SX1276IMLTRT

Part: Semtech SX1276/77/78/79

Type: Low Power Long Range Transceiver

Description: The Semtech SX1276/77/78/79 are low power long range transceivers featuring LoRa™ modulation, operating from 137 MHz to 1020 MHz with a maximum link budget of 168 dB, +20 dBm RF output, and -148 dBm sensitivity.

Operating Conditions:

• Supply voltage: 1.8–3.7 V
• Operating temperature: -40 to +85 °C
• Frequency range: 137 MHz to 1020 MHz

Absolute Maximum Ratings:

• Max supply voltage: 3.9 V
• Max junction/storage temperature: -55 to +150 °C

Key Specs:

• Frequency Range: 137 MHz to 1020 MHz
• LoRa™ Sensitivity: -148 dBm
• Maximum RF Output Power: +20 dBm (100 mW)
• LoRa™ RX Current: 9.9 mA (Typ)
• Register Retention Current: 200 nA (Typ)
• Programmable Bit Rate: up to 300 kbps
• Frequency Synthesizer Resolution: 61 Hz
• Maximum Link Budget: 168 dB

Features:

• LoRa™ Modem
• 168 dB maximum link budget
• +20 dBm - 100 mW constant RF output vs. V supply
• High sensitivity: down to -148 dBm
• Low RX current of 9.9 mA, 200 nA register retention
• FSK, GFSK, MSK, GMSK, LoRa™ and OOK modulation
• Built-in temperature sensor and low battery indicator

Applications:

• Automated Meter Reading.
• Home and Building Automation.
• Wireless Alarm and Security Systems.
• Industrial Monitoring and Control
• Long range Irrigation Systems

Package:

• QFN 28 Package
• Wafer Form

• LoRa TM Modem
• 168 dB maximum link budget
• +20 dBm - 100 mW constant RF output vs. V supply
• +14 dBm high efficiency PA
• Programmable bit rate up to 300 kbps
• High sensitivity: down to -148 dBm
• Bullet-proof front end: IIP3 = -11 dBm
• Excellent blocking immunity
• Low RX current of 9.9 mA, 200 nA register retention
• Fully integrated synthesizer with a resolution of 61 Hz
• FSK, GFSK, MSK, GMSK, LoRa TM and OOK modulation
• Built-in bit synchronizer for clock recovery
• Preamble detection
• 127 dB Dynamic Range RSSI
• Automatic RF Sense and CAD with ultra-fast AFC
• Packet engine up to 256 bytes with CRC
• Built-in temperature sensor and low battery indicator

• Automated Meter Reading.

• Home and Building Automation.

• Wireless Alarm and Security Systems.

• Industrial Monitoring and Control

• Long range Irrigation Systems

• Section Section Page

• 1. General Description................................................................................................................................................. 9

• 1.1. Simplified Block Diagram................................................................................................................................. 9

• 1.2. Product Versions ............................................................................................................................................10

• 1.3. Pin Diagram ................................................................................................................................................... 10

• 1.4. Pin Description ...............................................................................................................................................11

• 1.5. Package Marking ...........................................................................................................................................12

• 1. Electrical Characteristics ....................................................................................................................................... 13

• 2.1. ESD Notice .................................................................................................................................................... 13

• 2.2. Absolute Maximum Ratings ........................................................................................................................... 13

• 2.3. Operating Range............................................................................................................................................ 13

• 2.4. Thermal Properties ........................................................................................................................................ 13

• 2.5. Chip Specification ..........................................................................................................................................14

• 2.5.1. Power Consumption.................................................................................................................................. 14

• 2.5.2. Frequency Synthesis................................................................................................................................. 14

• 2.5.3. FSK/OOK Mode Receiver .........................................................................................................................16

• 2.5.4. FSK/OOK Mode Transmitter ..................................................................................................................... 17

• 2.5.5. Electrical Specification for LoRaTM Modulation ........................................................................................19

• 2.5.6. Digital Specification ...................................................................................................................................22

• 1. SX1276/77/78/79 Features.................................................................................................................................... 23

• 3.1. LoRaTM Modem............................................................................................................................................ 24

• 3.2. FSK/OOK Modem.......................................................................................................................................... 24

• 1. SX1276/77/78/79 Digital Electronics ..................................................................................................................... 25

• 4.1. The LoRaTM Modem..................................................................................................................................... 25

• 4.1.1. Link Design Using the LoRaTM Modem ....................................................................................................26

• 4.1.2. LoRaTM Digital Interface ...........................................................................................................................34

• 4.1.3. Operation of the LoRaTM Modem............................................................................................................. 36

• 4.1.4. Frequency Settings ...................................................................................................................................37

• 4.1.5. Frequency Error Indication........................................................................................................................ 37

• 4.1.6. LoRaTM Modem State Machine Sequences .............................................................................................38

• 4.1.7. Modem Status Indicators........................................................................................................................... 46

• 4.2. FSK/OOK Modem.......................................................................................................................................... 46

• 4.2.1. Bit Rate Setting ......................................................................................................................................... 46

• 4.2.2. FSK/OOK Transmission............................................................................................................................ 47

• 4.2.3. FSK/OOK Reception ................................................................................................................................. 48

• 4.2.4. Operating Modes in FSK/OOK Mode........................................................................................................ 54

• 4.2.5. Startup Times ............................................................................................................................................56

• 4.2.6. Receiver Startup Options .......................................................................................................................... 59

• 4.2.7. Receiver Restart Methods......................................................................................................................... 60

• 4.2.8. Top Level Sequencer ................................................................................................................................ 61

DATASHEET

• Section Page
• 4.2.9. Data Processing in FSK/OOK Mode......................................................................................................... 65
• 4.2.10. FIFO ........................................................................................................................................................66
• 4.2.11. Digital IO Pins Mapping ...........................................................................................................................69
• 4.2.12. Continuous Mode ....................................................................................................................................70
• 4.2.13. Packet Mode ........................................................................................................................................... 71
• 4.2.14. io-homecontrol® Compatibility Mode ...................................................................................................... 79
• 4.3. SPI Interface ..................................................................................................................................................80
• SX1276/77/78/79 Analog & RF Frontend Electronics............................................................................................ 81
• 5.1. Power Supply Strategy .................................................................................................................................. 81
• 5.2. Low Battery Detector ..................................................................................................................................... 81
• 5.3. Frequency Synthesis ..................................................................................................................................... 81
• 5.3.1. Crystal Oscillator ....................................................................................................................................... 81
• 5.3.2. CLKOUT Output........................................................................................................................................ 82
• 5.3.3. PLL............................................................................................................................................................ 82
• 5.3.4. RC Oscillator ............................................................................................................................................. 82
• 5.4. Transmitter Description ..................................................................................................................................83
• 5.4.1. Architecture Description ............................................................................................................................ 83
• 5.4.2. RF Power Amplifiers.................................................................................................................................. 83
• 5.4.3. High Power +20 dBm Operation ............................................................................................................... 84
• 5.4.4. Over Current Protection ............................................................................................................................85
• 5.5. Receiver Description...................................................................................................................................... 85
• 5.5.1. Overview ................................................................................................................................................... 85
• 5.5.2. Receiver Enabled and Receiver Active States.......................................................................................... 85
• 5.5.3. Automatic Gain Control In FSK/OOK Mode.............................................................................................. 85
• 5.5.4. RSSI in FSK/OOK Mode........................................................................................................................... 86
• 5.5.5. RSSI and SNR in LoRaTM Mode.............................................................................................................. 87
• 5.5.6. Channel Filter ............................................................................................................................................ 88
• 5.5.7. Temperature Measurement....................................................................................................................... 89
• Description of the Registers................................................................................................................................... 90
• 6.1. Register Table Summary............................................................................................................................... 90
• 6.2. FSK/OOK Mode Register Map .......................................................................................................................93
• 6.3. Band Specific Additional Registers.............................................................................................................. 106
• 6.4. LoRaTM Mode Register Map....................................................................................................................... 108
• Application 116
• Information ........................................................................................................................................ 7.1. Crystal Resonator Specification................................................................................................................... 116
• 7.2. Reset of the Chip ......................................................................................................................................... 116
• 7.2.1. POR......................................................................................................................................................... 116
• 7.2.2. Manual Reset ..........................................................................................................................................117
• 7.3. Top Sequencer: Listen Mode Examples...................................................................................................... 117

DATASHEET

• Section Page
• 7.3.1. Wake on Preamble Interrupt ................................................................................................................... 117
• 7.3.2. Wake on SyncAddress Interrupt ..............................................................................................................120
• 7.4. Top Sequencer: Beacon Mode ....................................................................................................................123
• 7.4.1. Timing diagram........................................................................................................................................ 123
• 7.4.2. Sequencer Configuration......................................................................................................................... 123
• 7.5. Example CRC Calculation ...........................................................................................................................125
• 7.6. Example Temperature Reading ...................................................................................................................126
• 1. Packaging Information......................................................................................................................................... 128
• 8.1. Package Outline Drawing ............................................................................................................................ 128
• 8.2. Recommended Land Pattern....................................................................................................................... 129
• 8.3. Tape & Reel Information.............................................................................................................................. 130
• 8.4. Wafer Delivery ............................................................................................................................................. 130

DATASHEET

• Section Page
• Table 1. SX1276/77/78/79 Device Variants and Key Parameters .................................................................................10
• Table 2. Pin Description ................................................................................................................................................11
• Table 3. Absolute Maximum Ratings .............................................................................................................................13
• Table 4. Operating Range .............................................................................................................................................13
• Table 5. Thermal Properties ..........................................................................................................................................13
• Table 6. Power Consumption Specification ...................................................................................................................14
• Table 7. Frequency Synthesizer Specification ..............................................................................................................14
• Table 8. FSK/OOK Receiver Specification ....................................................................................................................16
• Table 9. Transmitter Specification .................................................................................................................................17
• Table 10. LoRa Receiver Specification .........................................................................................................................19
• Table 11. Digital Specification .......................................................................................................................................22
• Table 12. Example LoRaTM Modem Performances, 868MHz Band .............................................................................25
• Table 13. Range of Spreading Factors ..........................................................................................................................27
• Table 14. Cyclic Coding Overhead ................................................................................................................................27
• Table 15. LoRa Bandwidth Options ...............................................................................................................................28
• Table 16. LoRaTM Operating Mode Functionality .........................................................................................................36
• Table 17. LoRa CAD Consumption Figures ..................................................................................................................45
• Table 18. DIO Mapping LoRaTM Mode .........................................................................................................................46
• Table 19. Bit Rate Examples .........................................................................................................................................47
• Table 20. Preamble Detector Settings ...........................................................................................................................53
• Table 21. RxTrigger Settings to Enable Timeout Interrupts ..........................................................................................54
• Table 22. Basic Transceiver Modes ..............................................................................................................................54
• Table 23. Receiver Startup Time Summary ..................................................................................................................57
• Table 24. Receiver Startup Options 25. Sequencer States ..........................................................................................................................................61 ..............................................................................................................................60
• Table
• Table 26. Sequencer Transition Options .......................................................................................................................62
• Table 27. Sequencer Timer Settings .............................................................................................................................63
• Table 28. Status of FIFO when Switching Between Different Modes of the Chip .........................................................67
• Table 29. DIO Mapping, Continuous Mode ...................................................................................................................69
• Table 30. DIO Mapping, Packet Mode ..........................................................................................................................69
• Table 31. CRC Description ...........................................................................................................................................77
• Table 32. Frequency Bands ..........................................................................................................................................82
• Table 33. Power Amplifier Mode Selection Truth Table ................................................................................................83
• Table 34. High Power Settings ......................................................................................................................................84
• Table 35. Operating Range, +20dBm Operation ...........................................................................................................84
• Table 36. Operating Range, +20dBm Operation ...........................................................................................................84
• Table 37. Trimming of the OCP Current ........................................................................................................................85
• Table 39. RssiSmoothing Options .................................................................................................................................86

DATASHEET

• Section Page
• Table 40. Available RxBw Settings ................................................................................................................................88
• Table 41. Registers Summary .......................................................................................................................................90
• Table 42. Register Map .................................................................................................................................................93
• Table 43. Low Frequency Additional Registers ...........................................................................................................106
• Table 44. High Frequency Additional Registers ..........................................................................................................107
• Table 45. Crystal Specification ....................................................................................................................................116
• Table 46. Listen Mode with PreambleDetect Condition Settings .................................................................................119
• Table 47. Listen Mode with PreambleDetect Condition Recommended DIO Mapping ...............................................119
• Table 48. Listen Mode with SyncAddress Condition Settings .....................................................................................122
• Table 49. Listen Mode with PreambleDetect Condition Recommended DIO Mapping ...............................................122
• Table 50. Beacon Mode Settings ................................................................................................................................124
• Table 51. Revision History ...........................................................................................................................................131

DATASHEET

• Section Page
• Figure 1. Block Diagram .................................................................................................................................................9
• Figure 2. Pin Diagrams .................................................................................................................................................10
• Figure 3. Marking Diagram ...........................................................................................................................................12
• Figure 4. SX1276/77/78/79 Block Schematic Diagram ................................................................................................23
• Figure 5. LoRaTM Modem Connectivity .......................................................................................................................26
• Figure 6. LoRaTM Packet Structure .............................................................................................................................29
• Figure 7. Interrupts Generated in the Case of Successful Frequency Hopping Communication. ................................33
• Figure 8. LoRaTM Data Buffer .....................................................................................................................................34
• Figure 9. LoRaTM Modulation Transmission Sequence. .............................................................................................38
• Figure 10. LoRaTM Receive Sequence. ......................................................................................................................39
• Figure 11. LoRaTM CAD Flow .....................................................................................................................................43
• Figure 12. CAD Time as a Function of Spreading Factor .............................................................................................44
• Figure 13. Consumption Profile of the LoRa CAD Process ..........................................................................................45
• Figure 14. OOK Peak Demodulator Description ...........................................................................................................49
• Figure 15. Floor Threshold Optimization ......................................................................................................................50
• Figure 16. Bit Synchronizer Description .......................................................................................................................51
• Figure 17. Startup Process ...........................................................................................................................................56
• Figure 18. Time to RSSI Sample ..................................................................................................................................57
• Figure 19. Tx to Rx Turnaround ...................................................................................................................................58
• Figure 20. Rx to Tx Turnaround ...................................................................................................................................58
• Figure 21. Receiver Hopping ........................................................................................................................................59
• Figure 22. Transmitter Hopping ....................................................................................................................................59
• Figure 23. Timer1 and Timer2 Mechanism ...................................................................................................................63
• Figure 24. Sequencer State Machine ...........................................................................................................................64
• Figure 25. SX1276/77/78/79 Data Processing Conceptual View .................................................................................65
• Figure 26. FIFO and Shift Register (SR) ......................................................................................................................66
• Figure 27. FifoLevel IRQ Source Behavior ...................................................................................................................67
• Figure 28. Sync Word Recognition ...............................................................................................................................68
• Figure 29. Continuous Mode Conceptual View ............................................................................................................70
• Figure 30. Tx Processing in Continuous Mode .............................................................................................................70
• Figure 31. Rx Processing in Continuous Mode ............................................................................................................71
• Figure 32. Packet Mode Conceptual View ...................................................................................................................72
• Figure 33. Fixed Length Packet Format .......................................................................................................................73
• Figure 34. Variable Length Packet Format ...................................................................................................................74
• Figure 35. Unlimited Length Packet Format .................................................................................................................74
• Figure 36. Manchester Encoding/Decoding .................................................................................................................78
• Figure 37. Data Whitening Polynomial .........................................................................................................................79
• Figure 38. SPI Timing Diagram (single access) ...........................................................................................................80
• Figure 39. TCXO Connection .......................................................................................................................................81

Table 2 Pin Description

DATASHEET

WIRELESS, SENSING & TIMING

Stresses above the values listed below may cause permanent device failure. Exposure to absolute maximum ratings for extended periods may affect device reliability.

Table 3 Absolute Maximum Ratings

Note Specific ratings apply to +20 dBm operation (see Section 5.4.3).

Table 5 Thermal Properties

DATASHEET

The SX1276/77/78/79 is available in a 28-lead QFN package as shown in Figure 57.

Figure 57. Package Outline Drawing

DATASHEET