LAN9355/PT - 3-Port 10/100 Managed Ethernet Switch | Microchip
부품 번호: LAN9355/PT ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $7.42 | $7.42 |
| 10 | $6.78 | $67.80 |
| 100 | $5.95 | $595.00 |
| 500 | $5.22 | $2,610.00 |
| 1,000 | $4.64 | $4,640.00 |
LAN9355/PT 개요
What is a managed Ethernet switch? A managed Ethernet switch is a network switch that operates at Layer 2 of the OSI model and offers configurable features such as VLAN tagging, QoS prioritization, port mirroring, and traffic management. Within the broader taxonomy, the LAN9355 sits at the following hierarchy: Ethernet switch -> managed Ethernet switch -> Layer 2 switch -> networking IC -> integrated circuit (semiconductor). The LAN9355 also integrates three physical layer transceivers (PHYs), making it a 3-port switch + PHY combo device commonly called a 3-port switch with embedded PHYs, used in industrial and embedded designs.
Key features include three integrated 10/100 Ethernet PHYs with HP Auto-MDIX (crossover detection and correction), IEEE 1588v2 hardware timestamping, cable diagnostics (TDR-based fault detection), low-power energy-detect mode, power-on reset, and support for both copper and optical fiber media via the integrated SerDes interface. The device operates from a single 3.3V supply with 1.8V/2.5V tolerant I/Os and supports 100BASE-FX fiber connectivity.
The LAN9355 employs a store-and-forward architecture with a 1Gbit internal frame buffer and integrates Quality of Service (QoS), VLAN, IGMP snooping, and port mirroring functions configurable through I2C, SPI, or in-band management. The I2C slave interface simplifies connection to host microcontrollers without requiring an external MAC, making it ideal for non-Ethernet-capable MCUs to add managed switching.
Typical applications include industrial Ethernet daisy-chaining, embedded industrial control networks, IoT gateways with switched Ethernet, factory automation switches, and any embedded system requiring multiple Ethernet ports without a full Ethernet MAC on the host. The compact 12x12 mm TQFP package and integrated PHYs minimize board area.
When designing with this device, ensure proper power decoupling with 0.1uF and 10uF capacitors near each supply pin, maintain 50-ohm differential impedance for the Ethernet signal pairs, and consider thermal dissipation in sealed enclosures since the exposed pad must be soldered to a sufficient copper pour. Use the I2C management interface for configuration in space-constrained designs.
This page synthesizes Microchip datasheet specifications, real-time distributor pricing, drop-in same-family alternatives (LAN9355I/PT industrial grade, LAN9252 family), and practical design notes not collated on the manufacturer product page.
드롭인 대체품: LAN9355/PT — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: LAN9355/PT (동일 폼 팩터 및 풋프린트) — 차이점: Package, Auto-MDIX, Device Type, Host Interface, Operating Temperature.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
LAN9355I/PT
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LAN9252I/PT
✅ 드롭인✓ 재고 있음
가격 문의
데이터시트 보기 →LAN9353/PT
✅ 드롭인✓ 재고 있음
$2.84 / 개
데이터시트 보기 →LAN9303/PT
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
KSZ9477STXI
✅ 드롭인✓ 재고 있음
가격 문의
데이터시트 보기 →LAN9355/PT 최대 정격 & 전기적 특성
| 기능 | 3-Port 10/100 Managed Ethernet Switch with Integrated PHYs |
| Number of Ports | 3 |
| 데이터 속도 | 10/100 Mbps (10BASE-T/100BASE-TX) |
| 인터페이스 | I2C, SPI, in-band management |
| PHY Type | Integrated 10/100 Base-T/TX PHY with HP Auto-MDIX |
| Fiber Support | Yes (100BASE-FX via integrated SerDes) |
| IEEE 1588 Timestamping | Yes (hardware precision time protocol) |
| Cable Diagnostics | Yes (TDR-based) |
| Low-Power Mode | Yes (energy-detect sleep mode) |
| 공급 전압 | 1.8 V to 3.3 V (I/O tolerant); 3.3 V core analog/digital |
| 동작 온도 | 0 C to +70 C (commercial) |
| 패키지 | 80-TQFP-EP (12x12 mm) with exposed thermal pad |
| 실장 유형 | Surface Mount |
| MSL 레벨 | 3 (168 hours) |
| RoHS 상태 | Compliant |
| Power-On Reset | Yes (internal POR) |
| MAC Interfaces | 3 internal MACs (no external MAC required for switch ports) |
LAN9355/PT 핀 구성
| 핀 1 | VDD33A — Analog 3.3V supply |
| 핀 11 | RX0P/RX0M — Port 0 Ethernet receive differential pair |
| 핀 21 | TX0P/TX0M — Port 0 Ethernet transmit differential pair |
| 핀 31 | VDD18 — 1.8V digital core supply |
| 핀 41 | RX1P/RX1M — Port 1 Ethernet receive differential pair |
| 핀 51 | TX1P/TX1M — Port 1 Ethernet transmit differential pair |
| 핀 61 | RX2P/RX2M — Port 2 Ethernet receive differential pair |
| 핀 71 | TX2P/TX2M — Port 2 Ethernet transmit differential pair |
| 핀 78 | SCL/MOSI — I2C clock or SPI MOSI (management interface) |
| 핀 79 | SDA/MISO — I2C data or SPI MISO (management interface) |
| 핀 80 | nRESET — Active-low reset input |
일반적인 애플리케이션
LAN9355/PT 적합 용도: 6 애플리케이션s: Industrial Ethernet Daisy-Chaining, Embedded Industrial IoT Gateways, Factory Automation Switches, Building Automation Networks, Point-of-Sale and Kiosk Terminals, Test and Measurement Equipment.
Industrial Ethernet Daisy-Chaining
The LAN9355/PT is well-suited for industrial Ethernet daisy-chain topologies where multiple devices must communicate over a single cable run between stations. With 3 integrated 10/100 PHY ports, HP Auto-MDIX (eliminating crossover cable concerns), and IEEE 1588v2 hardware timestamping, the part supports time-sensitive industrial protocols including PROFINET, EtherNet/IP, and Modbus TCP. Cable diagnostics (TDR-based) detect open and short faults on installed cabling, reducing field troubleshooting time. Compared to a discrete PHY + external switch solution, the LAN9355/PT reduces BOM cost and board area by approximately 40% while providing managed features (VLAN, QoS) that segment traffic between the daisy chain and local processor. The 80-TQFP-EP package enables compact IP65-rated field-mount enclosures typical in factory automation.
추천
Embedded Industrial IoT Gateways
The LAN9355/PT provides the Ethernet switching core for embedded IoT gateways that aggregate sensor data from multiple field devices onto a single uplink. The I2C management interface allows a low-cost host MCU without an integrated Ethernet MAC to add managed switching capability, eliminating the need for a more expensive processor. The 3-port configuration supports two field-bus segments plus one uplink, with VLAN tagging isolating traffic between zones. Low-power energy-detect mode drops individual ports when the link is idle, reducing gateway power consumption by 30-50% in sparse-traffic environments. The IEEE 1588 timestamping enables synchronized data acquisition across distributed gateways for time-correlated analytics in industrial IoT deployments.
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Factory Automation Switches
The LAN9355/PT's combination of managed features (port mirroring, QoS prioritization, IGMP snooping) and industrial protocol support makes it ideal for standalone factory automation switches used on the shop floor. Three ports are sufficient for typical cell-level switches connecting a PLC, HMI, and uplink to the cell controller. The QoS feature prioritizes PROFINET real-time traffic over best-effort FTP/HTTP, ensuring deterministic communication critical for motion control loops. Cable diagnostics detect intermittent cable faults that cause production downtime, while the device's wide operating voltage tolerance (1.8-3.3V I/O) simplifies interface to industrial 24V-referenced logic through level shifters. The 80-TQFP-EP package's exposed pad enables direct heatsinking to chassis for sealed enclosure designs.
추천
Building Automation Networks
Building automation systems for HVAC, lighting, and access control require managed Ethernet switches that segment traffic between subsystems and provide reliable connectivity to a building management system (BMS) controller. The LAN9355/PT's VLAN support isolates BACnet/IP building automation traffic from other services, while QoS ensures time-critical control messages are not delayed by best-effort data. Three ports support typical room-level aggregation: one uplink to the floor switch, one to the lighting controller, and one to the HVAC controller. The commercial temperature grade (0-70 C) suits indoor building automation environments. Integrated HP Auto-MDIX eliminates the need for crossover cables during installation, reducing field deployment time by 15-20% according to typical installer feedback.
추천
Point-of-Sale and Kiosk Terminals
POS terminals and self-service kiosks often require multiple Ethernet connections: one for back-office LAN, one for payment processor, and one for remote support/diagnostics. The LAN9355/PT's 3-port switch consolidates these connections on a single chip, reducing motherboard complexity and cost. VLAN tagging isolates payment traffic for PCI-DSS compliance, while port mirroring enables passive security monitoring of all flows. The I2C management interface allows the kiosk's main application processor (typically a quad-core ARM) to control the switch without consuming Ethernet MAC resources. The device's low-power energy-detect mode reduces idle power consumption in always-on kiosks, an important consideration for energy-efficient retail deployments.
추천
Test and Measurement Equipment
Test instruments such as network analyzers, protocol testers, and data acquisition systems benefit from the LAN9355/PT's IEEE 1588v2 hardware timestamping and cable diagnostics. Engineers can synchronize measurements across multiple distributed test stations with sub-microsecond accuracy, critical for power systems testing and high-speed data acquisition. The 3-port configuration supports a test port, reference clock port, and management uplink in a single instrument. TDR-based cable diagnostics identify cable faults during field calibration, while port mirroring enables passive traffic capture for protocol analysis. The device's small 12x12 mm footprint fits within space-constrained handheld test instruments.
추천
추천 제품 요약
엔지니어링 참조 데이터: LAN9355/PT — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | LAN9355I/PT | LAN9252I/PT | LAN9353/PT | LAN9303/PT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 80-TQFP-EP (12x12 mm) | 80-TQFP-EP (12x12 mm) - same | 80-TQFP-EP (12x12 mm) - same | 80-TQFP-EP (12x12 mm) - same | 80-TQFP-EP (12x12 mm) - same |
| Number of Ports | 3 | 3 | 2 | 3 | 3 |
| Data Rate | 10/100 Mbps | 10/100 Mbps | 10/100 Mbps | 10/100 Mbps | 10/100 Mbps |
| IEEE 1588 Timestamping | Yes | Yes | Yes | No | No |
| Management Features | Full managed (VLAN/QoS/IGMP) | Full managed | EtherCAT slave | Reduced management | Unmanaged |
| Operating Temperature | 0 C to +70 C | -40 C to +85 C | -40 C to +85 C | 0 C to +70 C | 0 C to +70 C |
| Supply Voltage | 1.8-3.3 V | 1.8-3.3 V | 3.3 V | 1.8-3.3 V | 1.8-3.3 V |
| Unit Price (qty 100, as of 2026-10-22) | $5.95 | $7.85 | $8.40 | $5.10 | $4.20 |
주요 차별점
- Industrial temperature drop-in variant with same footprint (vs LAN9355I/PT)
- Integrated 3 PHYs eliminate external components (vs LAN9252I/PT)
- Full IEEE 1588v2 hardware timestamping (vs LAN9303/PT)
설계 노트
The LAN9355/PT integrates 3 high-speed 100BASE-TX PHYs, each requiring careful PCB layout. Use a 4-layer FR4 stackup with continuous ground plane beneath the device. Ethernet differential pairs require 100-ohm differential impedance with intra-pair length matching better than 50 mil. Place the 49.9-ohm 1% termination resistors within 5 mm of the PHY TX/RX pins. The exposed thermal pad must be soldered to a 5x5 mm minimum copper pour with thermal vias (0.3 mm pitch) to the inner ground plane for heat dissipation, especially in sealed enclosures without airflow.
Decoupling the LAN9355/PT requires multiple capacitor values at each supply pin. Place a 0.1 uF X7R ceramic within 2 mm of every VDD pin, plus a 10 uF bulk capacitor at the 3.3V analog supply and 1.8V digital core. Power sequencing is not required since the device handles power-on-reset internally, but ensure analog and digital supplies rise within 100 ms of each other. Estimated worst-case power consumption: 3 ports active at 100 Mbps = 750 mW; energy-detect sleep mode drops to 120 mW per datasheet typical values.
Do not omit the 25 MHz reference clock accuracy check - the LAN9355/PT requires +/- 50 ppm stability for IEEE 1588 timestamp accuracy. A common mistake is using the internal PHY clock as the system reference, which couples Ethernet traffic jitter into the host processor timing. Use a separate low-jitter crystal or TCXO for industrial applications requiring PTP grandmaster functionality. Also verify that the magnetics module selected is rated for the device's 3.3V center-tap voltage, not 2.5V, as mismatch causes link instability and increased EMI.
The 80-TQFP-EP package dissipates approximately 750 mW with all 3 ports at 100 Mbps full-duplex. Theta_JA is 28 C/W on a 4-layer JEDEC test board. Estimated junction temperature rise at 25 C ambient: 21 C above ambient, well within the 125 C maximum. However, in sealed IP65 enclosures at 60 C ambient, the junction temperature approaches 95 C, leaving limited margin. Either add airflow, downclock to one active port, or upgrade to the LAN9355I/PT with industrial temperature rating for hot environments.
규정 준수 정보
RoHS compliant per Microchip product page. Not AEC-Q100 qualified (automotive) - choose AEC-Q100 qualified part for automotive applications. Commercial temperature grade only on LAN9355/PT; industrial grade LAN9355I/PT available for -40 to +85 C.
