LAN8742AI-CZ-TR Ethernet PHY for Embedded Networking

ElecSuppliers Part Number GuideSep 06, 2026

LAN8742AI-CZ-TR is a compact 10/100 Ethernet physical layer transceiver from Microchip designed to provide reliable Ethernet connectivity between a system MAC and a twisted-pair network. The device supports both 10BASE-T and 100BASE-TX operation and communicates with the host controller through the reduced-pin-count RMII interface.

With its small 24-pin SQFN package, flexible I/O voltage, integrated power management and industrial temperature range, LAN8742AI-CZ-TR fits applications where board space, power consumption and dependable Ethernet communication are important design considerations.

LAN8742AI-CZ-TR Ethernet Interface

The LAN8742AI-CZ-TR integrates the complete Ethernet PHY function required for 10 Mbps and 100 Mbps network communication. It supports IEEE 802.3 and IEEE 802.3u Ethernet standards and provides full-duplex operation.

The RMII interface reduces the number of connections between the Ethernet PHY and the host MAC compared with a traditional full MII interface. This makes the device suitable for embedded processors and microcontrollers where PCB routing resources are limited.

Auto-negotiation allows the PHY to determine the appropriate link speed and duplex configuration with the connected network device. Automatic polarity detection and correction further simplify Ethernet interface implementation.

Flexible Power and I/O Design

Power efficiency is one of the key characteristics of the LAN8742A family. LAN8742AI-CZ-TR supports an LVCMOS I/O voltage range from approximately 1.8 V to 3.3 V, allowing it to interface with different host processor architectures.

An integrated 1.2 V regulator helps reduce the need for additional external power circuitry. The device also incorporates several low-power operating modes for systems that need to reduce energy consumption during periods of limited network activity.

For designs using a single 3.3 V supply, the integrated power architecture can simplify the overall Ethernet hardware implementation.

HP Auto-MDIX and Cable Diagnostics

LAN8742AI-CZ-TR includes HP Auto-MDIX functionality, eliminating the need to manually distinguish between straight-through and crossover Ethernet cables in many system designs. This is particularly useful for embedded equipment that may be connected to different types of network infrastructure.

Cable diagnostic capability provides additional information about the physical Ethernet connection. Combined with link status monitoring and automatic polarity correction, these functions can help simplify network troubleshooting and improve system-level Ethernet management.

Industrial Temperature Operation

The “i” designation in LAN8742AI-CZ-TR identifies the industrial-temperature version of the LAN8742A family. It is specified for operation from -40°C to +85°C, making it suitable for equipment exposed to wider environmental temperature variations than standard commercial designs.

The device is supplied in a 24-pin SQFN/VQFN package measuring approximately 4 mm × 4 mm. The compact package is well suited to space-constrained networking boards while retaining the functions required for a complete 10/100 Ethernet PHY implementation.

Wake-on-LAN and System Power Management

LAN8742AI-CZ-TR includes Wake-on-LAN functionality that can support system designs requiring low-power standby states while maintaining the ability to detect network activity.

The PHY also provides link status change wake-up detection and an integrated power-on reset circuit. These features allow the Ethernet interface to be incorporated more closely into the system's overall power-management strategy rather than operating as a continuously active peripheral.

Typical LAN8742AI-CZ-TR Applications

LAN8742AI-CZ-TR can be used in embedded networking equipment, industrial controllers, networked printers, test and measurement instruments, telecom equipment and network-connected consumer electronics.

Its compact footprint also makes it suitable for designs such as wireless access points, digital video equipment, IP phones, routers and other products that require a 10/100 Ethernet connection without the size and complexity of a larger networking controller.

PCB Design Considerations

When designing with LAN8742AI-CZ-TR, the Ethernet differential signals should be routed carefully to maintain signal integrity. PCB layout should consider controlled impedance, trace symmetry, appropriate grounding and separation from noisy switching circuits.

The RMII clock and data connections between the PHY and host MAC should also be routed according to the timing requirements of the selected processor. Power supply decoupling should be positioned close to the relevant device pins, while the exposed package area and grounding arrangement should follow the manufacturer's layout recommendations.

For compact embedded Ethernet designs, LAN8742AI-CZ-TR combines 10/100 Mbps physical-layer connectivity, RMII operation, flexible I/O voltage, cable diagnostics, HP Auto-MDIX and low-power functions in a small industrial-temperature package.