LAN8742AI-CZ Industrial Ethernet PHY

ElecSuppliers Part Number GuideSep 06, 2026

LAN8742AI-CZ is a Microchip Technology 10/100 Ethernet physical layer transceiver designed for embedded systems that need a compact and flexible wired network interface. It supports both 10BASE-T and 100BASE-TX communication and connects to an Ethernet MAC through either the reduced-pin-count RMII interface or the conventional MII interface.

As the industrial-temperature version of the LAN8742A family, LAN8742AI-CZ operates from -40°C to +85°C. Its small 24-pin SQFN package, flexible I/O supply and integrated power-management functions make it well suited to space-constrained industrial and embedded networking designs.

10BASE-T and 100BASE-TX Connectivity

LAN8742AI-CZ integrates a complete single-channel Ethernet PHY for Fast Ethernet applications. It supports 10 Mbps 10BASE-T and 100 Mbps 100BASE-TX operation with full-duplex communication.

The device complies with the relevant IEEE 802.3 and IEEE 802.3u Ethernet requirements and includes auto-negotiation. This allows the PHY to determine the appropriate link speed and duplex mode with a connected Ethernet device without requiring extensive software configuration.

Automatic polarity detection and correction further simplify the physical Ethernet interface.

RMII Interface for Embedded Processors

The LAN8742AI-CZ is particularly useful in microcontroller and processor-based designs because it supports RMII. Compared with a conventional MII connection, RMII reduces the number of signals required between the Ethernet MAC and PHY.

The PHY can also operate through the MII interface when a host processor requires a conventional Ethernet MAC connection. This interface flexibility allows the same LAN8742A family to be considered across different embedded hardware architectures.

For designs where PCB routing and processor pin count are important constraints, the RMII option can significantly simplify the Ethernet portion of the board.

flexPWR Architecture

LAN8742AI-CZ incorporates Microchip's flexPWR technology to provide flexible power-management options. Its LVCMOS I/O voltage can be configured across approximately 1.8V to 3.3V, allowing the PHY to interface with processors operating at different logic levels.

An integrated 1.2V regulator reduces the requirement for an additional external regulator in appropriate designs. The device also provides several low-power modes for applications where the Ethernet interface does not need to remain fully active at all times.

The flexible supply architecture allows LAN8742AI-CZ to be integrated into systems using a single 3.3V supply while maintaining compatibility with lower-voltage digital logic.

HP Auto-MDIX and Network Diagnostics

HP Auto-MDIX is integrated into the LAN8742AI-CZ Ethernet interface. This function allows the PHY to automatically detect the required transmit and receive pair configuration, reducing concerns about whether a connected cable is wired as straight-through or crossover.

Cable diagnostic support can provide additional information about the condition of the Ethernet connection. Together with link-status monitoring and automatic polarity correction, these functions can simplify troubleshooting during equipment installation and maintenance.

Wake-on-LAN Support

LAN8742AI-CZ includes physical-layer Wake-on-LAN functionality. The device can monitor Ethernet traffic for configured wake-up conditions, including supported wake-up frames and magic packets.

This capability is useful for systems that need to reduce power consumption while retaining network-based wake-up functionality. Industrial controllers, embedded computers and network-connected instruments can use this feature as part of a broader system power-management strategy.

Industrial Temperature and Compact Package

The industrial LAN8742Ai version is specified for operation from -40°C to +85°C. This temperature range makes LAN8742AI-CZ more appropriate for equipment installed in environments with wider temperature fluctuations than standard commercial Ethernet designs.

The device uses a 24-pin SQFN/VQFN package with a footprint of approximately 4 mm × 4 mm. The compact package helps reduce PCB area while integrating the Ethernet physical-layer functions, power management and network interface features required by embedded applications.

The LAN8742AI-CZ ordering code corresponds to the tray-packaged industrial-temperature device. Tape-and-reel versions use a different ordering suffix.

Clock and Hardware Integration

LAN8742AI-CZ can use a low-cost 25 MHz crystal, helping reduce the external component count in compact Ethernet designs. The PHY also includes an integrated power-on reset function and configuration straps that allow important operating parameters to be established during hardware initialization.

Two status LED outputs are available for displaying Ethernet link and activity information. These outputs can be connected directly to front-panel or board-level indicators where visual network status is required.

Applications for LAN8742AI-CZ

LAN8742AI-CZ can be used in networked industrial controllers, embedded computers, test instruments, network printers, servers, set-top boxes and other products requiring 10/100 Mbps Ethernet connectivity.

Its combination of industrial temperature operation, RMII support, flexible I/O voltage and low-power functions is especially suitable for microcontroller-based products where board space and power consumption need to be controlled.

For embedded Ethernet designs using a processor with an integrated MAC, LAN8742AI-CZ provides the physical-layer interface between the digital system and the external twisted-pair Ethernet network while keeping the overall PHY implementation compact.