SX1278

LoRa Transceiver

The SX1278 is a lora transceiver from Semtech. View the full SX1278 datasheet below including key specifications, absolute maximum ratings.

Official SX1278 datasheet (PDF) — the source this page was extracted from.

Manufacturer

Semtech

SX1278 Key Specifications

Parameter	Value
Case/Package	VQFN
China RoHS	Compliant
Current - Receiving	10.8mA ~ 12mA
Current - Receiving	12 mA
Current - Transmitting	20mA ~ 120mA
Current - Transmitting	120 mA
Data Rate	300 kbps
Data Rate (Max)	300kbps
DigiKey Programmable	Not Verified
Frequency	137MHz ~ 525MHz
Frequency	525 MHz
GPIO	6
Height - Seated (Max)	1 mm
Interface	SPI
Introduction Date	2013-10-30
Lead Free	Lead Free
Length	6 mm
Lifecycle Status	Production (Last Updated: 1 month ago)
Max Operating Temperature	85 °C
Min Operating Temperature	-40 °C
Modulation	FSK, GFSK, GMSK, MSK, OOK
Mounting Type	Surface Mount
Nominal Supply Voltage (DC)	3.3 V
Number of Circuits	1
Number of GPIO	6
Number of Pins	28
Number of Terminals	28
Operating Temperature	-40°C ~ 85°C
Package / Case	28-VQFN Exposed Pad
Packaging	MouseReel
Packaging	Tape & Reel (TR)
Power - Output	20dBm
Protocol	LoRa™
REACH SVHC	Unaffected
RF Family/Standard	802.15.4
RoHS	Compliant
Sensitivity	-148dBm
Sensitivity (dBm)	-148 dBm
Serial Interfaces	SPI
Standard Pack Qty	3000
Supplier Device Package	28-QFN (6x6)
Temperature Grade	Industrial
Terminal Pitch	650 µm
Type	TxRx Only
Supply Voltage	1.8V ~ 3.7V
Width	6 mm

SX1278 Overview

Part: SX1278IMLTRT — Semtech

Type: Sub-GHz LoRa / (G)FSK / OOK Transceiver

Description: Low-power long-range transceiver (SX1276/77/78/79 family) covering 137–1020 MHz, with LoRa modem, sensitivity down to -148 dBm, +20 dBm PA, 168 dB maximum link budget and programmable bit rate up to 300 kbps.

Operating Conditions:

Operating temperature: -40 to +85 °C (QFN-28 package operating range)
Frequency range: 137–1020 MHz (family)
Bit rate: up to 300 kbps

Absolute Maximum Ratings:

Max supply voltage (VDDmr): 3.9 V (min -0.5 V)
Storage/ambient temperature (Tmr): -55 to +115 °C
Max junction temperature (Tj): +125 °C
Max RF input level (Pmr): +10 dBm

Key Specs:

Sensitivity: down to -148 dBm (LoRa)
Maximum link budget: 168 dB
RF output power: up to +20 dBm (100 mW, constant vs. supply voltage); +14 dBm high-efficiency PA
RX current: 9.9 mA; 200 nA register retention
Bit rate: programmable up to 300 kbps
IIP3: -11 dBm
RSSI dynamic range: 127 dB
Synthesizer resolution: 61 Hz

Features:

LoRa modem with long-range spread-spectrum communication
FSK, GFSK, MSK, GMSK, LoRa and OOK modulation
Built-in bit synchronizer for clock recovery and preamble detection
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
Excellent blocking immunity
Supports WMBus and IEEE 802.15.4g in (G)FSK modes

Applications:

Automated meter reading
Home and building automation
Wireless alarm and security systems
Industrial monitoring and control
Long-range irrigation systems

Package:

QFN-28 (tape & reel, 3000 pieces MOQ; Pb-free, halogen-free, RoHS/WEEE compliant)

SX1278 Features

LoRa® 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® 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

SX1278 Applications

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

DATASHEET

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 LoRa Modulation............................................................................................. 19
2.5.6. Digital Specification................................................................................................................................... 22
1. SX1276/77/78/79 Features.................................................................................................................................... 23
3.1. LoRa® Modem............................................................................................................................................... 24
3.2. FSK/OOK Modem.......................................................................................................................................... 24
1. SX1276/77/78/79 Digital Electronics ..................................................................................................................... 25
4.1. Link Design The LoRa® Modem........................................................................................................................................ Using the LoRa® Modem 25 ......................................................................................................26
4.1.1. 4.1.2. LoRa® Digital Interface .............................................................................................................................34
4.1.3. Operation of the LoRa® Modem ............................................................................................................... 36
4.1.4. Frequency Settings ................................................................................................................................... 36
4.1.5. Frequency Error Indication........................................................................................................................ 37
4.1.6. LoRa AFC.................................................................................................................................................. 37
4.1.7. Digital IO Pin Mapping............................................................................................................................... 45
4.1.8. Modem Status Indicators........................................................................................................................... 46
4.2. FSK/OOK Modem.......................................................................................................................................... 46 46
4.2.1. Bit Rate Setting .........................................................................................................................................
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. 60
Receiver Restart Methods.........................................................................................................................

DATASHEET

Section Section Page
4.2.8. Top Level Sequencer ................................................................................................................................ 61
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
1. 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 LoRa Mode................................................................................................................... 87
5.5.6. Channel Filter............................................................................................................................................ 88
5.5.7. Temperature Measurement....................................................................................................................... 89
1. 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. LoRa Mode Register Map............................................................................................................................ 108
1. Application Information ........................................................................................................................................ 116
7.1. Crystal Resonator Specification................................................................................................................... 116
7.2. Reset of the Chip ......................................................................................................................................... 116
7.2.1. POR......................................................................................................................................................... 116

7.2.2. Manual Reset 117

DATASHEET

Section Page
7.3. Top Sequencer: Listen Mode Examples...................................................................................................... 7.3.1. Wake on Preamble Interrupt ................................................................................................................... 7.3.2. Wake on SyncAddress Interrupt ..............................................................................................................120 7.4. Top Sequencer: Beacon Mode ....................................................................................................................123 7.4.1. Timing diagram........................................................................................................................................ 7.4.2. Sequencer Configuration......................................................................................................................... 7.5. Example CRC Calculation ........................................................................................................................... 7.6. Example Temperature Reading ...................................................................................................................126 Packaging Information......................................................................................................................................... 117 117 123 123 125
1. 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 LoRa® 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. LoRa® Operating Mode Functionality ...........................................................................................................36
Table 17. LoRa CAD Consumption Figures ..................................................................................................................45
Table 18. DIO Mapping LoRa® 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 ..............................................................................................................................60
Table 25. Sequencer States ..........................................................................................................................................61
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
1. Power Amplifier Mode Selection Truth Table ................................................................................................83
Table
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
1. 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

SX1278 Pin Configuration

Table 2 Pin Description

Number	Name SX1276/77/79/(78)	Type SX1276/77/79/(78)	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

Table 2 Pin Description

DATASHEET

SX1278 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 3.4.3).

SX1278 Thermal Information

Table 5 Thermal Properties

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

Table 5 Thermal Properties

DATASHEET

SX1278 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

Variants on the same datasheet

These parts have exact links to the same datasheet. They are candidates to compare, not verified drop-in replacements; check package, pinout and electrical limits.

Part Number	Manufacturer	Package
SX1276IMLTRT	Semtech	28-VQFN Exposed Pad
SX1277IMLTRT	Semtech	28-VQFN Exposed Pad
SX1278IMLTRT	Semtech	28-VQFN Exposed Pad
SX1279IMLTRT	Semtech	28-VQFN Exposed Pad

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