AN-00100 [ETC]

Transceiver Module;


型号：	AN-00100
厂家：	ETC
描述：	Transceiver Module
文件：	总23页 (文件大小：2372K)
中文：	中文翻译
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NT Series

Transceiver Module

Data Guide

Warning: Linx radio frequency ("RF") products may be

Table Of Contents

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.

1 Description

1 Features

2 Ordering Information

2 Absolute Maximum Ratings

3 Electrical Speciﬁcations

6 Typical Performance Graphs

11 Module Description

11 Theory of Operation

12 Pin Assignments

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.

12 Pin Descriptions

14 Sending Data

14 The Data Input

15 The Data Output

15 Using the RSSI Line

16 Using the T/R_SEL Input

16 Using the Low Power Features

17 Using the READY Output

17 Using the LVL_ADJ Line

18 Baud Band Selection

19 Channel Selection

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, but the developer can implement

frequency agility with a microcontroller and the example code in Linx

Reference Guide RG-00101.

20 European Transmission Rules

23 Typical Applications

24 Power Supply Requirements

24 Antenna Considerations

25 Protocol Guidelines

26 Interference Considerations

27 Pad Layout

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.

27 Board Layout Guidelines

29 Microstrip Details

30 Production Guidelines

30 Hand Assembly

30 Automated Assembly

NT Series Transceiver Module

Data Guide

32 General Antenna Rules

34 Common Antenna Styles

36 Regulatory Considerations

38 Achieving a Successful RF Implementation

39 Helpful Application Notes From Linx

1.150"

Description

The NT Series transceiver module is designed

for bi-directional wireless data transfer. The

868MHz version is suitable for European

operation and the 900MHz version is suitable

for North and South America. The modules

have an outstanding range of up to 3,000 feet

(914 meters, line of sight). Low power states

0.630"

0.131"

NT Series Transceiver

TRM-900-NT

Figure 1: Package Dimensions

optimize current consumption for battery-powered devices.

The modules have two interfaces for data transfer. The ﬁrst uses a standard

Universal Asynchronous Receiver Transmitter (UART) with a simple built-in

protocol that supports data rates of 9.6kbps or 56kbps (see Reference

Guide 00102). The other option is a transparent interface that bypasses the

protocol engine and directly modulates the RF carrier. This supports data

rates of up to 300kbps.

The basic conﬁguration settings are done in hardware through the logic

state of several pins on the module. Optionally the UART interface can be

used for software conﬁguration, also giving access to additional features.

The modules are capable of generating +12.5dBm into 50-ohms and have

a typical sensitivity of −113dBm. Housed in a compact reﬂow-compatible

SMD package, the transceivers require no external RF components except

an antenna, greatly simpliﬁying integration and lowering assembly costs.

Features

•ꢀ Long range

•ꢀ Power saving options

•ꢀ Low cost

(POWER_DOWN, STANDBY)

•ꢀ Adjustable output power level

•ꢀ No external RF components

required

•ꢀ Wide temperature range

•ꢀ Compact surface mount package

•ꢀ Low power consumption

•ꢀ No programming required

•ꢀ 8 parallel selectable channels

•ꢀ Transparent data transfer

•ꢀ Data rates up to 300kbps

•ꢀ RSSI and READY output signals •ꢀ No production tuning required

–

Revised 2/9/2018

Ordering Information

Electrical Speciﬁcations

NT Series Transceiver Speciﬁcations

Ordering Information

Parameter

Symbol

Min.

Typ.

Max.

Units Notes

Part Number

TRM-868-NT

TRM-900-NT

MDEV-868-NT

MDEV-900-NT

Description

Power Supply

868MHz NT Series Transceiver

Operating Voltage

TX Supply Current

At +12.5dBm

V_CC

2.5

5.5

VDC

900MHz NT Series Transceiver

l_CCTX

868MHz NT Series Master Development System

900MHz NT Series Master Development System

µA

1,2

At 0dBm

Transceivers are supplied in tubes of 18 pcs.

RX Supply Current

Power-Down Current

Standby Current

RF Section

l_CCRX

l_PDN

l_STD

Figure 2: Ordering Information

1.0

2.5

1.4

Absolute Maximum Ratings

Center Frequency Range

TRM-868-NT

F_C

Absolute Maximum Ratings

Supply Voltage V_cc

863

902

–5

870

928

MHz

kHz

−0.3

+5.5

VDC

dBm

ºC

TRM-900-NT

Any Input or Output Pin

RF Input

V_CC+ 0.3

Center Frequency Accuracy

Number of Channels

TRM-868-NT

Operating Temperature

Storage Temperature

−40

−55

+85

8/68

8/101

250

3, 10

3,10

+125

ºC

TRM-900-NT

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.

Channel Spacing

Data Rate

kHz

Baud Band = 1

Baud Band = 2

Baud Band = 3

Baud Band = 4

Receiver Section

IF Frequency

19.2

kbps

Figure 3: Absolute Maximum Ratings

19.2

160

300

160

F_IF

Baud Band = 1

Baud Band = 2

Baud Band = 3

Baud Band = 4

Spurious Emissions

Receiver Sensitivity

Baud Band = 1

Baud Band = 2

Baud Band = 3

Baud Band = 4

200

300

kHz

dBm

4,11

−62

−111

−108

−104

−100

−113

−110

−106

−102

dBm

5,11

–

NT Series Transceiver Speciﬁcations

Parameter

Symbol

Min.

Typ.

Max.

Units Notes

Parameter

Logic Low

Logic High

POWER_DOWN

Logic Low

Logic High

Input

Symbol

V_OL

Min.

Typ.

0.3

Max.

Units Notes

VDC

RSSI

0.4

Dynamic Range

Transmitter Section

Output Power

V_OH

V_CC–0.4

0.5*V_CC

VDC

P_O

P_H

−15.5

+12.5

–36

dBm

V_I

0.8

5.5

VDC

Output Power Control

Range

V_IH

Harmonic Emissions

Frequency Deviation

Baud Band = 1

Baud Band = 2

Baud Band = 3

Baud Band = 4

Antenna Port

−42

dBc

Logic Low

Logic High

Output

V_IL

V_IH

0.8

5.5

VDC

kHz

3,11

Logic Low

Logic High

V_OL

V_OH

0.6

V_CC

VDC

V_CC–0.7

120

1. Measured at 3.3V V_CC

2. Measured at 25ºC

9. Time starts when supply voltage

reaches V_CCminimum

3. Guaranteed by design

10. 68 / 101 channels through the serial

interface

RF In/Out Impedance

Environmental

R_IN

4. Characterized but not tested

5. At the band’s low data rate; BER=10^–311. Baud Band is a user selected setting

6. Into a 50-ohm load

that determines ﬁlter settings, max data

rate, receiver sensitivity and transmitter

frequency deviation. See Baud Band

Selection for more details.

Operating Temp. Range

Storage Temp. Range

Timing

−40

−55

+85

ºC

7. P_O=+12.5dBm (max output power)

8. Module is not busy performing other

tasks

+125

Receiver Turn-On Time

Via V_CC

Figure 4: Electrical Speciﬁcations

5.0

0.6

4,9

4,8

Via Power Down

Via Standby

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.

Transmitter Turn-On Time

Via V_CC

5.0

0.7

0.6

4.0

4,9

4,8

Via Power Down

Via Standby

TX to RX Switch Time

RX to TX Switch Time

Channel Change Time

Baud Band Change Time

Interface Section

DATA_IN

Logic Low

V_IL

V_IH

0.3

0.2*V_CC

VDC

Logic High

0.7*V_CC

0.5*V_CC

DATA_OUT

–

Typical Performance Graphs

+85°C

-40°C

+25°C

-2

-7

-12

-17

2.5

3.5

4.5

5.5

150

300

450

600

750

900

Supply Voltage (V)

LVL_ADJ Resistance (kΩ)

Figure 8: NT Series Transceiver TX Current Consumption vs. Supply Voltage at +12.5dBm

Figure 5: NT Series Transceiver Output Power vs. LVL_ADJ Resistance

+85°C

+25°C

-40°C

+25°C

+85°C

-40°C

2.5

3.5

4.5

5.5

-20

Supply Voltage (V)

-15

-10

-5

TX Output Power (dBm)

Figure 9: NT Series Transceiver TX Current Consumption vs. Supply Voltage at 0dBm

Figure 6: NT Series Transceiver Current Consumption vs. Transmitter Output Power at 3.3V

+85°C

-40°C

+25°C

+85°C

-40°C

-20

2.5

3.5

4.5

5.5

Supply Voltage (V)

-15

-10

-5

TX Output Power (dBm)

Figure 10: NT Series Transceiver RX Current Consumption vs. Supply Voltage

Figure 7: NT Series Transceiver Current Consumption vs. Transmitter Output Power at 5.5V

–

1. 2.00V/div

2. 2.00V/div

570µs

STANDBY

READY

500µs/div

Figure 14: NT Series Transceiver Turn-On Time from Standby

1. 2.00V/div 2. 2.00V/div

Figure 11: NT Series Transceiver RSSI Voltage vs. Input Power

1. 2.00V/div

2. 2.00V/div

630µs

4.67ms

STANDBY

VCC

READY

500µs/div

Figure 15: NT Series Transceiver Transmitter Turn-On Time from Standby

1. 2.00V/div 2. 2.00V/div

2ms/div

Figure 12: NT Series Transceiver Receiver Turn-On Time from VCC

1. 2.00V/div

2. 2.00V/div

690µs

4.71ms

T/R_SEL

VCC

READY

500µs/div

Figure 16: NT Series Transceiver TX to RX Change Time

2ms/div

Figure 13: NT Series Transceiver Turn-On Time from VCC

–

1. 2.00V/div

2. 2.00V/div

Module Description

680µs

The NT Series transceiver (Figure 20) is a low-cost, high-performance

synthesized FSK transceiver capable of transmitting and receiving serial

data at up to 300kbps. Its exceptional sensitivity results in outstanding

range performance. The module’s compact surface-mount package is

friendly to automated or hand production. NT Series modules are capable

of meeting the regulatory requirements of many domestic and international

applications.

T/R_SEL

READY

FSK

LNA

INTERFACE /

VOLTAGE

TRANSLATION

DEMOD

RSSI/

GPIO /

INTERFACE

8-BIT

ADC

PROCESSOR

LOGAMP

CDR

AFC

AGC

500µs/div

Figure 17: NT Series Transceiver RX to TX Change Time

1. 2.00V/div 2. 2.00V/div

ANTENNA

LOOP

CHARGE

26MHz

VCC

LDO

DIVIDER

PFD

FILTER

PUMP

OSC

DIVIDER

PA RAMP

PROFILE

PDN

f_DEV

GAUSSIAN

FILTER

Σ-Δ

0.53ms

MODULATOR

Figure 20: NT Series Transceiver Block Diagram

CHN_SELx

Theory of Operation

The NT Series transceiver is a highly integrated FSK transceiver designed

for operation in the 863–870MHz and 902–928MHz frequency bands.

The RF synthesizer contains a VCO and a low-noise fractional-N PLL. The

VCO operates at two times the fundamental frequency to reduce spurious

emissions. The receive and transmit synthesizers are integrated, enabling

them to be automatically conﬁgured to achieve optimum phase noise,

modulation quality and settling time.

READY

500µs/div

Figure 18: NT Series Transceiver Channel Change Time

1. 2.00V/div 2. 2.00V/div

The transmitter output power is programmable from −15.5dBm to

+12.5dBm with automatic PA ramping to meet transient spurious

speciﬁcations. The ramping and frequency deviation are optimized in each

of four baud bands to deliver the highest performance over a wide range of

data rates.

3.9ms

BAUDx

The receiver incorporates highly efﬁcient low-noise ampliﬁers that provide

up to −113dBm sensitivity. All of the ﬁlters are optimized to the highest

performance in each of the four baud bands. Advanced interference

blocking makes the transceiver extremely robust when in the presence of

interferers.

READY

1ms/div

Figure 19: NT Series Transceiver Baud Band Change Time

–

A low-power onboard communications processor performs the radio

control and management functions. An interface processor performs the

higher level functions and controls the serial and hardware interfaces.

This block also includes voltage translation to allow the internal circuits to

operate at a low voltage to conserve power while enabling the interface to

operate over the full external voltage. This prevents hardware damage and

communication errors due to voltage level differences.

Pin Descriptions

Pin Number

Name

Description

CHN_SEL0 ¹

CHN_SEL1 ¹

CHN_SEL2 ¹

Parallel Channel Select 0

Parallel Channel Select 1

Parallel Channel Select 2

Level Adjust. This line sets the transmitter output

power level. Pull high or leave open for the high-

est power; connect to GND through a resistor to

lower the power.

LVL_ADJ ¹

While operation is recommended from 3.3V to 5.0V, the transceiver can

operate down to 2.5V.

Ready. This line is low when the transceiver is

ready to communicate and high when it is busy.

This line can be used for hardware handshaking

on the command port.

READY

Pin Assignments

Transmit/Receive Select. Pull this line low to place

the transceiver into receive mode. Pull it high to

place it into transmit mode.

GND

GND 44

ANTENNA 43

GND 42

T/R_SEL ¹

GND

Baud Rate Select 0. This line and BAUD1 set the

over-the-air data rate and ﬁlter bandwidths.

BAUD0 ¹

BAUD1 ¹

NC 41

NC 40

GND 39

GND

Baud Rate Select 1. This line and BAUD0 set the

over-the-air data rate and ﬁlter bandwidths.

DATA_IN 38

DATA_OUT 37

NC 36

Received Signal Strength Indicator. This line

outputs an analog voltage that is proportional to

the strength of the received signal. Updated once

a second.

TRPT/PKT

RSSI

10 CHN_SEL0

11 GND

NC 35

GND 34

Power Down. Pulling this line low places the

module into a low-power state. The module will

not be functional in this state. Pull high for normal

operation.

12 CHN_SEL1

13 CHN_SEL2

14 LVL_ADJ

NC 33

NC 32

CMD_DATA_BAUD 31

CMD_DATA_TYPE 30

CMD_DATA_OUT 29

GND 28

POWER_DOWN

READY

VCC

Supply Voltage

16 NC

Standby. Pull this line high or leave ﬂoating to put

the module into low-power standby mode. Pull to

GND for normal operation.

17 GND

STANDBY ¹

18 T/R_SEL

19 BAUD0

20 BAUD1

21 RSSI

22 GND

CMD_DATA_IN 27

STANDBY 26

VCC 25

CMD_DATA_IN ²

Command Data In. Pull high for normal operation.

POWER_DOWN 24

Command Data Out. Do not connect for normal

operation.

CMD_DATA_OUT ²

GND

Command Data Type. Pull low for normal

operation.

CMD_DATA_TYPE ²

CMD_DATA_BAUD ²

DATA_OUT

Figure 21: NT Series Transceiver Pinout (Top View)

Pin Descriptions

Command Data Baud. Pull low for normal

operation.

Received Data Output. This line outputs the

demodulated digital data.

Pin Descriptions

Pin Number

Name

Description

Transmit Data Input. This line accepts the data to

be transmitted.

DATA_IN

1, 3, 6, 11, 17,

22, 23, 28, 34,

39, 42, 44

GND

Ground

ANTENNA

50-ohm RF Antenna Port

1. These lines have an internal 100kΩ pull-up resistor

2. Contact Linx for more information

2, 4, 5, 7, 8,

16, 32, 33, 35,

36, 40, 41

No Connection

TRPT / PKT ^1,2

Transparent/Packet Data Select. Pull high or ﬂoat.

Figure 22: NT Series Transceiver Pin Descriptions

–

Sending Data

The Data Output

The NT Series transceiver module has two interfaces for sending data. One

interface uses a UART to pass data in and out of the module. The modules

put the data into a packet and take care of the transmission, reception and

error check. This is a very low level over-the-air protocol and does not have

any networking capabilites built in, but these capabilities can be added in

a microcontroller outside the module. This interface and the protocol are

detailed in RG-101 (NT Series Command Data Interface Reference Guide)

and RG-102 (NT Series Transceiver Wireless UART Reference Guide).

Receive Mode is enabled when the T/R_SEL line is logic low. The

demodulated data is output on the DATA_OUT line. Like the DATA_IN line,

this line may be directly connected to virtually any digital peripheral such as

a microcontroller or decoder.

It is important to note that the transceiver does not provide squelching of

the DATA_OUT line when in receive mode. This means that in the absence

of a valid transmission, the DATA_OUT line switches randomly. This noise

can be handled in software by implementing a noise tolerant protocol as

described in Linx Application Note AN-00160 (Figure 44).

This guide details the modules transparent interface. Through this interface

the module does not encode or packetize the data in any manner. The

data present on the DATA_IN line is used to modulate the transmitter. The

received data is output on the DATA_OUT line and the transmit/receive

state is controlled with the T/R_SEL line. This transparency gives the

designer great freedom in software and protocol development, allowing the

creation of unique and proprietary data structures. This mode also allows

the use of PWM and non-standard baud rate data.

Using the RSSI Line

The receiver’s Received Signal Strength Indicator (RSSI) line serves a

variety of functions. This line has a dynamic range of 64dB and outputs a

voltage proportional to the incoming signal strength. The RSSI Voltage vs.

Input Power graph in the Typical Performance Graphs section shows the

relationship between the RSSI voltage and the incoming signal power. This

voltage is updated once a second. This line has a high impedance and an

external buffer may be required for some applications.

The READY line outputs a logic low when the module is ready for use and

logic high when it is busy. It can be used as hardware ﬂow control to send

streaming data and ensure that data is not missed.

It should be noted that the RSSI levels and dynamic range will vary from

part to part. It is also important to remember that RSSI output indicates

the strength of any in-band RF energy and not necessarily just that from

the intended transmitter; therefore, it should be used only to qualify the

presence and level of a signal. Using RSSI to determine distance or data

validity is not recommended.

The Data Input

Transmit Mode is enabled when the T/R_SEL line is logic high. The data

on the DATA_IN line is transmitted over the air. The DATA_IN line may be

directly connected to virtually any digital peripheral, including microcon-

trollers and encoders. It can be used with any data that transitions from 0V

to V_CCpeak amplitude within the speciﬁed data rate range of the selected

baud band. While it is possible to send data at higher rates, the internal

ﬁlters will cause severe roll-off and attenuation.

The RSSI output can be utilized during testing or even as a product feature

to assess interference and channel quality by looking at the RSSI level

with all intended transmitters shut off. The RSSI output can also be used

in direction-ﬁnding applications, although there are many potential perils to

consider in such systems. Finally, it can be used to save system power by

“waking up” external circuitry when a transmission is received or crosses a

certain threshold. The RSSI output feature adds tremendous versatility for

the creative designer.

Many RF products require a ﬁxed data rate or place tight constraints on

the mark/space ratio of the data being sent. The transceiver architecture

eliminates such considerations and allows virtually any signal, including

PWM, Manchester, and NRZ data, to be sent at rates from 1kbps to

300kbps.

–

Using the T/R_SEL Input

Using the READY Output

The transmit/receive select (T/R_SEL) line is used to switch the transceiver

between transmit and receive mode. If it is pulled low, the transceiver exits

transmit mode and enters receive mode. Alternatively, if the line is pulled

high, the transceiver exits receive mode and enters transmit mode. The

READY output switches high during the change and returns low when the

module is ready to receive or transmit data. None of the other operating

modes are affected by the change. The data rate and channel settings

remain as set.

The Ready (READY) line can be used to monitor the status of the module.

It is logic high while the transceiver is busy and logic low when the

transceiver is ready to transmit or receive data. This allows the line to be

used as hardware ﬂow control. It is logic high when in Standby, but is logic

low in Power Down since the entire module is off.

Using the LVL_ADJ Line

The Level Adjust (LVL_ADJ) line allows the transceiver’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 to ground on LVL_ADJ to

form a voltage divider with an internal 100kΩ resistor. When the transceiver

powers up, the voltage on this line is measured and the output power

level is set accordingly. When LVL_ADJ is connected to V_CCor ﬂoating, the

output power and current consumption are the highest. When connected

to ground, the output power and current are the lowest. The power is

digitally controlled in 58 steps providing approximately 0.5dB per step. See

the Typical Performance Graphs section (Figures 5–19) for a graph of the

output power vs. LVL_ADJ resistance.

Using the Low Power Features

The Power Down (POWER_DOWN) line can be used to completely power

down the transceiver module without the need for an external switch.

This line allows easy control of the transceiver power state from external

components, such as a microcontroller. The module is not functional while

in power down mode.

Similar to the POWER_DOWN line, the Standby (STANDBY) line can be

used to put the transceiver into a low-power sleep mode. This line has an

internal pull-up, so when it is held high or left ﬂoating, the transceiver enters

a low power (2.6mA) state. When the STANDBY line is pulled to ground,

the module is fully active. During Standby, all operating modes are

deactivated. The READY output is high during standby.

Warning: The LVL_ADJ line uses a resistor divider to create

a voltage that determines the output power. Any additional current

sourcing or sinking can change this voltage and result in a different

power level. The power level should be checked to conﬁrm that it is set

as expected.

Standby has a higher current consumption than Power Down but a

faster wake-up time. By periodically activating the transceiver, sending

data, then powering down or entering standby, the transceiver’s average

current consumption can be greatly reduced, saving power in

battery-operated applications.

This line is very useful during regulatory testing to compensate for antenna

gain or other product-speciﬁc issues that may cause the output power to

exceed legal limits. A variable resistor to ground can be temporarily used

so that the test lab can precisely adjust the output power to the maximum

level allowed by law. The variable 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 resistor pads connected to

LVL_ADJ and ground so that it can be used if needed. Figure 23 on the

following page shows the 1% tolerance resistor value that is needed to

activate each power level.

Warning: Pulling any of the module inputs high while in

Power Down can partially activate the module, increasing current

consumption and potentially placing it into an indeterminate state that

could lead to unpredictable operation. Pull all inputs low before pulling

POWER_DOWN low to prevent this issue. Lines that may be hardwired

(for example, the BAUD lines) can be connected to the POWER_DOWN

line so that they are lowered when POWER_DOWN is lowered.

–

Power Level vs. Resistor Value

Baud Band Selection

Baud Rate IF Bandwidth Receiver Sensitivity

Power

Resistor Level (dB^Om) Resistor Level (dB^Om) Resistor

Baud Band BAUD1 BAUD0

Power

Level

(dB^Om)

(kbps)

(kHz)

100

150

200

300

(dBm)

−113

−110

−106

−102

Value

Open

750k

649k

576k

510k

453k

412k

347k

340k

316k

287k

267k

243k

226k

210k

200k

182k

174k

165k

Value

154k

143k

133k

127k

118k

111k

105k

97.6k

91k

value

44.2k

41.2k

37.4k

34.8k

32.4k

29.4k

26.7k

24.3k

22k

1 to 19.2

19.2 to 80

80 to 160

160 to 300

12.22

12.12

12.14

11.86

11.85

9.58

9.78

8.94

8.33

8.02

7.42

6.99

6.72

6.33

5.80

5.38

4.83

4.33

4.05

3.49

3.11

−5.47

−5.78

−6.12

−6.72

−7.09

−7.52

−7.91

−8.36

−8.83

−9.39

−9.13

−9.68

−10.23

−10.86

−11.50

−12.23

−13.04

−13.98

−14.59

−15.78

2.77

2.12

1.65

Figure 24: NT Series Transceiver Baud Band Selection

1.16

Channel Selection

0.81

The transceiver allows for setting the channel frequency with the

CHN_SEL0, CHN_SEL1 and CHN_SEL2 lines in a parallel manner. The

logic states of the three lines select from among eight channels. This allows

the channel to be set by DIP switches, microcontroller lines or hardwired.

The 868MHz channels are shown in Figure 25 and the 900MHz channels

are shown in Figure 26.

0.38

−0.18

−0.66

−0.93

−1.46

−1.84

−2.39

−2.83

−3.27

−3.79

−4.30

−4.85

86.6k

80.6k

76.8k

71.5k

66.5k

62k

19.6k

17.4k

15.4k

13.3k

11.3k

9.53k

7.5k

868MHz Channel Selection

CHN_SEL2

CHN_SEL1

CHN_SEL0

CHANNEL

FREQUENCY

863.15

57.6k

54.9k

51k

864.15

5.76k

4.02k

2.32k

750

865.15

866.15

47k

868.35

868.95

Figure 23: NT Series Transceiver Power Level vs. Resistor Value

869.55

869.85

Baud Band Selection

There are two baud select lines (BAUD0 and BAUD1) that conﬁgure the

transceiver for the desired over-the-air data rate. The two baud select lines

choose among four baud bands, or ranges of data rate and IF bandwidth,

as shown in Figure 24.

Figure 25: NT Series Transceiver 868MHz Channel Selection

Setting the baud band appropriately for the desired baud rate conﬁgures

the internal ﬁlters and circuitry for optimal performance at that rate. Data

can be sent in at a lower rate than speciﬁed for the band, but the sensitivity,

and therefore range, will not be as good as in a lower setting. Data can

also be sent in faster than speciﬁed by the band, but the internal ﬁlters will

cause distortion of the data stream and range will be signiﬁcantly reduced.

–

900MHz Channel Selection

868MHz Channel Selection

CHN_SEL2

CHN_SEL1

CHN_SEL0

CHANNEL

FREQUENCY

903.37

Channel Frequency

D.C.

Channel Frequency

D.C.

0.10%

863.15

863.25

863.35

863.45

863.55

863.65

863.75

863.85

863.95

864.05

864.15

864.25

864.35

864.45

864.55

864.65

864.75

864.85

864.95

865.05

865.15

865.25

865.35

865.45

865.55

865.65

865.75

865.85

865.95

866.05

866.15

866.25

866.35

866.45

0.10%

866.55

866.65

866.75

866.85

866.95

867.05

867.15

867.25

867.35

867.45

867.55

867.65

867.75

867.85

867.95

868.05

868.15

868.25

868.35

868.45

868.55

868.65

868.75

868.85

868.95

869.05

869.15

869.25

869.35

869.45

869.55

869.75

869.85

869.95

906.37

907.87

909.37

912.37

915.37

919.87

921.37

Figure 26: NT Series Transceiver 900MHz Channel Selection

European Transmission Rules

While the FCC does not have any requirements other than power

and harmonic levels for the 900MHz band, European rules are more

complicated. The 863 to 870MHz band is subdivided into other bands that

are designated for speciﬁc applications. These sub bands can be used for

generic devices provided they meet one of two requirements.

The ﬁrst requirement is duty cycle, which is deﬁned as the amount of time

the transmitter is on per hour. The duty cycle is different for the different

bands and ranges from 0.1% to 10%.

0.10%

10%

The other option is that the transmitter implement Listen-Before-Talk (LBT)

optionally combined with Adaptive Frequency Agility (AFA). This basically

means that the transmitter will listen to a channel to be sure that it is clear

before transmitting (LBT). If the channel is occupied by another transmitter,

then it will wait until the channel is clear or change to another channel to

transmit its data (AFA).

The NT Series does not implement LBT or AFA, but these features can

be added to a microcontroller outside the module. Implementing these

eliminates the need to track the transmit time to ensure compliance with

the duty cycle limits.

10%

None/ 1%*

None / 1%*

Figure 27 lists the 868MHz channels and their duty cycle requirements if

LBT is not implemented. It is recommended that the designer review ETSI

EN 300 220-1 for the full requirements.

* No duty cycle limit at 5mW max power, 1% limit at 25mW max power.

Dark Gray = Hardware Selectable Channels

Figure 27: NT Series Transceiver 868MHz Serial Channels and Duty Cycle Requirements

–

Figure 28 shows the 900MHz channels avaiable through the module's

serial Command Data Interface.

Typical Applications

Figure 29 shows a circuit using the NT Series transceiver.

NT Series Transceiver 900MHz Serial Channels

GND

Channel Frequecy Channel Frequecy Channel Frequecy Channel Frequecy

ANTENNA

902.62

902.87

903.12

903.37

903.62

903.87

904.12

904.37

904.62

904.87

905.12

905.37

905.62

905.87

906.12

906.37

906.62

906.87

907.12

907.37

907.62

907.87

908.12

908.37

908.62

908.87

909.12

909.37

909.62

909.87

910.12

910.37

910.62

910.87

911.12

911.37

911.62

911.87

912.12

912.37

912.62

912.87

913.12

913.37

913.62

913.87

914.12

914.37

914.62

914.87

915.12

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

100

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

GND

VCC

GND

DATA_IN

GND

GPIO

DATA_OUT

TRPT/PKT

CHN_SEL

GND

CHN_SEL

LVL_ADJ

READY

GND

CMD_DATA_BAUD

CMD_DATA_TYPE

CMD_DATA_OUT

GND

VCC

T/R_SEL

BAUD0

BAUD1

RSSI

CMD_DATA_IN

STANDBY

VCC

GND

VCC

GND

POWER_DOWN

GND

Figure 29: NT Series Transceiver Typical Application

The channel select lines are controlled with a DIP switch, so changing the

switches changes the channel. DATA_IN and DATA_OUT are connected to

GPIOs on a microcontroller that generates and decodes the over-the-air

data. READY and RSSI are monitored by the microcontroller and T/R_SEL,

POWER_DOWN and STANDBY are controlled by the microcontroller.

The BAUD lines are tied low, placing the module into a single baud band

(19.2kbps). This circuit allows the microcontroller to monitor and control the

power state of the module while the end user manually selects the channel.

Dark Gray = Hardware Selectable Channels

Figure 28: NT Series Transceiver 900MHz Serial Channels

–

The transceiver includes a U.FL connector as well as a line for the antenna

connection. This offers the designer a great deal of ﬂexibility in antenna

selection and location within the end product. Linx offers cable assemblies

with a U.FL connector on one end and several types of standard and

FCC-compliant reverse-polarity connectors on the other end. Alternatively,

the designer may wish to use the pin and route the antenna to a PCB

mount connector or even a printed loop trace antenna. This gives the

designer the greatest ability to optimize performance and cost within the

design.

Power Supply Requirements

The transceiver incorporates a precision

low-dropout regulator which allows operation

over a wide input voltage range. Despite this

regulator, it is still important to provide a supply

that is free of noise. Power supply noise can

signiﬁcantly affect the module’s performance,

so providing a clean power supply for the

module should be a high priority during design.

Vcc TO

MODULE

10Ω

Vcc IN

10µF

Figure 30: Supply Filter

Note: Either the connector or the line can be used for the antenna, but

not both at the same time.

A 10Ω resistor in series with the supply followed by a 10µF tantalum

capacitor from V_CCto ground will help in cases where the quality of supply

power is poor (Figure 30). 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.

Protocol Guidelines

While many RF solutions impose data formatting and balancing

requirements, the transparent modes of 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 custom protocol design and interface.

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

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 see Linx

Application Note AN-00160 (Figure 47).

Figure 31: Linx Antennas

design and matching is a complex

task. Professionally designed antennas such as those from Linx (Figure

31) will help ensure maximum performance and FCC and other regulatory

compliance.

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.

Linx transmitter modules typically have an output power that is 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 LVL_ADJ line.

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.

Additional details are in Application Note AN-00500 (Figure 47).

–

Interference Considerations

Pad Layout

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.

The pad layout diagram in Figure 32 is designed to facilitate both hand and

automated assembly.

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.

Figure 32: Recommended PCB Layout

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.

Board Layout Guidelines

The module’s design makes integration straightforward; however, it is

still critical to exercise care in PCB layout. Failure to observe good layout

techniques can result in a signiﬁcant degradation of the module’s

performance. A primary layout goal is to maintain a characteristic 50-ohm

impedance throughout the path from the antenna to the module.

Grounding, ﬁltering, decoupling, routing and PCB stack-up are also

important considerations for any RF design. The following section provides

some basic design guidelines which may be helpful.

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.

During prototyping, the module should be soldered to a properly laid-out

circuit board. The use of prototyping or “perf” boards will result in poor

performance and is strongly discouraged. Likewise, the use of sockets

can have a negative impact on the performance of the module and

are discouraged.

Although technically 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

shorter useful distances for the link.

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.

When possible, separate RF and digital circuits into different PCB regions.

Make sure internal wiring is routed away from the module and antenna and

is secured to prevent displacement.

–

Do not route PCB traces directly under the module. There should not be

any copper or traces under the module on the same layer as the module,

just bare PCB. The underside of the module has traces and vias that could

short or couple to traces on the product’s circuit board.

The Pad Layout section shows a typical PCB footprint for the module.

A ground plane (as large and uninterrupted as possible) should be placed

on a lower layer of your PC board opposite the module. This plane is

essential for creating a low impedance return for ground and consistent

stripline performance.

Microstrip Details

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 high-frequency 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 and 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 FR-4

board material, the trace width would be 111 mils. The correct trace width

can be calculated for other widths and materials using the information in

Figure 33 and examples are provided in Figure 34. Software for calculating

Use care in routing the RF trace between the module and the antenna or

connector. Keep the trace as short as possible. Do not pass it under the

module or any other component. Do not route the antenna trace on

multiple PCB layers as vias will add inductance. Vias are acceptable for

tying together ground layers and component grounds and should be used

in multiples.

Each of the module’s ground pins should have short traces tying

immediately to the ground plane through a via.

microstrip lines is also available on the Linx website.

Trace

Board

Bypass caps should be low ESR ceramic types and located directly

adjacent to the pin they are serving.

Ground plane

A 50-ohm coax should be used for connection to an external antenna.

A 50-ohm transmission line, such as a microstrip, stripline or coplanar

waveguide should be used for routing RF on the PCB. The Microstrip

Details section provides additional information.

In some instances, a designer may wish to encapsulate or “pot” the

product. There are a wide variety of potting compounds with varying

dielectric properties. Since such compounds can considerably impact RF

performance and the ability to rework or service the product, it is the

responsibility of the designer to evaluate and qualify the impact and

suitability of such materials.

Figure 33: Microstrip Formulas

Example Microstrip Calculations

Width / Height

Ratio (W / d)

Effective Dielectric

Constant

Characteristic

Impedance (Ω)

Dielectric Constant

4.80

4.00

2.55

1.8

2.0

3.0

3.59

3.07

2.12

50.0

51.0

48.8

Figure 34: Example Microstrip Calculations

–

Reﬂow Temperature Proﬁle

Production Guidelines

The single most critical stage in the automated assembly process is the

reﬂow stage. The reﬂow proﬁle in Figure 37 should not be exceeded

because excessive temperatures or transport times during reﬂow will

irreparably damage the modules. Assembly personnel 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

The module is housed in a hybrid SMD package that supports hand and

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.

Hand Assembly

recommended reﬂow oven proﬁle for the modules.

Pads located on the bottom

of the module are the primary

300

Soldering Iron

Tip

Recommended RoHS Profile

Recommended Non-RoHS Profile

Max RoHS Profile

mounting surface (Figure 35).

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

255°C

250

200

150

100

235°C

217°C

Solder

185°C

180°C

PCB Pads

Castellations

125°C

Figure 35: Soldering Technique

quick hand soldering for prototyping and small volume production. 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 in Figure 36.

120

150

180

210

240

270

300

330

360

Time (Seconds)

Figure 37: Maximum Reﬂow Temperature Proﬁle

Shock During Reﬂow Transport

Since some internal module components may reﬂow along with the

Warning: Pay attention to the absolute maximum solder times.

Absolute Maximum Solder Times

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.

Hand Solder Temperature: +427ºC for 10 seconds for lead-free alloys

Reﬂow Oven: +255ºC max (see Figure 37)

Figure 36: Absolute Maximum Solder Times

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.

Automated Assembly

For high-volume assembly, the modules are generally auto-placed.

The modules have been designed to maintain compatibility with reﬂow

processing techniques; however, due to their hybrid nature, certain aspects

of the assembly process are far more critical than for other component

types. Following are brief discussions of the three primary areas where

caution must be observed.

–

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.

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.

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.

2. Optimum performance is obtained from a ¼- or ½-wave straight whip

mounted at a right angle to the ground plane (Figure 38). In many

cases, this isn’t desirable for practical or ergonomic reasons, thus,

an alternative antenna style such as a helical, loop or patch may be

utilized and the corresponding sacriﬁce in performance accepted.

6. In some applications, it is advantageous to place the module and

antenna away from the main equipment (Figure 40). 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.

OPTIMUM

NOT RECOMMENDED

USABLE

Figure 38: Ground Plane Orientation

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.

CASE

GROUND PLANE

(MAY BE NEEDED)

NUT

4. In many antenna designs, particularly ¼-wave whips, the ground plane

Figure 40: Remote Ground Plane

acts as a counterpoise, forming, in essence,

VERTICAL λ/4 GROUNDED

ANTENNA (MARCONI)

a ½-wave dipole (Figure 39). For this 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 surface area less than or equal

to the overall length of the ¼-wave radiating

element. This is often not practical due to

size and conﬁguration constraints. In these

instances, a designer must make the best use

of the area available to create as much ground

DIPOLE

ELEMENT

λ/4

GROUND

PLANE

VIRTUAL λ/4

λ/4

DIPOLE

Figure 39: Dipole Antenna

–

Loop Style

Common Antenna Styles

A loop or trace style antenna is normally printed

directly on a product’s PCB (Figure 44). 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 VSWR at the desired frequency which can cause

instability in the RF stage.

There are 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, AN-00500 and AN-00501. Linx

antennas and connectors offer outstanding performance at a low price.

Whip Style

Figure 44: Loop or Trace Antenna

A whip style antenna (Figure 41) provides

outstanding overall performance and stability.

A low-cost whip 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

Linx offers low-cost planar (Figure 45) and chip

antennas that mount directly to a product’s PCB.

These tiny antennas do not require testing and

provide excellent performance despite their small

size. They offer a preferable alternative to the often

problematic “printed” antenna.

connectorized mounting styles.

Figure 41: Whip Style Antennas

The wavelength of the operational frequency determines

234

an antenna’s overall length. Since a full wavelength

is often quite long, a partial ½- or ¼-wave antenna

is normally employed. Its size and natural radiation

resistance make it well matched to Linx modules.

The proper length for a straight ¼-wave can be easily

determined using the formula in Figure 42. It is also

possible to reduce the overall height of the antenna by

L =

MHz

Figure 42:

L = length in feet of

quarter-wave length

F = operating frequency

in megahertz

Figure 45: SP Series

“Splatch” Antenna

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

Linx offers a wide variety of specialized antenna

styles (Figure 43). 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

Figure 43: Specialty Style

Antennas

antenna can detune in proximity to other objects, so

care must be exercised in layout and placement.

–

Questions regarding interpretations of the Part 2 and Part 15 rules or the

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:

Regulatory Considerations

Note: Linx RF modules are designed as component devices that require

external components to function. The purchaser understands that

additional 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.

Federal Communications Commission

Equipment Authorization Division

Customer Service Branch, MS 1300F2

7435 Oakland Mills Road

Columbia, MD, US 21046

Phone: + 1 301 725 585 | Fax: + 1 301 344 2050

Email: labinfo@fcc.gov

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 a completed

product.

ETSI Secretaria

650, Route des Lucioles

06921 Sophia-Antipolis Cedex

FRANCE

Phone: +33 (0)4 92 94 42 00

Fax: +33 (0)4 93 65 47 16

For information about regulatory approval, read AN-00142 on the Linx

website or call Linx. Linx designs products with worldwide regulatory

approval in mind.

International approvals are slightly more complex, although Linx modules

are designed to allow all international standards to be met. If the end

product is to be exported to other countries, contact Linx to determine the

speciﬁc suitability of the module to the application.

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 United States 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 FCC’s

website, 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. Final compliance testing is 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 the completed product has passed,

an ID number is issued that is to be clearly placed on each product

manufactured.

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.

–

Achieving a Successful RF Implementation

Adding an RF stage brings an exciting new

dimension to any product. It also means

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

DECIDE TO UTILIZE RF

RESEARCH RF OPTIONS

that additional effort and commitment will be

needed to bring the product successfully to

market. By utilizing pre-made RF modules

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 in Figure 46.

ORDER EVALUATION KIT(S)

TEST MODULE(S) WITH

BASIC HOOKUP

www.linxtechnologies.com or by contacting the Linx literature department.

CHOOSE LINX MODULE

Helpful Application Note Titles

Note Number

AN-00100

AN-00126

AN-00130

AN-00140

AN-00160

AN-00500

AN-00501

Note Title

INTERFACE TO CHOSEN

CIRCUIT AND DEBUG

RF 101: Information for the RF Challenged

Considerations for Operation Within the 902–928MHz Band

Modulation Techniques for Low-Cost RF Data Links

The FCC Road: Part 15 from Concept to Approval

Considerations for Sending Data Over a Wireless Link

Antennas: Design, Application, Performance

Understanding Antenna Speciﬁcations and Operation

CONSULT LINX REGARDING

ANTENNA OPTIONS AND DESIGN

LAY OUT BOARD

In reviewing this sample design path, you

may notice that Linx offers a variety of

services (such as antenna design and FCC

pre-qualiﬁcation) that are unusual for a

high-volume component manufacturer. These

services, along with an exceptional level

of technical support, are offered because

we recognize that RF is a complex science

requiring the highest caliber of products and

support. “Wireless Made Simple” is more than

just a motto: it’s our commitment. By choosing

Linx as your RF partner and taking advantage

of the resources we offer, you will not only

survive implementing RF, you may even ﬁnd the

process enjoyable.

SEND PRODUCTION-READY

PROTOTYPE TO LINX

FOR EMC PRESCREENING

OPTIMIZE USING RF SUMMARY

GENERATED BY LINX

Figure 47: Helpful Application Note Titles

SEND TO PART 15

TEST FACILITY

RECEIVE FCC ID #

COMMENCE SELLING PRODUCT

Figure 46: Typical Steps for

Implementing RF

–

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

OR FOR ANY OTHER BREACH OF CONTRACT BY LINX TECHNOLOGIES. The limitations on Linx Technologies’

liability are applicable to any and all claims or theories of recovery asserted by Customer, including, without

limitation, breach of contract, breach of warranty, strict liability, or negligence. Customer assumes all liability

(including, without limitation, liability for injury to person or property, economic loss, or business interruption) for

all claims, including claims from third parties, arising from the use of the Products. The Customer will indemnify,

defend, protect, and hold harmless Linx Technologies and its ofﬁcers, employees, subsidiaries, afﬁliates,

distributors, and representatives from and against all claims, damages, actions, suits, proceedings, demands,

assessments, adjustments, costs, and expenses incurred by Linx Technologies as a result of or arising from any

Products sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for

losses arising from the use or failure of the device in any application, other than the repair, replacement, or refund

limited to the original product purchase price. Devices described in this publication may contain proprietary,

patented, or copyrighted techniques, components, or materials. Under no circumstances shall any user be

conveyed any license or right to the use or ownership of such items.

The stylized Linx logo, Wireless Made Simple, WiSE, CipherLinx and the stylized CL logo are trademarks of Linx Technologies.

AN-00100 [ETC]

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