LAN9353/PT - 3-Port 10/100 Managed Ethernet Switch | Microchip
MPN: LAN9353/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.4 | $340.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $2.84 | $2,840.00 |
LAN9353/PT Overview
An Ethernet switch is a Layer 2 networking device that connects multiple Ethernet segments, learning MAC addresses, forwarding frames based on destination lookup tables, and isolating collision domains. In embedded systems, an integrated multi-port switch like the LAN9353/PT replaces several discrete PHY/MAC pairs and an external switch ASIC, reducing BOM cost and PCB area. The LAN9353 family occupies the role of "managed switch IC" within the broader hierarchy: Ethernet switch -> network IC -> interface IC -> wired communication -> semiconductor. The "managed" designation means the switch supports configurable per-port features (VLAN, QoS, port mirroring) via SPI, I2C, or SMI management interfaces.
Key features include three integrated 10/100 PHYs with HP Auto-MDIX, support for both 10BASE-T and 100BASE-TX on each port, dual-port RMII or single MII/RMII/Turbo MII host interfaces, an integrated 1.5KB frame buffer, IEEE 802.1Q VLAN support with 16 VLAN groups, QoS with four priority queues per port, and programmable per-port LEDs. The device operates from a single 3.3V supply with integrated 1.2V LDO for core logic and supports industrial temperature grades via the LAN9353i variant.
The LAN9353/PT uses a cut-through or store-and-forward switching architecture with a 1.5KB shared packet buffer, supporting wire-speed non-blocking switching on all three ports. The integrated PHYs include baseline wander correction, adaptive equalization, and crosstalk cancellation for robust operation over CAT5 cable. The host interface flexibility (dual RMII + MII/Turbo MII) allows direct connection to microcontrollers, microprocessors, or application processors without an external MAC.
Typical applications include industrial Ethernet daisy-chains, building automation gateways, networked HVAC controllers, automotive infotainment rear-seat entertainment hubs, and embedded Linux platforms using processors that lack a built-in Ethernet switch. The compact TQFP-EP package enables use in space-constrained industrial and consumer products.
When designing with the LAN9353/PT, provide proper 50-ohm controlled-impedance routing for all differential Ethernet pairs, place the 25 MHz crystal or oscillator within 1 cm of the XI pin, and follow Microchip reference schematic and layout guidelines for RJ-45 magnetics integration. Industrial variants (LAN9353I/PT) extend the operating range to -40C to +85C.
This page synthesizes Microchip datasheet specs, current distributor pricing as of 2026-10-22, drop-in same-package alternatives, and practical design notes for engineers selecting a 3-port managed Ethernet switch.
Drop-in alternatives for LAN9353/PT — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LAN9353/PT (same form factor and footprint) — differing in Package, Operating Temperature, Supply Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LAN9353I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
LAN9353T/PT
✅ Drop-In📋 Reference alternative (not in catalog)
LAN9354/PT
✅ Drop-In📋 Reference alternative (not in catalog)
LAN9352I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
KSZ9477STXI
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →LAN9353/PT Specifications (manufacturer-published)
| Product Type | 3-Port 10/100 Managed Ethernet Switch |
| Number of Ports | 3 |
| Ethernet Speed | 10/100 Mbps |
| PHY Integration | 3 integrated 10/100 PHYs |
| MAC Integration | 3 integrated MACs |
| Host Interface | Dual RMII or single MII/RMII/Turbo MII |
| Management Interface | SPI, I2C, SMI |
| VLAN Support | IEEE 802.1Q, 16 VLAN groups |
| QoS Queues | 4 priority queues per port |
| Frame Buffer | 1.5 KB shared |
| Auto-MDIX | Yes (HP Auto-MDIX) |
| Supply Voltage | 3.3 V (single supply, integrated 1.2V LDO) |
| Operating Temperature | 0C to +70C (commercial); -40C to +85C (LAN9353I/PT industrial) |
| Package | 64-TQFP-EP, 10x10 mm |
| Mounting Type | Surface Mount |
| Power Dissipation | 1.148 W (max, per FindIC data) |
| RoHS Status | Compliant |
LAN9353/PT Interfaces & Connectors
LAN9353/PT exposes the following interfaces and connectors as published by the manufacturer: Ethernet, Power Input. Expansion header pinout, connector pin numbering, and electrical limits are defined in the manufacturer documentation.
| Ethernet | 10/100 Mbps |
| Power Input | 3.3 V (single supply, integrated 1.2V LDO) |
Refer to the manufacturer documentation for the full expansion header pinout and connector pin numbering.
Power & Thermal Characteristics
| Power Input | 3.3 V (single supply, integrated 1.2V LDO) |
| Operating Temperature | 0C to +70C (commercial); -40C to +85C (LAN9353I/PT industrial) |
| Power Consumption | 1.148 W (max, per FindIC data) |
Power input and thermal parameters for LAN9353/PT as published by the manufacturer.
Typical Applications
LAN9353/PT is suitable for 6 applications: Industrial Ethernet Daisy-Chain, Building Automation Gateway, Automotive Infotainment Rear-Seat Hub, Networked HVAC Controller, Embedded Linux Platform Ethernet Expansion, Networked Audio Distribution Node.
Industrial Ethernet Daisy-Chain
The LAN9353/PT's three 10/100 ports with integrated PHYs make it ideal for industrial daisy-chain topologies where multiple Ethernet devices connect in series, eliminating the need for an external switch. Its dual RMII host interface lets a process controller simultaneously act as a switch node and as a host for an HMI or PLC. The -40C to +85C variant (LAN9353I/PT) is preferred for factory floor and outdoor cabinet environments with wide thermal swings.
Recommended
Building Automation Gateway
The LAN9353/PT supports 802.1Q VLAN tagging with 16 VLAN groups, allowing building automation gateways to segment BACnet/IP, Modbus TCP, and HVAC traffic on isolated VLANs. Its four priority queues per port deliver QoS that is essential for latency-sensitive lighting and access-control traffic. The single 3.3V supply and integrated PHYs reduce BOM count in compact DIN-rail designs.
Recommended
Automotive Infotainment Rear-Seat Hub
The LAN9353/PT is well suited to rear-seat entertainment hubs that need to share a 100 Mbps link between two display pods and a head unit. The 1.5 KB shared frame buffer and 802.1Q VLAN support let audio and video streams be tagged for QoS prioritization. While the commercial grade limits in-cabin deployments, industrial (-40C to +85C) variants handle automotive thermal stress. The TQFP-EP package provides a ground pad for thermal dissipation in enclosed consoles.
Recommended
Networked HVAC Controller
The LAN9353/PT's three-port architecture enables HVAC controllers to act as a multi-drop fieldbus node: one port to the upstream controller, one port to the local sensor cluster, and one spare for service diagnostics. Its 25 MHz reference clock and integrated HP Auto-MDIX simplify installation with no crossover configuration. With 802.1Q VLANs, technicians can isolate diagnostic traffic from operational control traffic on the same physical plant.
Recommended
Embedded Linux Platform Ethernet Expansion
Embedded Linux boards based on STM32 or i.MX processors often need multiple Ethernet ports for management, control, and service networks. The LAN9353/PT attaches to the host via MII or dual RMII and adds 3 extra switch ports, which is faster and cheaper than cascading external PHYs. The 1.5 KB buffer is sufficient for Linux TCP/IP workloads at 100 Mbps. Linux driver support is available from Microchip and mainline kernel.
Recommended
Networked Audio Distribution Node
The LAN9353/PT's integrated QoS with four priority queues per port is well matched to Dante, AVB, or AES67 audio nodes that need deterministic bandwidth allocation. Its three ports allow star topology wiring: one uplink to the network, one to a wall-plate amplifier, and one spare for local diagnostics. Cut-through switching mode minimizes latency for 48 kHz audio streams.
Recommended
Recommended Products Summary
Engineering reference data for LAN9353/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LAN9353I/PT | LAN9353T/PT | LAN9354/PT | LAN9252I/PT | KSZ9477STXI |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-TQFP-EP (10x10) | 64-TQFP-EP (10x10) - same | 64-TQFP-EP (10x10) - same | 64-TQFP-EP (10x10) - same | 64-TQFP-EP (10x10) - same | TQFP-128 (different family) |
| Number of Ports | 3 | 3 | 3 | 4 | 2 | 7 |
| Host Interface | Dual RMII or MII/Turbo MII | Dual RMII or MII/Turbo MII | Dual RMII or MII/Turbo MII | Dual RMII or MII/Turbo MII | SPI-managed | SGMII/RGMII |
| Operating Temperature | 0C to +70C (commercial) | -40C to +85C (industrial) | 0C to +70C | 0C to +70C | -40C to +85C | -40C to +85C |
| VLAN Groups | 16 (802.1Q) | 16 | 16 | 16 | 8 | 4096 (advanced) |
| Auto-MDIX | Yes (HP Auto-MDIX) | Yes | Yes | Yes | Yes | Yes |
| Supply Voltage | 3.3 V | 3.3 V | 3.3 V | 3.3 V | 3.3 V | 1.2 V / 3.3 V |
| Approx. Unit Price (1k qty, as of 2026-10-22) | USD 2.84 | USD 3.50 (industrial premium) | USD 2.84 | USD 3.30 | USD 2.50 | USD 7.20 |
Key Differentiators
- True 3-port managed switch with dual RMII host ports (vs LAN9252I/PT)
- MII/RMII host interface flexibility vs SPI-managed (vs LAN9252I/PT)
- Compact 64-TQFP-EP package across the family (vs KSZ9477STXI)
- Industrial temperature variant available in same package (vs LAN9353/PT (commercial only))
Design Notes
Route all Ethernet differential pairs with 100-ohm differential impedance and 50-ohm single-ended impedance on the outer layers. Keep trace length matching within 50 mils per pair. Place the RJ-45 magnetics module within 2 cm of the LAN9353/PT PHY outputs to minimize return loss. The exposed pad (EP) under the TQFP must be soldered to a continuous ground plane with multiple thermal vias for heat dissipation; otherwise the junction temperature will exceed the 70C ambient rating under full traffic load.
Provide 3.3V from a low-noise LDO or DC-DC with bulk and decoupling capacitors as recommended in the datasheet reference schematic. Place 10 uF bulk + 0.1 uF + 0.01 uF decoupling capacitor groups within 5 mm of each AVDD/VDD pin pair. Use a star-ground topology for analog and digital grounds, joined at the exposed pad. The integrated 1.2V LDO supplies the digital core; no external 1.2V rail is needed, but reserve a footprint for an external ferrite in case of supply noise issues.
Estimated: With 1.148 W max dissipation and the TQFP-EP package at approximately 25-30 C/W theta_JA (per typical 10x10 TQFP-EP datasheets), the junction would rise ~30C above ambient at full load - acceptable up to ~40C ambient for the commercial variant. Do not exceed the 25 MHz crystal or oscillator accuracy of +-50 ppm; MII/RMII timing margins are tight. Pull-up resistors are required on I2C and management interface lines even if not used at production. Finally, do not confuse LAN9353/PT (commercial) with LAN9353I/PT (industrial) when ordering - they look identical but differ in operating temperature grade.
When using the dual RMII host interface, ensure both RMII reference clocks are derived from the same 50 MHz source (typically from the LAN9353) to avoid inter-port timing skew. For MII or Turbo MII, the 25 MHz reference clock drives both the LAN9353 PHY and the host MAC; routing this clock trace with a ground reference and 50-ohm termination. Avoid long parallel runs between RMII data lines and the 25 MHz clock to minimize crosstalk into the high-speed data path.
Compliance Information
RoHS and REACH compliant per Microchip product page. AEC-Q100 not applicable - LAN9353/PT is commercial grade; LAN9353I/PT is industrial grade but not formally AEC-Q100 qualified. Contact Microchip for automotive-specific reliability data.
