SX1243 DATASHEET WIRELESS & SENSING SX1243 - Low Cost Low Current Integrated Transmitter 310 to 928MHz Frequency Agile GENERAL DESCRIPTION APPLICATIONS The SX1243 is an ultra-low-cost, fully integrated FSK or OOK transmitter suitable for operation between 310 and 450 MHz, 860 and 870 MHz, as well as 902 and 928 MHz. For applications where economy is paramount, the SX1243 may be used without the requirement for configuration via an MCU. However, in conjunction with a microcontroller the communication link parameters may be re-configured. Including, output power, modulation format and operating channel. The SX1243 offers integrated radio performance with cost efficiency and is suited for operation in North America FCC Part 15.231, FCC Part 15.247 FHSS and Digital Modulation Techniques, 15.249, and Europe EN 300 220. ORDERING INFORMATION Part Number Temperature Range Package MOQ / Multiple SX1243IULTRT -40 °C to +85 °C DFN-UT8 3000 pieces Pb-Free, Halogen Free, RoHS/WEEE compliant product. NRESET Garage Door Openers Low-Cost Consumer Electronic Applications Remote Keyless Entry (RKE) Remote Control / Security Systems KEY PRODUCT FEATURES +10 dBm or 0 dBm Configurable output power Bit rates up to 100 kbps OOK and FSK modulation. 1.8 to 3.7 V supply range. Low BOM Fully Integrated Tx Fractional-N PLL with 1.5 kHz typical step Frequency agility for FHSS modulation FCC CFR Part 15.247 Digital Modulation Techniques RFOUT 1 8 PA DATA 2 7 CP GND XTAL SX1243, Rev 3, May 2012 ©2012 Semtech Corporation TX_READY M/N 3 PFD 4 Sigma /Delta 6 CTRL 1.8 to 3.7 V 5 Page 1 VDD www.semtech.com SX1243 DATASHEET WIRELESS & SENSING Table of contents Section 1. 2. 3. 4. 5. 6. 7. 8. Page Circuit Description ....................................................................................................................................................................... 3 1.1. General Description ............................................................................................................................................................ 3 1.2. Block Diagram .................................................................................................................................................................... 3 1.3. Pin Description, DFN8 Encapsulation................................................................................................................................. 4 Electrical Characteristics ............................................................................................................................................................. 5 2.1. ESD Notice ......................................................................................................................................................................... 5 2.2. Absolute Maximum Ratings ................................................................................................................................................ 5 2.3. Operating Range ................................................................................................................................................................ 5 2.4. Electrical Specifications........................................................................................................................................................... 6 Digital Specification ..................................................................................................................................................................... 8 Application Modes of the SX1243 ............................................................................................................................................... 9 4.1. Transmitter Modes.............................................................................................................................................................. 9 4.2. Mode Selection Flowchart ................................................................................................................................................ 10 4.3. Application Mode: Power & Go ............................................................................................................................................. 11 4.4. Application Mode: Advanced ............................................................................................................................................ 11 4.4.1. Advanced Mode: Configuration................................................................................................................................. 11 4.4.2. Frequency Hopping Spread Spectrum...................................................................................................................... 11 4.5. Frequency Band Coverage ................................................................................................................................................... 12 4.6. Power Consumption ......................................................................................................................................................... 12 SX1243 Configuration ............................................................................................................................................................... 13 5.1. TWI Access....................................................................................................................................................................... 13 5.2. APPLICATION Configuration Parameters ........................................................................................................................ 15 5.3. FREQUENCY Configuration Parameters ......................................................................................................................... 15 5.4. Test Parameters ............................................................................................................................................................... 16 5.5. Status Parameters ............................................................................................................................................................ 16 5.6. Recovery Command .............................................................................................................................................................. 17 Application Information.............................................................................................................................................................. 18 6.1. Crystal Specification ......................................................................................................................................................... 18 6.2. Evaluation Module ............................................................................................................................................................ 18 6.3. NRESET Pin ..................................................................................................................................................................... 20 6.4. TX_READY Pin................................................................................................................................................................. 20 6.5. Low Power Optimization ................................................................................................................................................... 20 6.5.1. 2 Connections: CTRL, DATA .................................................................................................................................... 20 6.5.2. 3 Connections: CTRL, DATA, TX_READY ............................................................................................................... 20 SX1243 Packaging.................................................................................................................................................................... 21 7.1. Package Outline Drawing ................................................................................................................................................. 21 7.2. Thermal Impedance.......................................................................................................................................................... 21 7.3. Land Pattern ..................................................................................................................................................................... 22 7.4. Tape & Reel Specification ................................................................................................................................................ 22 Revision History ........................................................................................................................................................................ 23 SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 2 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING This product datasheet contains a detailed description of the SX1243 performance and functionality. 1. Circuit Description 1.1. General Description The SX1243 is a fully-integrated multi-band, single chip transmitter IC capable of FSK and OOK modulation of an input data stream. It contains a frequency synthesizer which is a fractional-N sigma-delta PLL. For frequency modulation (FSK), the modulation is made inside the PLL bandwidth. For amplitude modulation (OOK), the modulation is performed by turning on and off the output PA. The frequency reference used by the PLL is generated by a 22, 24 or 26 MHz crystal oscillator, depending on the frequency band of interest. The Power Amplifier (PA), connected to the RFOUT pin, can deliver 0 dBm or +10 dBm in a 50 Ω load. Each of these two output powers need a specific matching network when efficiency needs to be optimized. The circuit can be configured via a simplified TWI interface, constituted of pin CTRL and DATA. The pins of this interface are also used to transmit the modulating data to the chip. Another key feature of the SX1243 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 SX1243 suitable for low-cost battery chemistries or energy harvesting applications. 1.2. Block Diagram The figure below shows the simplified block diagram of the SX1243 die mounted in a DFN8 package. NRESET RFOUT 1 8 PA DATA 2 7 CP GND XTAL TX_READY M/N 3 PFD 6 4 Sigma /Delta 5 CTRL 1.8 to 3.7 V VDD Figure 1. SX1243 Simplified Block Diagram and BOM SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 3 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 1.3. Pin Description, DFN8 Encapsulation Table 1 Description of the SX1243 DFN8 Pinouts Number Name Type Function in ‘Power & Go’ Modes Function in ‘Advanced’ Mode 0 GND I Exposed Pad, Ground 1 NRESET I Reset (Optional, can be left floating) 2 DATA I/O 3 GND I Ground 4 XTAL I/O Reference Crystal 5 VBAT I Power Supply 1.8V to 3.7V 6 CTRL I 7 TX_READY O Transmitter Ready Flag (Optional, can be left floating) 8 RFOUT O Transmitter RF Output SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Transmit Data Config Selection Page 4 Transmit or Configuration Data Configuration Data Clock www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 2. Electrical Characteristics 2.1. ESD Notice The SX1243 is an electrostatic discharge sensitive device. It satisfies Class 2 of the JEDEC standard JESD22-A114-B (Human Body Model) on all pins. 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 SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 5 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 2.4. Electrical Specifications The table below gives the electrical specifications of the transmitter under the following conditions: Supply voltage VBAT = 3.3 V, temperature = 25 °C, fXOSC = 26 MHz, fRF = 915 MHz, 2-FSK modulation with Fdev=+/-10 kHz, bit rate = 10 kbit/s and output power = +10 dBm terminated in a matched 50 Ohm impedance, unless otherwise specified. Table 4 Symbol Transmitter Specifications Description Conditions Min Typ - 125 Max Unit Current Consumption IDDSL Supply current in Sleep mode nA IDDT_315 Supply current in Transmit mode at 315 MHz* RFOP=+10dBm 50% OOK RFOP=+10dBm FSK RFOP=0dBm FSK - 11 15 9 - mA mA mA IDDT_915 Supply current in Transmit mode at 915 MHz* RFOP=+10dBm FSK RFOP=0dBm FSK - 17.5 10.5 - mA mA RF and Baseband Specifications FBAND Accessible Frequency Bands Band 0, with FXOSC=22 MHz 310 - 450 MHz See details in Table 7. Band 0, with FXOSC=24 MHz 312 - 450 MHz Band 0, with FXOSC=26 MHz 338 - 450 MHz Band 1, with FXOSC=26 MHz 860 902 - 870 928 MHz MHz 10 - 200 kHz FDA Frequency deviation, FSK BRF Bit rate, FSK Permissible Range 0.5 - 100 kbps BRO Bit rate, OOK Permissible Range 0.5 - 10 kbps OOK_B OOK Modulation Depth - 45 - dB RFOP RF output power in 50 Ohms in either frequency band High Power Setting Low Power Setting* 7 -3 10 0 - dBm dBm RFOPFL RF output power flatness From 315 to 390 MHz, 50 Ohms load - 2 - dB DRFOPV Variation in RF output power with supply voltage 2.5 V to 3.3 V 1.8 V to 3.7 V - - 3 7 dB dB PHN Transmitter phase noise At offset: 100 kHz 350 kHz 550 kHz 1.15 MHz - -84 -94 -96 -105 - dBc/Hz dBc/Hz dBc/Hz dBc/Hz STEP_22 RF frequency step FXOSC = 22 MHz, Band 0 - 1.34277 - kHz STEP_24 RF frequency step FXOSC = 24 MHz, Band 0 - 1.46484 - kHz STEP_26 RF frequency step FXOSC = 26 MHz, Band 0 FXOSC = 26 MHz, Band 1 - 1.58691 3.17383 - kHz kHz SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 6 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING Symbol Description FXOSC Crystal Oscillator Frequency DFXOSC Frequency Variation of the XOSC Conditions Min Typ Max Unit - 22 24 26 - MHz MHz MHz No crystal contribution - - +/-25 ppm XTAL dependant, with spec’d XTAL - 650 2000 us Timing Specifications TS_TR Time from Sleep to Tx mode TS_HOP0 Channel hop time in Band 0 315 to 390 MHz - 250 500 us TS_HOP1 Channel hop time in Band 1 Maximum hop of 26 MHz*** - 200 400 us TOFFT Timer from Tx data activity to Sleep Programmable - 2 20 - ms ms RAMP PA Ramp up and down time - 20 - us T_START Time before CTRL pin mode selection. - 200 us + TS_OSC - ms Time from power on to sampling of CTRL ** * With different matching networks ** The oscillator startup time, TS_OSC, depends on the electrical characteristics of the crystal *** From the last CTRL falling edge of the Frequency change instruction to transmitter ready (PA ramp up finished) SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 7 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 3. Digital Specification The following table gives the operating specifications for the digital inputs and outputs of the SX1243. Table 5 Digital Signals Specification Symbol Description VIH Min Typ Max Unit Digital input level high 0.8 - - VBAT VIL Digital input level low - - 0.2 VBAT VOH Digital output level high Imax = 1 mA 0.9 - - VBAT VOL Digital output level low Imax = -1 mA - - 0.1 VBAT fCTRL CTRL Clock Frequency - - 10 MHz tch CTRL Clock High time 45 - - ns tcl CTRL Clock Low time 45 - - ns trise CTRL Clock rise time - - 5 ns tfall CTRL Clock Fall time - - 5 ns tsetup DATA Setup time From Data transition to CTRL rising edge 45 - - ns thold DATA hold time From CTRL rising edge to DATA transition 45 - - ns t0, t2 Time at “1” on DATA during Recovery command See Figure 9 and Figure 10 - - 5 us t1 Time at “0” on DATA during Recovery command See Figure 10 5 - - us SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Conditions Page 8 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 4. Application Modes of the SX1243 Pins CTRL and DATA are used for both configuring the circuit and sending the data to be transmitted over the air. Two different modes are associated to these pins, “Power&Go” and “Advanced” modes. 4.1. Transmitter Modes Automatic Mode operation is described in Figure 2. Here we see that a rising edge on the DATA pin activates the transmitter start-up process. DATA must be held high for the start-up time (TS_TR) of the SX1243. During this time the SX1243 undergoes an optimized, self-calibrating trajectory from Sleep mode to Transmit mode. Once this time has elapsed, the SX1243 is ready to transmit. Any logical signal subsequently applied to the DATA pin is then transmitted. Figure 2. ‘Power & Go’ Mode: Transmitter Timing Operation The transition back to Sleep mode is managed automatically. The SX1243 waits for TOFFT (2 or 20 ms) of inactivity on DATA before returning to Sleep mode. In Forced Transmit Mode the circuit can be forced to wake up and go to TX mode by sending an APPLICATION instruction through the TWI interface, and setting the Mode bit DA(15) to ‘1’. Once in Transmit the circuit will transmit over the air the data stream presented on the DATA pin. The circuit will stay in transmit mode until a new APPLICATION instruction is sent with DA(15) to ‘0’. Figure 3. Forced Transmit Mode Description SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 9 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 4.2. Mode Selection Flowchart Circuit Start-up Wait T_Start Logic ‘0’ Check CTRL Pin Power & Go 1 868.3 MHz FSK, Fdev=+/-19.2kHz +10dBm Logic ‘1’ Power & Go 2 433.92 MHz OOK +10dBm CTRL Clock signal Advanced Mode Full register flexibility Automatic or forced Transmit Figure 4. SX1243 Mode Selection Note Advanced mode is entered only if DATA is held low during CTRL’s rising edge. When powering up the circuit (microcontroller and SX1243), the logic level of the CTRL pin is sampled after T_START, as described on Figure 5. During T_START, the microcontroller IO driving the CTRL pin must be configured as an output, driving the CTRL pin to the desired state. Figure 5. Power-up Timing SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 10 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 4.3. Application Mode: Power & Go The default ‘Power & Go’ application mode sees the SX1243 configured as detailed in Table 6. By changing the logical state of the CTRL pin at Power-up or Reset, two distinct configuration modes can be selected. The Power & Go application modes hence permit microcontroller-less operation. Table 6 Configuration in Power & Go Mode CTRL Pin Configuration Mode ‘Low’ FSK 868.3 MHz, +10 dBm, Fdev=+/-19.2 kHz Power&Go 1 ‘High’ OOK 433.92 MHz, +10 dBm Power&Go 2 4.4. Application Mode: Advanced 4.4.1. Advanced Mode: Configuration As described on Figure 4, Advanced mode is entered when accessing the Two Wire Interface (TWI) bus of the SX1243. Upon communication to the register at up to 10 MHz of clocking speed, complete flexibility on the use of the chip is obtained. Once all register settings are selected (see registers detailed description in section [5]), the SX1243 can be used either in Automatic mode by simply toggling the DATA pin, or in Forced Transmit mode to optimize timings for instance. 4.4.2. Frequency Hopping Spread Spectrum Frequency hopping is supported in Advanced mode. After sending the data stream in the first channel, the user can send a Frequency change instruction containing the new channel frequency. The circuit will automatically ramp down the PA, lock the PLL to the new frequency, and turn the Power Amplifier back on. The user can then send his packet data on the new channel. Timings are detailed hereafter: t < TOFFT (2 or 20 ms) TWI instruction DATA Frequency change CTRL Frequency change t < TOFFT (2 or 20 ms) RFOUT 5th falling edge on CTRL 24th falling edge on CTRL TS_HOPi Tx Channel A Tx Channel B Figure 6. Frequency Hopping Description Notes - During any TWI access, the input of the modulator is inhibited - The time between two Frequency change instructions shall be greater than TS_HOPi - FHSS modulation, as described under FCC part 15.247, is supported by the SX1243; also note that the large Frequency Deviation settings available on the SX1243 make it suitable for “Digitally Modulated Systems”, as described under FCC Part 15.247 (a)(2) SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 11 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 4.5. Frequency Band Coverage The SX1243 offers several combinations or frequency references and frequency outputs, allowing for maximum flexibility and design of multi-band products: Table 7 Frequency Selection Table Reference Frequency FXOSC Band Setting DA(13) Upper / Lower Frequency Bounds Fstep 310 to 450 MHz 22x10 Fstep = ----------------= 1.34277kHz 14 2 312 to 450 MHz 24x10 Fstep = ----------------= 1.46484kHz 14 2 338 to 450 MHz 26x10 Fstep = ----------------= 1.58691kHz 14 2 860 to 870 MHz and 902 to 928 MHz 26x10 = 3.17383kHz Fstep = ----------------13 2 Frf & Fdev 6 22 MHz 6 24 MHz 0 6 Frf = DF ( 18 ;0 ) × Fstep Fdev = DA ( 12 ;5 ) × Fstep 26 MHz 1 6 4.6. Power Consumption The following typical power consumption figures are observed on the SX1243 kits. Note that the transmitter efficiency depends on the impedance matching quality, and can be PCB design dependant. The PA matching may be different in each frequency band. Table 8 Power Consumption in Tx mode Typical Current Drain Frequency Band Conditions 310 to 450 MHz Pout=+10dBm, OOK modulation with 50% duty cycle Pout=+10dBm, FSK modulation Pout=0dBm, FSK modulation 860 to 870 MHz Pout=+10dBm, FSK modulation Pout=0dBm, FSK modulation 16.5 mA 10 mA 902 to 928 MHz Pout=+10dBm, FSK modulation Pout=0dBm, FSK modulation 17.5 mA 10.5 mA SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 12 11 mA 15 mA 9 mA www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 5. SX1243 Configuration The SX1243 has several configuration parameters which can be selected through the serial interface 5.1. TWI Access As long as CTRL is kept stable, the DATA pin is considered by the circuit as the input for the data to be transmitted over the air (Power&Go modes). Programming of the configuration register is triggered by a rising edge on the CTRL line. Upon detection of this rising edge, the data applied to the DATA pin is accepted as register configuration information, the data bits are clocked on subsequent rising edges of the clocking signal applied to the CTRL pin. The timing for SX1243 configuration register ‘write’ is shown in Figure 7. Note that, once triggered, all 24 clock cycle must be issued to the SX1243. CTRL DATA 1st 2nd 23rd 24th DATA pin is an input Figure 7. TWI Configuration Register ‘Write’. The registers may, similarly, be read using the timing of Figure 8. CTRL DATA 1st 2nd 8th 24th DATA pin is an output DATA pin is an input Figure 8. TWI Configuration Register ‘Read’. The first rising edge on CTRL which initiates the ADVANCED mode must occur at least 1 ms after the circuit has been powered up or reset. SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 13 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING Table 9 TWI Instruction Table Byte 0 Byte 1 Byte 2 Instruction 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 0 0 0 0 (0000) DA(15:0) 0 0 0 1 1 0 0 1 0 Write Application bits DF(18:0) (0)(0010)(0010) Write Frequency bits DT(10:0) Write Test bits (pad protected) 0 0 1 1 (0011) DA(15:0) Read Application bits 0 1 0 0 (0100) DF(15:0) Read the 16 least significant Frequency bits 0 1 0 1 (0101) 0 1 1 0 (0110) 0 1 1 1 (0111) 1 DS(12:5) DS(4:0) DF(18: Read Chip version, Status and 3 most significant 16) Frequency bits DS(28:13) (1111)(1) Read Bist signature DT(10:0) Read Test bits x Discarded, not an instruction All 1 Recovery instruction Notes - The first “0” transmitted to the SX1243 is required to initialize communication - The following 3 bits (highlighted in blue) determine the type of instruction - The forthcoming bits (highlighted in green) define a protection pattern; any error in these bits voids the instruction SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 14 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 5.2. APPLICATION Configuration Parameters Name Mode Number DA(15) Description Power &Go 1 Power &Go 2 0 Mode: 0 Æ Automatic mode 1 Æ Forced transmit mode Modul DA(14) Modulation scheme: 0 1 1 0 0x06 Fdev= +/-19.2kHz Unused 1 1 0 1 100 100 0 Æ FSK 1 Æ OOK Band DA(13) Fdev DA(12:5) Band 0, 310 to 450 MHz Band 1, 860 to 870 MHz and 902 to 928 MHz RF Frequency deviation in FSK mode only See Table 7 for details Pout DA(4) Output power range: 0 Æ 0 dBm 1 Æ 10 dBm TOFFT DA(3) Period of inactivity on DATA before SX1243 enters Sleep mode in Automatic mode: 0 Æ 2 ms 1 Æ 20 ms RES DA(2:0) Reserved Table 10 APPLICATION Configuration Parameters Note All changes to the APPLICATION parameters must be performed when the device is in Sleep mode, with the exception of DA(15). Mode can be sequentially written to “1”, and then “0” while the device is in Transmit mode, to speed up the turn off process and circumvent the TOFFT delay. 5.3. FREQUENCY Configuration Parameters Name Frf Number DF(18:0) Description Power &Go 1 Power &Go 2 RF operating frequency 0x42CAD 0x42C1C See Table 7 for details Frf=868.3 MHz With 26 MHz reference Frf=433.92 MHz With 26 MHz reference Table 11 FREQUENCY Configuration Parameters If done in Sleep mode, the Frequency change instruction will be applied next time the SX1243 is turned on. If Frequency change occurs during transmission, the automated Frequency Hopping sequence described in section [4.4.2] will take place. SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 15 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 5.4. Test Parameters Ten Test bits DT(9:0) exist in the SX1243. They are only use for the industrial test of the device, and therefore they are pad protected. It means that their value cannot be modified without applying a specific logical level to some of the SX1243 pads during a write access. 5.5. Status Parameters DS(12:5) are read-only bits, organized as follows: Name Number Default Advanced Mode Description Power &Go 1 RES DS(28:13) Reserved Chip Version DS(12:5) Chip identification number RES DS(4:2) Reserved - TX_READY DS(1) TX_READY, see section [6.5.1] 0 Æ Transmitter not Ready 1 Æ Transmitter is Ready - RES DS(0) Reserved - Power &Go 2 “0001 0001” --> V1A Table 12 Status Read-Only Parameters SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 16 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 5.6. Recovery Command In the event of spurious activity (less than 24 clock cycles received) on the CTRL pin, control over the TWI interface can be recovered in two possible ways: t2 Recovery Command DATA CTRL 1st rising edge on CTRL 24th rising edge on CTRL Figure 9. Quick Recovery Command t1 t0 DATA CTRL 1st rising edge 24th rising edge Figure 10. Pulsed Recovery Command Notes - If t2 < 5 us, the SX1243 will not turn into Tx mode during the recovery command (if not previously in Tx mode) - If t1 < 5 us, with t0 > 5 us, the SX1243 will not turn into Tx mode in the second scenario of recovery command - During the Pulsed recovery command, t0 timing does not have any upper limit - If t1 or t2 exceeds 5us, the recovery command will still be successful, but the transmitter will momentarily turn on SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 17 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 6. Application Information 6.1. Crystal Specification The SX1243 is designed to operate with a low-cost 22, 24 or 26 MHz crystal Table 13 SX1243 Quartz Crystal Reference Oscillator Specification Symbol Description Min Typ Max Unit FXOSC Crystal Frequency - 22 24 26 - MHz LM Crystal Motional Inductance - 14.970 13.700 12.655 - mH CM Crystal Motional Capacitance - 3.495 3.209 2.962 - fF RS Crystal Serial Resistance - 20 100 Ohms C0 Crystal Shunt Capacitance - 1.0 7.0 pF CL Load Capacitance - 15 - pF 6.2. Evaluation Module Figure 11. Evaluation Board Schematic The evaluation module, presented in Figure 11, allows for the seamless evaluation of the SX1243 circuit. Several BOM options are offered to evaluate the performance in all frequency bands. SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 18 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING The SX1243 reference design uses a tiny footprint of 16 x 6 mm, allowing for compact implementations on 2-layer PC Boards. Figure 12. Evaluation Board Layout Top, Bottom Views The following BOMs guarantee that the SX1243 product will be able to meet all regional regulatory requirements, with significant margin (more than 10dB) on the rejection of harmonics and spurs. Label L1 L2 L3 L4 C1 C2 C3 C4 C5 C6 C7 C8 Decoupling C9 R5 Delayed C10 POR L5 Antenna C11 Match C12 Inductor count Capacitor count Resistor count PA Matching and Harmonic Filtering Usage 350 MHz 120nH 39nH 15nH 0 Ohm 2.2pF 100pF 8.2pF 3.3pF 8.2pF 100pF 100nF - 433 MHz 120nH 33nH 15nH 0 Ohm 0.5pF 100pF 8.2pF 2.2pF 8.2pF 100pF 100nF - 915 MHz 868 MHz @+10dBm 22nH 22nH 12nH 12nH 4.7nH 6.8nH 8.2nH 0 Ohm 0.5pF 33pF 18pF 1.8pF 5.6pF 1.5pF 1.8pF 2.2pF 18pF 100pF 100pF 100nF 100nF - 915 MHz @0dBm 22nH 12nH 6.8nH 6.8nH 0.5pF 18pF 5.6pF 2.2pF 18pF 100pF 100nF - Type Tolerance LQG15xxx NPO Standard tolerance NPO X7R - Antenna dependant 3 7 1 3 7 1 4 7 0 3 6 1 4 7 0 Figure 13. Evaluation Board BOMs SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 19 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING Notes - The matching centered at 350 MHz offers a flat performance from 315 to 390 MHz, but could be modified to slightly improve efficiency at any frequency inbetween - The 915 MHz @10dBm BOM is dedicated to systems running under CFR Part 15.247, either Frequency Hopping Spread Spectrum or Digital Modulation Techniques operation - The 915 MHz @0dBm BOM is dedicated to systems running under CFR Part 15.249 6.3. NRESET Pin When required, the pin NRESET can be controlled externally, to allow for: either a delayed Power On Reset (POR) cycle of the SX1243, allowing for the companion micro to reset and assign its port directions. This is achieved by connecting a R/C time constant to the NRESET pin. or an On-the-go Reset of the SX1243 at any moment in time, if required by the application. This is achieved by pulling the NRESET pin low for more than 100 microseconds, then releasing it to high impedance (normal termination). 6.4. TX_READY Pin For timing critical applications, TX_READY pin can be useful to know precisely when the transmitter is ready for operation and therefore save energy. As an option TX_READY can be connected to inform the companion device that the PA ramp up phase has been terminated, hence the SX1243 is ready for data transmission. 6.5. Low Power Optimization The SX1243 is designed to reduce the cost of the RF transmitter functionnality. To this end, a single DATA signal can be enough to operate the transmitter, in any of the two Power & Go modes. In this situation, TS_START and TOFFT timings, tabulated in Section 2.4, must be respected, leading to significant periods of time during which the transmitter is On and no valuable information is transmitted. For more demanding applications where energy usage is critical, the SX1243 offers hardware and software support to accurately control the transmitter On time, and therefore save energy: 6.5.1. 2 Connections: CTRL, DATA If the two signals of the TWI interface can be controlled by the host microcontroller, Tx On time and energy usage can be optimized as follows: At the device turn on, instead of waiting for TS_TR (2ms max, but XTAL dependant), the status flag TX_READY can be polled on the TWI interface. As soon as the TX_READY flag is set, the microcontroller can start toggling DATA to transmit the useful packet. This method is only valid in Forced Tx mode. At the device turn off, the user can immediately turn off the transmitter after the transmission of packet, assuming that the Forced Transmit mode was used. 6.5.2. 3 Connections: CTRL, DATA, TX_READY In applications where the number of connections between the microcontroller and the RF chip is less critical, TX_READY pin can be connected to either a GPIO port, or an external interrupt port of the micro. The two optimizations described in the former subsection will also be possible. SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 20 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 7. SX1243 Packaging 7.1. Package Outline Drawing Figure 14. Package Outline Drawing 7.2. Thermal Impedance The thermal impedance of this package, calculated from a package in still air, on a 4-layer FR4 PCB, as per the Jedec standard, is Theta ja = 67 °C/W typ. SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 21 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 7.3. Land Pattern Figure 15. Land Pattern 7.4. Tape & Reel Specification Figure 16. Tape & Reel Specification, DFN Package SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 22 www.semtech.com SX1243 Integrated Transmitter IC DATASHEET WIRELESS & SENSING 8. Revision History Table 14 Revision History Revision Date 1 January 2012 First FINAL release Add Tape and Reel specification Add Minimum Order Quantity Add Thermal Impedance of the package 2 February 2012 Add digital pins specifications Typographical corrections Modify section [6.5.1] 3 May 2012 Adjust Electrical specifications SX1243, Rev 3, May 2012 ©2012 Semtech Corporation Page 23 Comment www.semtech.com SX1243 DATASHEET WIRELESS & SENSING © Semtech 2012 All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. 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