SX1242 DATASHEET ADVANCED COMMUNICATIONS & SENSING SX1242 - Low Cost Integrated Transmitter IC 344.940 MHz RF Transmitter GENERAL DESCRIPTION APPLICATIONS The SX1242 is an ultra-low-cost, fully integrated standalone OOK transmitter suitable for operation at 344.940 MHz The SX1242 is designed for use without the requirement for configuration via an MCU. The SX1242 offers integrated radio performance with cost efficiency and is suited for operation in North America (FCC part 15.231). Part Number Temperature Range Qty. per Reel Package SX1242ISETRT -40 °C to +85 °C 2500 SOIC8-EP Pb-Free, Halogen Free, RoHS/WEEE compliant product. DATA GND XTAL SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Low-Cost Consumer Electronic Applications Remote Keyless Entry (RKE) Remote Control / Security Systems Audio Accessories Process and building / home control KEY PRODUCT FEATURES ORDERING INFORMATION GND +12 dBm Output Power 344.940 MHz Operation OOK Bit Rates up to 10 kbps Pre-Configured Modes for Operation without MCU 1.8 to 3.7 V Supply Range Low BOM Fully Integrated TX 1 8 RFOUT v v v VDD 2 3 M/N CP PFD 7 6 TX ENABLE VDD 4 ΣΔ Page 1 5 v www.semtech.com SX1242 ADVANCED COMMUNICATIONS & SENSING DATASHEET Table of contents Section 1. 2. General Description ................................................................................................................................................. 3 1.1. Pin Diagram ..................................................................................................................................................... 3 1.2. Marking Diagram.............................................................................................................................................. 4 1.3. Pin Description................................................................................................................................................. 4 Electrical Characteristics ......................................................................................................................................... 5 2.1. 3. 4. 5. 6. Page ESD Notice ...................................................................................................................................................... 5 2.2. Absolute Maximum Ratings ............................................................................................................................. 5 2.3. Operating Range.............................................................................................................................................. 5 2.4. Electrical Specifications ................................................................................................................................... 6 Circuit Description.................................................................................................................................................... 7 Application Information ............................................................................................................................................ 9 4.1. Crystal Specification ........................................................................................................................................ 9 4.2. Reference Design Schematic .......................................................................................................................... 9 4.3. Reference Design PCB Layout ......................................................................................................................10 4.4. Reference Design BOM .................................................................................................................................10 Packaging Information ........................................................................................................................................... 11 5.1. Package Outline Drawing .............................................................................................................................. 11 5.2. Land Pattern .................................................................................................................................................. 11 5.3. Thermal Impedance ....................................................................................................................................... 12 5.4. Tape & Reel Specification.............................................................................................................................. 12 Revision History..................................................................................................................................................... 13 SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 2 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING This product datasheet contains a detailed description of the SX1242 performance and functionality. 1. General Description The SX1242 is a fully-integrated multi-band, single chip transmitter IC capable of OOK modulation of an input data stream. The SX1242 is configured, by default, to operate without a microcontroller at a pre-configured RF setting of 344.940 MHz. Another key feature of the SX1242 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 SX1242 suitable for low-cost battery chemistries or energy harvesting applications. The internal architecture of the SX1242 is shown in Figure 1. The SX1242 comprises a low-consumption PLL and power amplifier. OOK Modulation is performed via ramping of the PA reference DAC. The SX1242 is designed for use with a variety of low-cost antenna technologies including PCB-etched loop or electricallyshort stub. Further application information may be found in Section 4. 1.1. Pin Diagram GND 1 8 RFOUT DATA 2 7 VDD 0 GND 3 6 TX ENABLE XTAL 4 5 VDD Figure 1. Pinouts, Top View SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 3 www.semtech.com SX1242 Integrated Transmitter IC ADVANCED COMMUNICATIONS & SENSING DATASHEET 1.2. Marking Diagram SX1242 yyww xxxxx Figure 2. Marking Diagram Notes: yyww refers to the date code xxxxx refers to lot numbers 1.3. Pin Description Table 1 SX1242 Pinout Description Number Name Type 0 GND I Exposed Pad, Ground 1 GND I Ground 2 DATA I Transmit Data 3 GND I Ground 4 XTAL I/O 5 VDD I Power Supply, 1.8 V to 3.7 V 6 TX ENABLE I Control PIn for Transmitter 7 VDD I Power Supply, 1.8 V to 3.7 V 8 RFOUT O Transmitter RF Output SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Function Reference Crystal Page 4 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 2. Electrical Characteristics 2.1. ESD Notice The SX1242 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 Min Max Unit VDDmr Supply Voltage -0.5 3.9 V Tmr Temperature -55 +115 °C Tjunc Junction Temperature -55 +125 °C Tstor Storage Temperature -55 150 °C 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 Min Max Unit VDDop Supply voltage 1.8 3.7 V Top Operational temperature range -40 85 °C Clop Load capacitance on digital ports - 25 pF SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 5 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 2.4. Electrical Specifications The table below gives the electrical specifications of the transmitter under the following conditions: Supply voltage = 3.3 V, temperature = 25 °C, fXOSC = 26 MHz, fRF = 344.94 MHz, bit rate = 5 kbit/s and output power = +12 dBm terminated in a matched 50 ohm impedance, unless otherwise specified. Table 4 Symbol Transmitter Specifications Description Conditions Min Typ Max Unit - 0.5 1 µA - 22 - mA 0.5 - 10 kbps - 50 - dB 9 12 - dBm - - 3 7 dB dB - - -76 - 344.94 - MHz 26 26 26 MHz - - +/-25 ppm Current Consumption IDDSL Supply current in sleep mode IDDT Supply current in transmit mode with appropriate external matching. Logic “1” or “Mark” frequency transmitted* RF and Baseband Specifications BRO Bit rate, OOK OOK_B OOK modulation depth RFOP RF output power into 50 ohms DRFOPV Variation in RF output power with supply voltage PHN Transmitter phase noise FCN Carrier frequency FXOSC Crystal Oscillator Frequency DFXOSC Frequency Variation of the Oscillator Circuit Permissible range Optimized matching network 2.5 V to 3.3 V 1.8 V to 3.7 V 100 kHz Offset from carrier No crystal contribution dBc/Hz Timing Specifications TS_TR Time from Sleep to Tx mode - - 2 ms RAMP PA Ramp up and down time** - 20 - us * Logic “1” transmission indicated by transmission of carrier frequency at power level RFOP. ** Ramp-up time of the internal regulator turning the PA on. The typical 10% - 90% power ramp-up time is 10us SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 6 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 3. Circuit Description The SX1242 compromises a low-consumption fractional-N Sigma-Delta type PLL and power amplifier. A simplified block diagram of the internal architecture and application schematic is illustrated below in Figure 3 GND DATA GND XTAL 1 8 RFOUT v v v VDD 2 M/N CP 3 PFD 7 6 TX ENABLE VDD 4 ΣΔ 5 v Figure 3. SX1242 Simplified Block Diagram and Application Schematic 3.1. PLL The VCO operates at twice the RF channel frequency and is derived from a 26 MHz crystal oscillator reference 3.2. Transmitter The Power Amplifier (PA) is connected to the RFOUT pin and delivers 12 dBm in a 50 ohm load. The bit stream to be transmitted over the air is sent to the chip via the pin DATA. During modulation, the rising and falling transitions are smoothed with a ramp-up/ramp-down time of typically 20 μs via the PA reference DAC. 3.3. SX1242 Operating Modes The SX1242 operating modes are defined by the status of the pin TX ENABLE and are documented in Table 5. SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 7 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING Table 5 SX1242 Operating Modes TX Enable Status Mode Enabled Blocks 0 (GND) Sleep All blocks are off 1 (VDD) Transmit The blocks are switched on according to a predefined sequence and the data is transmitted once the sequence is completed The behavior of the SX1242 is illustrated in the timing diagram below: TS_TR DATA RFOUT TX ENABLE TRANSMIT SLEEP Figure 4. SX1242 Timing Diagram(Not to scale) SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 8 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 4. Application Information 4.1. Crystal Specification The SX1242 is designed to operate with a low-cost 26 MHz crystal. The recommended crystal specification is tabulated below in Table 6. Table 6 SX1242 Quartz Crystal Reference Oscillator Specification Symbol Description Conditions Min Typ Max FXOSC Crystal Frequency LM Unit 26 26 26 MHz Crystal Motional Inductance - 12.655 - mH CM Crystal Motional Capacitance - 2.962 - fF RS Crystal Serial Resistance - 20 100 Ohms C0 Crystal Shunt Capacitance - 1.0 7.0 pF CL Load Capacitance - 15 - pF 4.2. Reference Design Schematic VDD C11 GND C5 1 2 DATA 3 TX_EN L2 U1 SX1242 8 GND RFOUT DATA GND 4 XTAL C2 C6 C12 C4 VDD 7 TX EN L3 C3 C8 L1 6 VDD 5 C7 Q1 C10 Figure 5. Application Module Schematic SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 9 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 4.3. Reference Design PCB Layout The SX1242 reference design PCB layout is illustrated below: Figure 6. Reference Design PCB Layout 4.4. Reference Design BOM The following table summarizes the reference design BOM: Table 7 Reference Design BOM Re fDe s U1 Q1 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 L1 L2 L3 MPN SX1242ISETRT LQG15- or equivalent LQG15- or equivalent LQG15- or equivalent SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Pa ckage SO8 HC49 0402 0402 0402 0402 0402 0402 0402 0402 0402 0402 0402 0402 0402 Va lue SX1242 26 MHz 100pF 12pF 100nF 100pF 4.7pF 12pF 2.2pF 100nF 1uF Zero ohm 120nH 39nH 22n Page 10 Qty 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 De scription RF transmitter IC Crystal 26 MHz CL=15 pF Capacitor NPO (+/-5% ) Capacitor NPO (+/-5% ) Capacitor X7R (+/-5% ) Capacitor NPO (+/-5% ) Capacitor NPO (+/-0.25pF) Capacitor NPO (+/-5% ) Capacitor NPO (+/-0.25pF) Capacitor X7R (+/-5% ) Capacitor X5R (+/-5% ) Resistor Zero Ohm Multilayer chip inductor (+/-5% ) Multilayer chip inductor (+/-5% ) Multilayer chip inductor (+/-5% ) www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 5. Packaging Information The SX1242 is delivered in an SOIC package with 8 leads and an exposed pad. See details below. 5.1. Package Outline Drawing A D e N DIM 2X E/2 A A1 A2 b c D E1 E e F H h L L1 N 01 aaa bbb ccc E1 E 1 2 ccc C 2X N/2 TIPS e/2 B D aaa C A2 A SEATING PLANE C A1 bxN bbb DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX .053 .069 .000 .005 .049 .065 .012 .020 .007 .010 .189 .193 .197 .150 .154 .157 .236 BSC .050 BSC .086 .130 .085 .099 .010 .020 .016 .028 .041 (.041) 8 0° 8° .004 .010 .008 1.75 1.35 0.00 0.13 1.25 1.65 0.31 0.51 0.17 0.25 4.80 4.90 5.00 3.80 3.90 4.00 6.00 BSC 1.27 BSC 2.19 3.30 2.15 2.51 0.25 0.50 0.40 0.72 1.04 (1.05) 8 0° 8° 0.10 0.25 0.20 C A-B D h F EXPOSED PAD h H H c GAGE PLANE 0.25 SEE DETAIL L (L1) DETAIL A 01 A SIDE VIEW NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. Figure 7. Package Outline Drawing 5.2. Land Pattern E SOLDER MASK D DIM (C) F G Z Y THERMAL VIA Ø 0.36mm P X DIMENSIONS INCHES MILLIMETERS C D E F G P X Y Z (.205) .134 .201 .101 .118 .050 .024 .087 .291 (5.20) 3.40 5.10 2.56 3.00 1.27 0.60 2.20 7.40 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 3. REFERENCE IPC-SM-782A, RLP NO. 300A. 4. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. Figure 8. Land Pattern SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 11 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 5.3. Thermal Impedance The thermal impedance of this package is: Theta ja = 36° C/W typ., calculated from a package in still air, on a 4-layer FR4 PCB, as per the Jedec standard. 5.4. Tape & Reel Specification Carrier Tape Tape Width (W) 12 +/-0.30 Pocket Pitch (P) 8 +/-0.10 Reel Ao / Bo Ko Reel Size Reel Width Min. Trailer Length Min. Leader Length QTY per Unit 6.5 / 5.4 +/-0.30 2.00 +/-0.15 330.2 12.4 400 400 2500 mm Figure 9. Tape & Reel Specification Note Single Sprocket Holes SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 12 www.semtech.com SX1242 Integrated Transmitter IC DATASHEET ADVANCED COMMUNICATIONS & SENSING 6. Revision History Table 8 Revision History Revision Date 1 November 2010 First FINAL datasheet version 2 March 2011 Modified Application Schematic (Figure 5) SX1242, Rev 2, March 2011 ©2011 Semtech Corp. Page 13 Comment www.semtech.com SX1242 DATASHEET ADVANCED COMMUNICATIONS & SENSING © Semtech 2010 All rights reserved. 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