The KSZ9897RTXI is a highly integrated IEEE 802.3-compliant Layer 2 managed Gigabit Ethernet switch that combines a 7-port switch, five integrated 10BASE-Te/100BASE-TX/1000BASE-T PHYs, and two configurable MAC interfaces. The device supports RGMII, MII, and RMII interfaces, allowing flexible connection to host processors, controllers, Ethernet switches, or external PHY devices.

Designed for high-performance networking applications, the KSZ9897RTXI features wire-speed Gigabit switching, VLAN, QoS, ACL filtering, traffic prioritization, and Spanning Tree support. It also provides flexible management through SPI, I²C, and MIIM interfaces, enabling easy configuration of PHY, MAC, and switch functions.

KSZ9897RTXI is well suited for industrial Ethernet switches, automation systems, embedded gateways, and other advanced networking applications.

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Technical Specifications

Core Features

• Switch Management Capabilities

- 10/100/1000Mbps Ethernet switch basic functions: frame buffer management, address look-up table, queue management, MIB counters

- Non-blocking store-and-forward switch fabric assures fast packet delivery by utilizing 4096 entry forwarding table with 256kByte frame buffer

- Jumbo packet support up to 9000 bytes

- Port mirroring/monitoring/sniffing: ingress and/or egress traffic to any port

- MIB counters for fully-compliant statistics gathering 34 counters per port

- Tail tagging mode (one byte added before FCS) support at host port to inform the processor which ingress port receives the packet and its priority

- Loopback modes for remote failure diagnostics

- Rapid spanning tree protocol (RSTP) support for topology management and ring/linear recovery

- Multiple spanning tree protocol (MSTP) support

• Five Integrated PHY Ports

- 1000BASE-T/100BASE-TX/10BASE-Te IEEE 802.3

- Fast Link-up option significantly reduces link-up time

- Auto-negotiation and Auto-MDI/MDI-X support

- On-chip termination resistors and internal biasing for differential pairs to reduce power

- LinkMD® cable diagnostic capabilities for determining cable opens, shorts, and length

• Two Configurable External MAC Ports

- Reduced Gigabit Media Independent Interface

(RGMII) v2.0

- Reduced Media Independent Interface (RMII) v1.2 with 50MHz reference clock input/output option

- Media Independent Interface (MII) in PHY/MAC mode

• Advanced Switch Capabilities

- IEEE 802.1Q VLAN support for 128 active VLAN groups and the full range of 4096 VLAN IDs

- IEEE 802.1p/Q tag insertion/removal on per port basis

- VLAN ID on per port or VLAN basis

- IEEE 802.3x full-duplex flow control and half-duplex back pressure collision control

- IEEE 802.1X access control (Port-based and MAC address based)

- IGMP v1/v2/v3 snooping for multicast packet filtering

- IPv6 multicast listener discovery (MLD) snooping

- IPv4/IPv6 QoS support, QoS/CoS packet prioritization

- 802.1p QoS packet classification with 4 priority queues

- Programmable rate limiting at ingress/egress ports

- Broadcast storm protection

- Four priority queues with dynamic packet mapping for IEEE 802.1p, IPv4 DIFFSERV, IPv6 Traffic Class

- MAC filtering function to filter or forward unknown unicast, multicast and VLAN packets

- Self-address filtering for implementing ring topologies

• Comprehensive Configuration Registers Access

- High-speed 4-wire SPI (up to 50MHz), I2C interfaces provide access to all internal registers

- MII Management (MIIM, MDC/MDIO 2-wire) Interface provides access to all PHY registers

- In-band management via any of the data ports

- I/O pin strapping facility to set certain register bits from I/O pins at reset time

- On-the-fly configurable control registers

• Power Management

- Energy detect power-down mode on cable disconnect

- Dynamic clock tree control

- Unused ports can be individually powered down

- Full-chip software power-down

- Wake-on-LAN (WoL) standby power mode with PME interrupt output for system wake upon triggered events

Highlights

l  Non-blocking wire-speed Ethernet switching fabric

l  Full-featured forwarding and filtering control, including Access Control List (ACL) filtering

l  Full VLAN and QoS support

l  Five ports with integrated 10/100/1000BASE-T PHY transceivers

l  Two ports with 10/100/1000 Ethernet MACs and configurable RGMII/MII/RMII interfaces

l  IEEE 802.1X access control support

l  EtherGreen™ power management features, including low power standby

l  Flexible management interface options: SPI, I2C, MIIM, and in-band management via any port

l  Commercial/Industrial temperature range support

l  128-pin TQFP-EP (14 x 14mm) RoHS compliant pkg

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Pin Configurations

Internal Block Diagram & System Architecture

The KSZ9897RTXI features a highly integrated hardware architecture consisting of port transceiver units, a switch engine, and supporting functional modules. It integrates five 10/100/1000 Mbps PHYs for Ports 1–5, each paired with an independent GMAC for Ethernet frame processing. Additionally, GMAC6 and GMAC7 provide external Gigabit MAC interfaces supporting RGMII, MII, and RMII, enabling flexible connection with host processors or external PHY devices.

At the center of the device, the Switch Engine manages packet forwarding, QoS, and traffic scheduling through modules such as the Address Lookup Engine, Frame Buffer, MIB Counters, and Queue Management. Device configuration is performed through control registers via SPI, I²C, or MIIM interfaces, allowing adjustment of network parameters including port settings, VLAN, and QoS. With integrated Gigabit PHYs, flexible MAC expansion, and advanced Layer 2 switching capabilities, the KSZ9897RTXI is ideal for industrial Ethernet switches, embedded gateways, and high-performance networking systems.

Hardware Design Considerations

When designing with the KSZ9897RTXI, several key hardware considerations should be followed:

Power Supply Design: Use separate core, I/O, and analog power rails with proper decoupling. Isolate the analog supply from the digital 3.3V rail to minimize noise and place decoupling capacitors close to each power pin.

Clock and Reset: Use a 25 MHz crystal with high frequency accuracy and ensure the RESET_N signal remains low for the required delay after power-up.

Ethernet Differential Routing: Route MDI differential pairs with controlled impedance, matched lengths, and adequate ESD protection to maintain signal integrity.

RGMII Interface Layout: Follow the recommended impedance and termination requirements, and ensure proper clock delay or length matching based on the selected RGMII timing mode.

Strap Pin Configuration: Configure all strap pins with dedicated pull-up or pull-down resistors before reset to ensure the device enters the correct operating mode.

PCB Layout and Thermal Design: A 4-layer PCB is recommended. Separate digital and chassis ground where required, and connect the exposed thermal pad to the ground plane using thermal vias for effective heat dissipation.

TSN and AVB Microarchitecture Management

The KSZ9897RTXI integrates TSN (Time-Sensitive Networking) and AVB (Audio Video Bridging) hardware features to deliver deterministic, low-latency, and highly reliable Ethernet communication. It supports 8 hardware priority queues per port, along with SP/WRR scheduling, CBS and TAS traffic shaping, and IEEE 802.1CB FRER for redundant frame transmission, ensuring efficient handling of real-time industrial and multimedia traffic. The KSZ9897RTXI-TR, which uses the same device specifications with a tape-and-reel packaging option, is suitable for automated SMT production environments requiring high-volume assembly.

For precise network synchronization, the device includes a hardware timestamp engine and an IEEE 802.1AS-compatible RTC, enabling accurate PTP/gPTP time synchronization with nanosecond-level precision. To achieve optimal TSN performance, engineers should use high-speed management interfaces such as SPI or RGMII, configure hardware timestamping, and properly allocate buffer resources to ensure reliable real-time data transmission. The KSZ9897RTXI-TR provides the same TSN and AVB capabilities while offering packaging flexibility for industrial networking applications.

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Typical Applications

With advanced Layer 2 switching features, multiple Gigabit ports, VLAN/QoS support, and flexible management interfaces, KSZ9897RTXIcan meet the requirements of various high-performance networking applications.

1. Stand-alone 10/100/1000 Mbps Ethernet Switches

The KSZ9897RTXI integrates five Gigabit PHY ports and advanced switching functions, making it suitable for standalone Ethernet switch designs. It supports wire-speed data forwarding, VLAN configuration, QoS management, and traffic prioritization to provide efficient and reliable network connections in enterprise and industrial environments.

2. VoIP Infrastructure Switches

For Voice over IP (VoIP) networks, low latency and stable data transmission are essential. The KSZ9897RTXI supports QoS and traffic classification features to prioritize voice packets, helping reduce delay, jitter, and packet loss for improved voice communication quality.

3. Broadband Gateways and Firewalls

The device can be integrated into broadband gateways, routers, and firewall systems that require multiple Ethernet connections. Its flexible MAC interfaces allow connection with processors or external network devices, while Layer 2 management features support efficient traffic control and network configuration.

4. Wi-Fi Access Points

The KSZ9897RTXI is suitable for high-performance Wi-Fi access points that require Ethernet backhaul connectivity. Its Gigabit switching capability provides fast data transfer between wireless modules, processors, and wired networks, supporting stable communication in high-bandwidth applications.

5. Integrated DSL/Cable Modems

In DSL and cable modem systems, the Ethernet switch helps manage data communication between the modem controller and connected devices. The KSZ9897RTXI provides reliable Gigabit Ethernet connectivity with low-latency switching and flexible interface options for system integration.

6. Security and Surveillance Systems

Modern IP surveillance systems require stable transmission of high-resolution video streams. With Gigabit switching performance, QoS support, and reliable packet handling, the KSZ9897RTXI is well suited for IP cameras, NVR systems, and security networking equipment.

7. Industrial Control and Automation Switches

Designed for industrial networking applications, the KSZ9897RTXI supports reliable Ethernet communication in factory automation, PLC networks, and machine control systems. Its industrial temperature option, advanced traffic management, and robust Layer 2 features help ensure stable operation in demanding environments.

8. Networked Measurement and Control Systems

The KSZ9897RTXI can be used in distributed measurement and control systems that require real-time data exchange between multiple devices. Its low-latency switching, VLAN support, and flexible management interfaces enable efficient communication in industrial monitoring and embedded network applications.

Package Information

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