KSZ9031RNXIA-TR Gigabit Ethernet PHY with RGMII Timing Control

ElecSuppliers Part Number GuideSep 06, 2026

The KSZ9031RNXIA-TR is a triple-speed Ethernet physical layer transceiver from Microchip Technology for embedded systems requiring 10Mbps, 100Mbps and 1000Mbps networking. It connects to an Ethernet MAC through an RGMII interface and is designed for applications where Gigabit performance, PCB flexibility and reliable network diagnostics are important.

The industrial-grade variant operates across a -40°C to +85°C temperature range and uses a compact 48-pin QFN package.

RGMII Interface for Gigabit Ethernet

KSZ9031RNXIA-TR supports 10BASE-T, 100BASE-TX and 1000BASE-T over standard twisted-pair Ethernet connections. Auto-negotiation allows the PHY to select the appropriate link speed and duplex mode according to the connected network.

Its RGMII interface provides a compact connection between the PHY and Ethernet MAC. The device includes programmable pad-skew controls for RGMII clock, control and data signals, allowing transmit and receive timing to be adjusted during board design and system bring-up.

This timing flexibility can be particularly useful when PCB trace lengths, MAC timing characteristics or board routing constraints make fixed RGMII delay difficult to achieve.

Programmable RGMII Timing

A major feature of the KSZ9031 family is its fine-grained RGMII timing adjustment. The PHY provides independent skew controls for RGMII transmit and receive signals, with approximately 0.06ns adjustment steps for the relevant pad-skew settings.

This allows designers to tune the relationship between clock and data signals without relying entirely on PCB trace delays. Such control can simplify Gigabit Ethernet layout and provide additional margin when optimizing signal timing.

The device also supports RGMII timing configurations suited to different MAC implementations, making it adaptable to a wide range of embedded Ethernet architectures.

Integrated Ethernet Diagnostics

KSZ9031RNXIA-TR includes LinkMD time-domain reflectometry for copper cable diagnostics. The function can help identify cable-related problems by analyzing the Ethernet physical connection.

Additional diagnostic and test functions include loopback operation, NAND tree testing and PHY register access through the MDC/MDIO management interface. Automatic MDI/MDI-X crossover also allows the PHY to detect and correct pair swapping during Ethernet connection.

These features are useful during product development, manufacturing tests and field troubleshooting.

Simplified Gigabit Ethernet Hardware

The KSZ9031RNXIA-TR integrates termination functions for the differential Ethernet pairs, helping reduce the number of external components around the PHY.

The device also includes an LDO controller that can work with an external FET to generate the 1.2V core supply from a 3.3V source. Its I/O architecture supports the voltage levels required by different Ethernet MAC implementations.

Power-down and power-saving modes provide additional flexibility for systems that need to reduce energy consumption when the Ethernet interface is not active.

Industrial Temperature 48-QFN Package

The KSZ9031RNXIA-TR is specified for operation from -40°C to +85°C, making it suitable for industrial environments where commercial-temperature Ethernet PHYs may not provide sufficient operating margin.

The 48-pin QFN package measures approximately 7mm × 7mm, allowing the PHY to fit into compact embedded networking boards while maintaining triple-speed Ethernet capability.

The -TR suffix identifies the tape-and-reel packaging option, which is intended for automated surface-mount assembly.

KSZ9031RNXIA-TR for Embedded Networking

With Gigabit Ethernet support, programmable RGMII timing, integrated termination and cable diagnostics, the KSZ9031RNXIA-TR is suited to embedded networking equipment that needs more timing flexibility than a basic Ethernet PHY.

Typical applications include industrial controllers, gateways, network appliances, embedded computers, Ethernet communication modules and other systems requiring 10/100/1000Mbps copper Ethernet in an industrial temperature range.