as long as noise is less than 20mV. Power
supply noise can affect the transmitter modulation;
therefore, providing a clean power supply for the
module should be a high priority during design.

A 10Ω resistor in series with the supply followed by a
10µF tantalum capacitor from VCCto 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.

DATA INPUTS

When the Transmit Enable (TE) line goes high, the states of the eight data input
lines are recorded and encoded for transmission. The data lines are tri-state,
which means that they can be high, low, or floating, though the decoder will
interpret the floating state as a low. This feature means that the data lines do not
require pull-up or pull-down resistors. The states of the data lines can be set by
switches, jumpers, microcontrollers, or hardwired on the PCB.

The encoder will send the states of the address and data lines three times. If the
TE line is still high, it will begin the cycle again. This means that the states of the
data lines are refreshed with each cycle, so the data lines can be changed
without having to pull TE low. There can be up to a 150mS lag in response as
the transmitter finishes one cycle then refreshes and starts over.

ENABLING TRANSMISSION

The module’s Transmit Enable (TE) line controls transmission status. When
taken high, the module initiates transmission, which continues until the line is
pulled low or power to the module is removed. In some cases this line will be
wired permanently to V

CC

and transmission controlled by switching VCCto the

module. This is particularly useful in applications where the module powers up
and sends a transmission only when a button is pressed on the remote.

USING LADJ

The LADJ line allows the transmitter’s output power to be easily adjusted for
range control, lower power consumption, or to meet legal requirements. This is
done by placing a resistor between GND and LADJ. When LADJ is connected
directly to GND, the output power will be at its maximum. Placing a resistor will
lower the output power by up to 7dB, as shown on Page 3 of this data guide.

This is very useful during FCC testing to compensate for antenna gain or other
product-specific issues that may cause the output power to exceed legal limits.
A variable resistor can be used so that the test lab can precicely adjust the output
power to the maximun level allowed by law. The resistor’s value can be noted
and a fixed resistor substituted for final testing. Even in designs where
attenuation is not anticipated, it is a good idea to place a resistor pad connected
to LADJ and GND so that it can be used if needed.

Figure 10: Supply Filter

ENCODER OPERATION

The KH Series transmitter internally utilizes
the HT640 encoder from Holtek. The
encoder begins a three-word transmission
cycle when the Transmission Enable line
(TE) is pulled high. This cycle will repeat
itself for as long as the TE line is held high.
Once TE falls low, the encoder output
completes its final cycle and then stops as
shown in the Encoder / Decoder Timing
diagram. When a transmission enable signal
is applied, the encoder scans and transmits
the status of the 10 bits of the address code
and the 8 bits of the data serially in the order
A0 to A9, D0 to D7.

The status of each address / data pin can be
individually preset to logic high, low, or
floating. The floating state on the data input
is interpreted as logic low by the decoders
since the decoder output only has two
states. The address pins are usually set to
transmit particular security codes by DIP
switches or PCB wiring, while the data is
selected using push buttons or electronic
switches. The floating state allows the KH transmitter to be used without pull-up
or pull-down resistors on the data and address input lines.

SETTING THE TRANSMITTER ADDRESS

The module provides ten tri-state address lines. This allows for the formation of
up to 59,049 (3

10

) unique transmitter-receiver relationships. Tri-state means that
the address lines have three distinct states: high, low, or floating. These pins
may be hardwired or configured via a microprocessor, DIP switch, or jumpers.
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.

Figure 8: Encoder Flowchart

Check

Check

< 1 Word

3 Words

Transmitted Continuously

3 Words

1/2 Clock Time

Decoder

Data Out

Decoder VT

Encoder

Data Out

Encoder

Transmit

Enable

1/2 Clock Time

2 Words

214 Clocks

214 Clocks

Figure 9: Encoder / Decoder Timing Diagram

No

No

Power On

Standby Mode

Transmission

Enabled?

Yes

3 Data Words

Transmitted

Transmission
Still Enabled?

Yes

3 Data Words

Transmitted

Continuously

Vcc IN

10Ω

Vcc TO
MODULE

+

10μF