SX1240
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
SX1240 - Low Cost Integrated Transmitter IC
434 MHz and 868 MHz Band RF Transmitter
GENERAL DESCRIPTION
The SX1240 is an ultra-low-cost, fully integrated FSK or
OOK compatible transmitter suitable for operation in the
418, 434 and 868 MHz licence free ISM bands.
For applications where economy is paramount, the SX1240
may be used without the requirement for configuration via
an MCU. The transmitter is configured for default operation
at a frequency of 433.92 MHz or 868.3 MHz. However, in
conjunction with a microcontroller the communication link
parameters may be re-configured. Including, output power,
modulation format and operating channel.
The SX1240 offers integrated radio performance with cost
efficiency and is suited for worldwide operations in
particular Europe (ETSI EN 300-220-1), North America
(FCC part 15.231).
APPLICATIONS
Low-Cost Consumer Electronic Applications
Remote Keyless Entry (RKE)
Remote Control / Security Systems
Audio Accessories
Process and building / home control
Active RFID
KEY PRODUCT FEATURES
+10 dBm or 0 dBm Configurable output power
Bit rates up to 100 kbps
FSK and OOK modulation
2 Preconfigured Modes for Operation without MCU
433.92 MHz OOK & 868.3 MHz FSK
ORDERING INFORMATION
Part Number
SX1240ISTRT
Temperature Range
-40 °C to +85 °C
Qty. per Reel
2500
Package
SOIC8-EP
1.8 to 3.7 V supply range
Low BOM Fully Integrated Tx
8 Selectable Centre Frequencies
Programmable Frequency Tuning of low cost XTAL
Pb-Free, Halogen Free, RoHS/WEEE compliant product.
SX1240, Rev 1, Oct 2010
©2010 Semtech Corp.
Page 1
www.semtech.com
SX1240
ADVANCED COMMUNICATIONS & SENSING
Table of contents
Section
Page
DATASHEET
1.
General Description ................................................................................................................................................. 3
1.1.
1.2.
1.3.
Pin Diagram ..................................................................................................................................................... 3
Marking Diagram.............................................................................................................................................. 4
Pin Description................................................................................................................................................. 4
ESD Notice ...................................................................................................................................................... 5
Absolute Maximum Ratings ............................................................................................................................. 5
Operating Range.............................................................................................................................................. 5
Timing Characteristics ..................................................................................................................................... 7
2.
Electrical Characteristics ......................................................................................................................................... 5
2.1.
2.2.
2.3.
2.5.
2.4. Electrical Specifications 6
3.
Application Modes ................................................................................................................................................... 8
3.1. Application Mode: Power & Go 9
3.1.1.
3.1.2.
3.2.
3.2.1.
3.2.2.
4.
5.
‘Power & Go’ Mode: Configuration............................................................................................................ 9
Transmitter Operation in ‘Power & Go’ Mode ........................................................................................... 9
Advanced Mode: Configuration............................................................................................................... 10
Transmitter Operation in Advanced Mode .............................................................................................. 11
Application Mode: Advanced ......................................................................................................................... 10
Configuration Register ........................................................................................................................................... 13
Application Information .......................................................................................................................................... 14
5.1.
5.2.
Crystal Specification ...................................................................................................................................... 14
Reference Design Schematics....................................................................................................................... 14
5.3. Reference Design PCB Layout 15
5.4. Reference Design BOM 16
6.
Packaging Information ........................................................................................................................................... 17
6.1.
6.2.
6.3.
7.
Package Outline Drawing .............................................................................................................................. 17
Land Pattern .................................................................................................................................................. 17
Tape & Reel Specification.............................................................................................................................. 18
Revision History..................................................................................................................................................... 19
SX1240, Rev 1, Oct 2010
©2010 Semtech Corp.
Page 2
www.semtech.com
SX1240
Integrated Transmitter IC
ADVANCED COMMUNICATIONS & SENSING
This product datasheet contains a detailed description of the SX1240 performance and functionality.
DATASHEET
1. General Description
The SX1240 is a fully-integrated frequency-agile, single chip transmitter IC capable of FSK and OOK modulation of an
input data stream. The full application circuit is shown in Figure 9. The SX1240 is configured, by default, to operate without
a microcontroller with its pre-configured RF settings (see Section 3 for precise details of the default settings). Selection is
made between 434 MHz and 868 MHz band operation by setting the Control pin (6) either high or low at power-up. A full
description of this functionality is given in Section 3.1.
Where greater flexibility is required, many of the default communication parameters can be dynamically configured. This
includes the operating frequency, frequency deviation and modulation format. Upon the application of a serial clock to the
Control pin (6), the Data pin (2) can be used to load a single 13-bit control word. Accessing this functionality is subject to
the connection of the control pin at start-up. For full details of this, the configuration bits and the precise timing operations
of this functionality please consult Section 3.2.
The SX1240 is designed for use with a variety of low-cost antenna technologies. A reference design with PCB-trace
antenna is presented in Section 5.
Another key feature of the SX1240 is its low current consumption in transmit and sleep modes and its wide voltage
operating range from 1.8 V to 3.7 V. This makes the SX1240 suitable for low-cost battery chemistries or energy harvesting
applications.
The internal architecture of the SX1240 is shown in Figure 1. The SX1240 comprises a low-consumption PLL and power
amplifier. For frequency modulation the modulation is performed digitally within the PLL bandwidth. OOK Modulation is
performed via ramping of the PA reference DAC.
1.1. Pin Diagram
Figure 1. Pinouts, Top View
SX1240, Rev 1, Oct 2010
©2010 Semtech Corp.
Page 3
www.semtech.com
SX1240
Integrated Transmitter IC
ADVANCED COMMUNICATIONS & SENSING
1.2. Marking Diagram
DATASHEET
Figure 2. Marking Diagram
Notes yyww refers to the date code
xxxxx refers to the lot number
1.3. Pin Description
Table 1
Description of the SX1240 Pinouts
Name
GND
DATA
GND
XTAL
VDD
CTRL
GND
RFOUT
Type
I
I/O
I
I/O
I
I
I
O
Transmit Data
Ground
Reference Crystal
Power Supply 1.8V to 3.7V
Config Selection
Ground
Transmitter RF Output
Configuration Data Clock
Function in ‘Power & Go’ Mode
Ground
Transmit or Configuration Data
Function in ‘Advanced’ Mode
Number
1
2
3
4
5
6
7
8
SX1240, Rev 1, Oct 2010
©2010 Semtech Corp.
Page 4
www.semtech.com
SX1240
Integrated Transmitter IC
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
2. Electrical Characteristics
2.1. ESD Notice
The SX1240 is a high performance radio frequency device, and satisfies Class 2 of the JEDEC
standard JESD22-A114-B (human body model) on all pins.
It should thus be handled with all necessary ESD precautions to avoid any permanent damage.
2.2. Absolute Maximum Ratings
Stresses above the values listed below may cause permanent device failure. Exposure to absolute maximum ratings for
extended periods may affect device reliability.
Table 2
Absolute Maximum Ratings
Symbol
Description
Supply Voltage
Temperature
Junction Temperature
Storage Temperature
Min
-0.5
-55
-55
-55
Max
3.9
+115
+125
150
Unit
V
°C
°C
°C
VDDmr
Tmr
Tjunc
Tstor
2.3. Operating Range
Operating ranges define the limits for functional operation and the parametric characteristics of the device as described in
this section. Functionality outside these limits is not implied.
Table 3
Operating Range
Symbol
Description
Supply voltage
Operational temperature range
Load capacitance on digital ports
Min
1.8
-40
-
Max
3.7
85
25
Unit
V
°C
pF
VDDop
Top
Clop
SX1240, Rev 1, Oct 2010
©2010 Semtech Corp.
Page 5
www.semtech.com
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