SX1276WS

Low Power Long Range Transceiver

The SX1276WS is a low power long range transceiver from Semtech. View the full SX1276WS datasheet below including absolute maximum ratings.

Manufacturer

Semtech

Overview

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

Features

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

Applications

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

Pin Configuration

Table 2 Pin Description

Number	Name	Type	Description
0	GROUND	-	Exposed ground pad
1	RFI_LF	I	RF input for bands 2&3
2	VR_ANA	-	Regulated supply voltage for analogue circuitry
3	VBAT_ANA	-	Supply voltage for analogue circuitry
4	VR_DIG	-	Regulated supply voltage for digital blocks
5	XTA	I/O	XTAL connection or TCXO input
6	XTB	I/O	XTAL connection
7	NRESET	I/O	Reset trigger input
8	DIO0	I/O	Digital I/O, software configured
9	DIO1/DCLK	I/O	Digital I/O, software configured
10	DIO2/DATA	I/O	Digital I/O, software configured
11	DIO3	I/O	Digital I/O, software configured
12	DIO4	I/O	Digital I/O, software configured
13	DIO5	I/O	Digital I/O, software configured
14	VBAT_DIG	-	Supply voltage for digital blocks
15	GND	-	Ground
16	SCK	I	SPI Clock input
17	MISO	O	SPI Data output
18	MOSI	I	SPI Data input
19	NSS	I	SPI Chip select input
20	RXTX/RF_MOD	O	Rx/Tx switch control: high in Tx
21	RFI_HF (GND)	I (-)	RF input for band 1 (Ground)
22	RFO_HF (GND)	O (-)	RF output for band 1 (Ground)
23	GND	-	Ground
24	VBAT_RF	-	Supply voltage for RF blocks
25	VR_PA	-	Regulated supply for the PA
26	GND	-	Ground
27	PA_BOOST	O	Optional high-power PA output, all frequency bands
28	RFO_LF	O	RF output for bands 2&3

DATASHEET

WIRELESS, SENSING & TIMING

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 3 Absolute Maximum Ratings

Symbol	Description	Min	Max	Unit
VDDmr	Supply Voltage	-0.5	3.9	V
Tmr	Temperature	-55	115	° C
Tj	Junction temperature	-	125	° C
Pmr	RF Input Level	-	10	dBm

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

Thermal Information

Table 5 Thermal Properties

Symbol	Description	Min	Typ	Max	Unit
THETA_JA	Package θ ja (Junction to ambient)	-	22.185	-	°C/W
THETA_JC	Package θ jc (Junction to case ground paddle)	-	0.757	-	°C/W

DATASHEET

Package Information

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

Figure 57. Package Outline Drawing

DATASHEET

Related Variants

The following components are covered by the same datasheet.

Part Number	Manufacturer	Package
SX1276	Semtech	—
SX1276/77/78/79	Semtech	—
SX1276/77/79	Semtech	—
SX1276IMLTRT	Semtech	28-VQFN Exposed Pad
SX1276MB1LAS	Semtech Corporation	Module
SX1276MB1MAS	Semtech Corporation	Module

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