Elecrow LR2021 LoRa Module-150-960MHz Sub-GHz Full-Band LoRa Module

Model LMM16121D

The LR2021 is a high-performance multiband wireless transceiver module based on Semtech's fourth-generation LoRa® IP. The module integrates the LR2021 RF transceiver chip, a 32 MHz industrial-grade TCXO, SIMO/LDO power management, an SPI control interface, and separate low- and high-frequency antenna ports. It supports Sub-GHz, 2.4 GHz ISM, and licensed S-Band frequencies, making it suitable for terrestrial networks and satellite IoT communications.

The module uses a 10 mm × 10 mm × 2.5 mm 20-pin SMT castellated package and is suitable for applications requiring a compact form factor, low power consumption, and multiregional deployment, including smart metering, asset tracking, industrial IoT, smart homes, smart cities, and satellite IoT.

Features

• Multiband connectivity: Sub-GHz coverage from 150–960 MHz, 2.4 GHz ISM coverage from 2400–2483 MHz, and support for S-Band satellite communication frequencies.
• High link budget: Sub-GHz receive sensitivity as low as -141.5 dBm (LoRa SF12, 125 kHz), maximum transmit power of +22 dBm, and a typical link budget of up to 163.5 dB.
• High-speed wireless transmission: FLRC data rates of up to 2.6 Mbps for OTA updates, image transmission, and reporting edge-computing results.
• Low power consumption: Typical chip-level sleep current of 0.47 µA without data retention and typical Sub-GHz receive current of 5.7 mA in non-boosted gain mode.
• Dual antenna ports: ANT_LF for 150–960 MHz; ANT_HF for 2.4 GHz ISM and S-Band. Both ports are designed for 50 Ω systems.
• Multiple modulation schemes: Supports modulation schemes including LoRa, (G)FSK, OOK, O-QPSK, LR-FHSS, FLRC, DBPSK, and BLE 5.0 PHY.
• Multiprotocol compatibility: Supports protocol ecosystems including LoRa/LoRaWAN®, Amazon Sidewalk, Sigfox, Wi-SUN, Wireless M-Bus, Z-Wave, BLE 5.0 PHY, and IEEE 802.15.4 (Thread/Zigbee).
• Long-range communication: The specifications indicate a typical Sub-GHz line-of-sight communication range exceeding 15 km and up to 68 km in open environments when using a high-gain antenna. Actual range depends on the frequency band, data rate, antenna, terrain, interference, and regulatory restrictions.
• Industrial operating temperature: -40°C to +85°C.
• Compact package: 10 mm × 10 mm × 2.5 mm, 20-pin SMT castellated package with a 1.27 mm pin pitch.

:::note Specific protocol features, frequency-band compliance, and available transmit power depend on the host software, antenna design, and regulatory requirements of the deployment region. :::

Applications

• Smart electricity, water, gas, and heat meters
• Global logistics, land and sea transportation, and valuable asset tracking
• Predictive maintenance of industrial equipment, factory environmental monitoring, and Mesh networks
• Smart home gateways, border routers, and end nodes
• Smart city applications such as streetlights, waste bins, geomagnetic parking detection, and environmental sensing
• LEO satellite IoT terminals for marine, desert, and emergency scenarios
• Mesh intercoms, drone data transmission, and wearable device synchronization

System Overview

The LR2021 module is built around the Semtech LR2021 RF transceiver and integrates an RF front-end matching network, a 32 MHz TCXO, and power decoupling and management circuitry. The host MCU controls the module through the SPI interface and uses signals such as BUSY, NRESET, DIO5, DIO6, and TX/RX_EN for status monitoring, interrupts, reset, and RF front-end control.

The module has independent low- and high-frequency transceiver channels: ANT_LF corresponds to the Sub-GHz channel, while ANT_HF corresponds to the 2.4 GHz ISM and S-Band channels.

Specification

The following parameters were tested at VDD = 3.3 V, an ambient temperature of 25°C, and with a 32 MHz TCXO reference clock.

Parameter Category	Parameter	Specification
Chip and Hardware	Main chip	Semtech LR2021 fourth-generation LoRa transceiver
Chip and Hardware	Operating voltage	1.8–3.7 V, 3.3 V typical
Chip and Hardware	Operating temperature	-40 to +85°C
Chip and Hardware	Package dimensions	10 mm × 10 mm × 2.5 mm, 20-pin SMT castellated package
Chip and Hardware	Reference clock	32 MHz industrial-grade TCXO
Chip and Hardware	Antenna ports	ANT_LF + ANT_HF, 50 Ω
RF Transmit	Maximum Sub-GHz transmit power	+22 dBm
RF Transmit	Maximum 2.4 GHz transmit power	+12 dBm
RF Transmit	Transmit power dynamic range	32 dB, in 0.5 dB steps
RF Receive	Sub-GHz receive sensitivity	-141.5 dBm @ LoRa SF12 / BW 125 kHz
RF Receive	2.4 GHz receive sensitivity	-103 dBm @ O-QPSK 250 kbps DSSS
RF Receive	Typical link budget	163.5 dB
Modulation	Supported modulation schemes	LoRa, (G)FSK, OOK, O-QPSK, LR-FHSS, FLRC, DBPSK, BLE 5.0 PHY
Modulation	LoRa spreading factors	SF5–SF12
Data Rate	LoRa	0.0458–125 kbps
Data Rate	FLRC	Up to 2.6 Mbps
Operating Band	Sub-GHz	150–960 MHz
Operating Band	2.4 GHz ISM	2400–2483 MHz
Operating Band	Licensed S-Band	1900–2200 MHz (satellite communications)
Digital Interface	Control interface	SPI, up to 16 MHz; digital I/O
Data Buffer	FIFO	Separate transmit/receive FIFOs

Hardware Overview

Pinout

The LR2021 uses a 20-pin SMT castellated package. The top-view pin locations and signal groupings are shown below.

Pin Definitions

Pin	Name	Type	Description
P1	VDD	Power	3.3 V power input; parallel 47 µF, 10 µF, and 100 nF decoupling capacitors are recommended
P2	LR_NSS	Input	SPI chip select, active low
P3	LR_SCK	Input	SPI clock
P4	LR_MOSI	Input	SPI data input, host to module
P5	LR_MISO	Output	SPI data output, module to host
P6	GND	Power	System ground
P7	DIO6	Input/Output	Configurable as IRQ, RF_SWITCH, GPIO, HF_CLK_OUT, or TX/RX_TRIGGER
P8	DIO5	Input/Output	Configurable as IRQ, RF_SWITCH, GPIO, HF_CLK_OUT, or TX/RX_TRIGGER; pulled up by default after reset
P9	LR_BUSY	Output	Busy status indicator; high indicates that the module is processing a command
P10	LR_NRESET	Input	Active-low reset; hold low for at least 100 µs
P11	ANT_LF	RF Input/Output	150–960 MHz low-frequency antenna port, 50 Ω
P12	GND	Power	System ground
P13	GND	Power	System ground
P14	GND	Power	System ground
P15	TX/RX_EN	Input/Output	External RF switch or FEM control; may also be used as a general-purpose control signal
P16	NC	-	No connection
P17	ANT_HF	RF Input/Output	2.4 GHz ISM and S-Band high-frequency antenna port, 50 Ω
P18	GND	Power	System ground
P19	GND	Power	System ground
P20	GND	Power	System ground
P21–P24	GND	Power	Ground pads on the bottom of the module; connect to the main ground plane using multiple ground vias

Electrical Characteristics

Absolute Maximum Ratings

:::warning Exceeding the absolute maximum ratings may cause permanent damage to the device. Prolonged operation near these limits may reduce device reliability and service life. :::

Symbol	Parameter	Minimum	Typical	Maximum	Unit
VDDmr	Supply voltage	-0.5	-	3.9	V
Tmr	Temperature	-55	-	125	°C
Pmr	Maximum RF port input power	-	-	+10	dBm

Recommended Operating Conditions

Symbol	Parameter	Minimum	Typical	Maximum	Unit
VCC	Supply voltage	1.8	3.3	3.7	V
Top	Operating temperature	-40	-	+85	°C
Tmaxj	Maximum junction temperature	-	-	105	°C
Clop	Digital port load capacitance	-	-	20	pF
VSWR	Standing-wave ratio for guaranteed PA stability	-	-	10:1	-

Power Consumption

Mode	Condition	Typical	Unit
Sleep	No data retention, no RTC	0.47	µA
Sleep	Data retention, no RTC	0.57	µA
Sleep	Data retention, RTC enabled	1.4	µA
Standby RC	Internal 32 MHz RC oscillator enabled	1.21	mA
Standby XOSC	32 MHz crystal/TCXO enabled	1.79	mA
Frequency Synthesis	915 MHz	3	mA
Receive Sub-GHz	Non-boosted gain	5.7	mA
Transmit Sub-GHz	+22 dBm	105	mA
Transmit Sub-GHz	+17 dBm	43	mA
Transmit Sub-GHz	+14 dBm	27	mA
Transmit Sub-GHz	+10 dBm	17	mA
Transmit 2.4 GHz	+12 dBm	23	mA

Mechanical Characteristics

The module measures 10 mm × 10 mm with a typical thickness of 2.5 mm; the peripheral castellated pins have a pitch of 1.27 mm. The recommended pads should match the module pins, and a ground pad should be provided beneath the module to improve RF grounding and heat dissipation.

Recommended PCB Layout

• ANT_LF and ANT_HF traces should be as short as possible and maintain a 50 Ω characteristic impedance.
• Do not place copper pours or signal traces beneath the antenna and RF trace areas; reserve an RF keepout area.
• Power-supply decoupling capacitors should be placed close to VDD, with leads and return paths kept as short as possible.
• The RF matching network should follow the Semtech reference design, with L/C components placed close to the corresponding RF ports.
• The ground pad beneath the module should be connected to the main ground plane using multiple vias to reduce ground impedance and improve heat dissipation.
• SPI, reset, and status signals between the host and the module should not run parallel to RF traces over long distances.

Getting Started

1. Hardware Requirements

• 1 LR2021 module
• 1 host MCU supporting 3.3 V logic levels
• A regulated 3.3 V power supply with sufficient headroom for peak transmit current
• A 50 Ω antenna and matching network for the target frequency band
• An SPI interface and at least 4 control/status GPIOs
• An oscilloscope, logic analyzer, or current analyzer for prototype debugging (optional)

2. Connect the Host MCU

At a minimum, the host must connect the following signals:

LR2021 Signal	Host Connection	Description
VDD	3.3 V	47 µF + 10 µF + 100 nF decoupling capacitors placed near the module are recommended
GND	GND	Reliably ground all GND pins and bottom ground pads
LR_NSS	SPI CS	Active low
LR_SCK	SPI SCK	SPI clock up to 16 MHz
LR_MOSI	SPI MOSI	Host transmits, module receives
LR_MISO	SPI MISO	Module transmits, host receives
LR_BUSY	GPIO input	Do not send new commands while high
LR_NRESET	GPIO output	Active-low reset; hold low for at least 100 µs
DIO5 / DIO6	GPIO input/output	Configure as interrupt, RF switch, or trigger signals according to the firmware
TX/RX_EN	GPIO or external FEM	May be configured for the application when no external RF switch is used

3. Connect the Antennas

• For Sub-GHz operation, connect a 150–960 MHz 50 Ω antenna or matching network to ANT_LF.
• For 2.4 GHz or S-Band operation, connect a 50 Ω antenna or matching network for the corresponding frequency band to ANT_HF.
• When routing both frequency bands on the same PCB, ensure that the two RF traces are isolated from each other to prevent coupling.
• Do not transmit at high power without an appropriate load or antenna connected.

4. Power-on Checklist

1. Before applying power, confirm that VDD does not exceed 3.7 V and check for shorts between the power supply and ground.
2. Confirm that ANT_LF and ANT_HF are not interchanged and that the connected antennas cover the target frequency bands.
3. Pull LR_NRESET low for at least 100 µs, then release it.
4. Wait for LR_BUSY to be released before sending initialization commands over SPI.
5. First verify SPI, reset, interrupt, and frequency configurations at low transmit power, then gradually increase the power.
6. Use a spectrum analyzer or calibrated receiver to confirm that the center frequency, output power, and modulation parameters comply with local regulations.

:::note Module register commands, driver APIs, and LoRaWAN protocol stack integration should follow the Semtech LR2021 datasheet and corresponding software package. :::

Reference Design

A typical application includes a 3.3 V power input, an SPI control interface, DIOs, dual antenna connections, and RF port protection. The following reference design is provided with the module documentation.

Observe the following design considerations:

• 47 µF, 10 µF, and 100 nF multistage decoupling is recommended at the VDD input.
• The reference design uses 470 Ω series resistors on the SPI and certain control lines to suppress reflections and EMI; actual resistance values should be determined based on the host drive capability, trace length, and signal-integrity testing.
• LR_NRESET should be pulled up to VDD through a 100 kΩ resistor.
• ANT_LF and ANT_HF should each use a 50 Ω matching network designed for the target frequency band.
• Low-parasitic TVS/ESD devices may be added to the RF ports; their impact on insertion loss and impedance matching must be evaluated during component selection.

Resources

Product

• LR2021 LoRa Module Product Page

Hardware Files

• [Eagle_SCH&PCB] LR2021 V0.2 Reference Schematic

Related Documents

• Semtech LR2021 Datasheet Rev. 1.1
• LoRaWAN® Regional Parameters v1.0.3
• AN1200.102 LR2021 TCXO Temperature Compensation Application Note

Revision History

Date	Version	Description
2026-10-08	V1.0	Initial Wiki version compiled from the LR2021 module specifications, schematic, and PCB documentation

Tech Support and Product Discussion

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