Microchip LAN9352 Guide: The 2-Port Managed Ethernet Switch with PTP

In the industrial connectivity market, one digit makes all the difference.

If you are looking for the industry-standard EtherCAT slave controller, you might have landed here searching for the LAN9252. However, if you are looking for a robust Managed Ethernet Switch to daisy-chain industrial IoT devices or add ports to a microcontroller, you have found the right chip: the Microchip LAN9352.

This guide clears up the confusion between these two sibling chips and dives deep into the capabilities of the LAN9352, a powerhouse for IEEE 1588 precision timing and industrial switching.

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Table of Contents

1. The Critical Distinction: LAN9352 vs. LAN9252
2. Technical Specifications: LAN9352 at a Glance
3. Software & Integration: Linux & Harmony
4. Hardware Design: Interfaces & Power
5. Key Applications
6. Conclusion

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1. The Critical Distinction: LAN9352 vs. LAN9252

Before we talk about what the LAN9352 is, we must clarify what it is not.

Feature	Microchip LAN9352	Microchip LAN9252
Primary Function	Managed Ethernet Switch	EtherCAT Slave Controller (ESC)
Protocol Focus	Generic Ethernet, PROFINET, Modbus	EtherCAT
Hardware	Switch Fabric, IEEE 1588 PTP Unit	FMMUs, SyncManagers, Distributed Clock
Typical Use	IoT Gateways, Daisy-Chaining Devices	Motor Drives, I/O Modules

The Verdict:

• Buy LAN9252 if you are building an EtherCAT Slave device to connect to a Beckhoff PLC.
• Buy LAN9352 if you need to add extra Ethernet ports to your MCU, support ring topologies (RSTP), or require precision time synchronization (PTP) for general industrial ethernet.

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2. Technical Specifications: LAN9352 at a Glance

The LAN9352 is designed to sit between your microcontroller (MCU) and the physical network, handling all the heavy switching logic.

Core Features

• 2-Port PHY + 1 Virtual Port: It integrates two physical 10/100 transceivers (PHYs) and one internal port that connects to your host MCU. This effectively gives your single-port MCU a 3-port switch fabric.
• IEEE 1588v2 PTP: Hardware-based timestamping allows for sub-microsecond synchronization accuracy. It supports Transparent Clock (TC) and Ordinary Clock modes, critical for coordinating motion control or sensor arrays.
• VLAN & QoS: Supports up to 16 VLAN groups and 4 priority queues per port, allowing you to prioritize critical control data over bulk traffic.

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3. Software & Integration: Linux & Harmony

Microchip provides robust software support, ensuring you aren't writing drivers from scratch.

MPLAB Harmony

If you are using a PIC32 or SAM MCU, the LAN9352 is supported natively in MPLAB Harmony v3.

• TCP/IP Stack: The "Net" package includes drivers that treat the LAN9352 as a network interface.
• Virtual PHY: A clever feature where the switch presents itself to the MCU as a single PHY. This allows standard MAC drivers to work with the switch without complex modification.

Linux Support

For MPU-based designs, the LAN9352 is supported via DSA (Distributed Switch Architecture) drivers.

• This exposes each port of the switch as a separate network interface (e.g., eth0, eth1) in Linux, allowing you to use standard tools like bridge-utils or iproute2 to configure VLANs and forwarding.

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4. Hardware Design: Interfaces & Power

The LAN9352 offers extreme flexibility in how it connects to your host processor.

Host Interfaces

1. HBI (Host Bus Interface): A high-speed 8-bit or 16-bit parallel bus (SRAM-like). Best for high-throughput data transfer.
2. SPI / SQI: Serial Peripheral Interface (up to Quad SPI). Perfect for low-pin-count microcontrollers where you don't have enough pins for a parallel bus.
3. I2C: Primarily for management/configuration if the data path is handled elsewhere (less common).

Package & Power

• Packages: Available in 72-pin QFN (compact) and 80-pin TQFP (easier to solder).
• Supply: Requires a single 3.3V rail. An internal regulator generates the required 1.2V core voltage.
• Fiber Optic: Native support for 100BASE-FX means you can connect fiber transceivers directly for long-distance, noise-immune links.

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5. Key Applications

Industrial Daisy-Chaining

In a factory, running a "Home Run" cable from every sensor back to the server room is expensive. The LAN9352 allows devices to be daisy-chained (Linear Topology). Data hops from device A to B to C, saving miles of cabling.

VoIP Phones

A VoIP phone needs two ports: one to the wall (Upstream) and one to the PC (Downstream). The LAN9352 handles this traffic separation and QoS internally.

Test & Measurement

The IEEE 1588 PTP feature allows distributed test equipment to trigger measurements at the exact same nanosecond, even if they are hundreds of meters apart.

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6. Conclusion

The Microchip LAN9352 is the Swiss Army Knife of industrial Ethernet. It solves the problem of adding robust, managed switching and precision timing to any embedded design without the complexity of a high-end processor. Just remember: if your spec sheet says "EtherCAT," double-check that you don't actually need its cousin, the LAN9252.

Sourcing Microchip Ethernet ICs Need to build a prototype? Visit Aichiplink.com to search for stock of the LAN9352 and the LAN9252 EtherCAT Controller.

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Written by Jack Elliott from AIChipLink.

 

AIChipLink, one of the fastest-growing global independent electronic   components distributors in the world, offers millions of products from thousands of manufacturers, and many of our in-stock parts is available to ship same day.

 

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