LAN8720 Network Ethernet Transceiver Module

LAN8720 Network Ethernet Transceiver Module is a high-performance, low-power physical layer (PHY) transceiver that brings robust 10/100 Mbps Ethernet connectivity to embedded systems. This module utilizes the compact LAN8720A IC, enabling microcontrollers and specialized processors to achieve reliable network communication with minimal external components. Consequently, designers can dramatically reduce board space and system complexity. The module supports both RMII (Reduced Media Independent Interface) and MII, though RMII is commonly used for its lower pin count, making it ideal for resource-constrained devices like Arduino, Raspberry Pi Pico, and STM32 boards. Therefore, you should choose the LAN8720 module for applications demanding high-speed, standards-compliant, and energy-efficient wired networking.

Key Features:

• High-Speed Transceiver: Supports IEEE 802.3 standards for both 10BASE-T and 100BASE-TX (Fast Ethernet) operation, automatically negotiating the fastest connection.
• Low Power Consumption: Features an integrated power-saving mode, which significantly reduces current draw when the link is inactive or during low-power operation.
• RMII Interface: The module primarily uses the 50 MHz Reduced Media Independent Interface, which requires fewer GPIO pins on the host microcontroller than MII.
• Integrated LDO: Includes an internal LDO regulator, allowing the device to operate efficiently from a single 3.3 V supply rail.
• Link and Activity LEDs: Provides dedicated status pins for link detection and network activity, offering vital diagnostic feedback to the user.

Technical Specifications:

• Data Rate Support: 10 Mbps and 100 Mbps (Full and Half Duplex)
• Interface: Reduced Media Independent Interface (RMII)
• Supply Voltage (Core): 1.2 V (Internal LDO)
• Supply Voltage (I/O): 3.3 V (±5%)
• Clock Requirement: Requires an external 50 MHz clock source for RMII operation, typically provided by the host MCU or an on-board crystal oscillator.
• Operating Temperature Range: −40°C to +85°C (Industrial Grade)
• Current Consumption: ≈ 120 mA (Active, 100BASE-TX)

Mechanical Specifications:

• Component IC: Microchip LAN8720A
• Connector: Standard RJ45 socket with integrated magnetics
• Mounting: PCB module with 2.54 mm (0.1 in) pin headers for breadboard or through-hole mounting.
• Magnetics: Includes integrated transformer and common mode choke for EMI suppression and isolation.

Dimensions:

• Module Board Size: ≈ 53 mm x 17 mm
• Pin Header Pitch: 2.54 mm
• RJ45 Port Height: Standard
• Weight: ≈ 6 g (Lightweight for portable applications)

Pinout and Wiring:

• VCC: Connect to 3.3 V power supply (Main I/O voltage).
• GND: Connect to the circuit ground reference.
• RST (Reset): Active low reset signal. Drive low to reset the PHY.
• CLK/XTAL1: Input for the required 50 MHz reference clock signal for RMII operation.
• TX_EN: Transmit Enable. Controls the start of the transmit process.
• TXD0/TXD1: Transmit Data lines (D0 and D1) for transferring data to the Ethernet network.
• RXD0/RXD1: Receive Data lines (D0 and D1) for receiving data from the Ethernet network.
• CRS_DV: Carrier Sense/Data Valid. Indicates when the PHY is receiving valid data.
• MDIO/MDC: Management Data Input/Output and Management Data Clock. Used for configuring and reading the PHY’s internal registers.

Datasheet Reference:

• Download Microchip LAN8720A Ethernet PHY Datasheet

Commonly Used in:

• Microcontroller Boards: Providing core Ethernet capability to powerful ARM microcontrollers, such as STM32, ESP32, and PIC32 series.
• Internet of Things (IoT) Gateways: It forms the wired backbone for industrial and commercial IoT edge devices.
• Single Board Computers (SBCs): Used as the physical layer interface for network ports on custom or simplified SBC designs.

Applications:

• Industrial Automation: Facilitating Modbus/TCP or EtherNet/IP communication in factory environments.
• Networked Sensors: Establishing reliable connectivity for remote monitoring and data acquisition systems.
• Embedded Web Servers: Allowing devices to host configuration and data pages over a local network.
• Network Test Equipment: Used in small-scale network analyzers and debugging tools.

Equivalent Models:

• KSZ8081RND (Microchip): A single-supply, low-power 10/100BASE-T PHY with RMII support, offering comparable features and performance.
• DP83848 (Texas Instruments): An alternative, highly robust 10/100 Mbps Ethernet PHY, however, it generally requires an MII interface setup.
• RTL8201F (Realtek): Another single-chip Fast Ethernet PHY that supports both MII and RMII, providing a functional cross-reference option.

Package Includes:

• 1 x LAN8720 Network Ethernet Transceiver Module