LAN8740AI-EN - 10/100 Ethernet PHY, RMII/MII, 32-SQFN | Microchip
部品番号: LAN8740AI-EN ✓ 生産中LAN8740AI-EN 概要
An Ethernet PHY is the physical-layer transceiver that converts parallel digital data from a MAC into differential 10BASE-T or 100BASE-TX signalling on a twisted-pair cable, and converts the incoming analogue signal back into digital words. In the OSI hierarchy a PHY sits below the MAC inside the data-link layer, and the device therefore belongs to the network interface controller family of integrated circuits alongside MAC controllers and USB-to-Ethernet bridges.
Key features include auto-negotiation for automatic speed and duplex selection, HP Auto-MDIX for direct-connect or crossover cable use without manual crossover wiring, auto-polarity correction, deterministic loopback delay for real-time system performance, and cable diagnostics that reduce installation and service cost. The device is compliant with IEEE 802.3 and IEEE 802.3u and is well suited to consumer, embedded and industrial equipment.
The LAN8740Ai also carries Microchip's flexPWR technology, an integrated low-power design approach that removes the need for an external switching regulator for the PHY core. This reduces board area, component count and overall system power, which is decisive in battery-backed and Energy Efficient Ethernet designs where the PHY is frequently the largest standby consumer on the board.
Typical uses include industrial Ethernet gateways, PLC and HMI panels, IP cameras and NVRs, set-top boxes and consumer set-top equipment, printer and copier controllers, embedded Linux boards using an RMII-capable SoC, and network-connected sensors and IoT nodes. The small 5x5 mm footprint keeps the PHY compact enough for space-constrained embedded boards while the 32-pin SQFN keeps the pin count manageable for four-layer PCB design.
The main design trade-off is interface choice: RMII reduces the host pin count to a minimum and therefore lowers EMI and cost, but it is sensitive to clock timing and requires a stable 50 MHz reference, whereas full MII offers a parallel, more forgiving bus at the expense of roughly thirty signal pins. Commercial designs should confirm RMII clock, reference and crystal/oscillator requirements against the manufacturer datasheet before layout is frozen.
This page consolidates the manufacturer device documentation, verified distributor listings, drop-in alternatives and practical PCB and layout guidance into a single design reference, so that schematic and layout decisions for a LAN8740Ai-based Ethernet port can be made without assembling the same information from many sources.
ドロップイン代替品: LAN8740AI-EN — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: LAN8740AI-EN （同一形状・フットプリント） — 相違点: Auto-Negotiation, Package, Auto-MDIX, Product Type, Commercial Temperature Range.
LAN8740A-EN
✅ ドロップイン価格はお問い合わせください
データシートを見る →LAN8740AI-EN-TR
✅ ドロップイン📋 参考代替品（カタログ未掲載）
LAN8741AI-EN
✅ ドロップイン価格はお問い合わせください
データシートを見る →LAN8742A-EN
✅ ドロップイン ⚠️ 仕様未検証📋 参考代替品（カタログ未掲載）
LAN8740A-EN-TR
✅ ドロップイン📋 参考代替品（カタログ未掲載）
LAN8740AI-EN 仕様
| Device Type | 10/100 Ethernet PHY transceiver (1 port) |
| データレート | 10 Mbps / 100 Mbps |
| Host Interface | MII and RMII |
| Standards Compliance | IEEE 802.3, IEEE 802.3u |
| パッケージ | 32-SQFN (5 x 5 mm) |
| ピン数 | 32 pins |
| 実装タイプ | Surface mount |
| Temperature Range (AI grade) | -40 °C to +85 °C (industrial) |
| Auto-Negotiation | Supported (automatic speed and duplex selection) |
| Auto-MDIX | HP Auto-MDIX supported (direct or crossover cable) |
| Auto-Polarity Correction | Supported |
| Loopback | Deterministic loopback delay for real-time performance |
| Cable Diagnostics | Supported, reduces network installation cost |
| Low Power Technology | flexPWR integrated low-power design |
| Operating Temperature (commercial LAN8740A) | 0 °C to +70 °C |
| AEC-Q100 Qualification | not_applicable |
LAN8740AI-EN 32-sqfn (5 x 5 mm) ピン配置ガイド
LAN8740AI-EN (32-sqfn (5 x 5 mm) パッケージ) のピン配置。 ピン番号、機能、接続図はメーカーのデータシートで定義されています。正確なフットプリントとはんだ付けのガイドラインについては、データシートを参照してください。
詳細なピン配置データはありません: LAN8740AI-EN.
詳細は データシート をご参照ください。
主な用途
LAN8740AI-EN の用途: 6 件s: Industrial Ethernet Gateway and PLC, IP Camera and Video Surveillance, Embedded Linux and IoT Boards, Consumer Network Equipment and Set-Top Boxes, Industrial Sensor and Measurement Networks, Power and Networking Test Equipment.
Industrial Ethernet Gateway and PLC
The LAN8740AI-EN fits industrial gateways, PLCs and HMI panels that must run unattended across a -40 °C to +85 °C ambient range. Its 10/100 Base-T interface with auto-negotiation, HP Auto-MDIX and auto-polarity correction removes site commissioning steps because link speed, duplex and cable polarity are resolved automatically by the PHY rather than by firmware configuration. The integrated flexPWR low-power approach eliminates the external switching regulator normally needed for the PHY core, which shrinks the board and reduces conducted emissions that matter in Class A industrial installations. Combined with deterministic loopback delay and cable diagnostics, it supports both real-time control traffic and field service diagnostics. The 32-SQFN 5 x 5 mm footprint fits easily into the space-constrained baseplates typical of DIN-rail mounted equipment.
おすすめ
IP Camera and Video Surveillance
Network cameras and NVRs place a hard limit on board area and standby power, and the LAN8740AI-EN addresses both with a 32-SQFN 5 x 5 mm footprint and the flexPWR integrated low-power design. Energy Efficient Ethernet behaviour means the PHY can be placed into a low-power state when the link is idle, which directly reduces the overall standby current of a camera that idles most of the day. Because the device supports both RMII and MII, it can pair with a low-cost RMII-capable application processor for cost-sensitive consumer cameras or with an FPGA-based pipeline for multi-stream encoding designs. The industrial temperature rating of the AI grade allows the same device to serve outdoor housings and unheated enclosures where ambient temperatures fall well below the commercial 0 °C limit.
おすすめ
Embedded Linux and IoT Boards
Embedded Linux single-board computers and IoT gateways frequently use a dedicated PHY beside the host SoC rather than integrating Ethernet in the application processor. The LAN8740AI-EN is a natural fit here because the RMII interface keeps the host-side connection to a handful of signals, reducing both PCB routing effort and EMI exposure compared with a full MII bus. The 50 MHz reference clock requirement of RMII must be planned with the SoC clock tree during schematic capture, and the LAN8740Ai datasheet should be used to confirm the exact clock, supply and decoupling requirements. The flexPWR low-power architecture is valuable in battery-backed nodes where the idle network interface is often the dominant standby load, and the industrial temperature grade supports deployments in unheated cabinets and outdoor sensor gateways.
おすすめ
Consumer Network Equipment and Set-Top Boxes
Set-top boxes, printers, copiers and home gateways need a reliable 10/100 port in a small, cost-driven enclosure. The LAN8740AI-EN provides that port in a 32-SQFN footprint with auto-negotiation and HP Auto-MDIX, so users can connect either a straight-through or crossover lead without configuration. For designs in this class that are guaranteed to stay inside a room-temperature enclosure, the commercial LAN8740A-EN offers the same silicon and pinout at a lower temperature grade, which is a sensible cost reduction. Care should be taken that the supply rails and the crystal or oscillator population are checked against the manufacturer datasheet before the schematic is frozen, since those details determine whether the device starts up reliably across all production units.
おすすめ
Industrial Sensor and Measurement Networks
Field-mounted sensors, condition-monitoring nodes and data loggers need an Ethernet port that keeps working in vibration, temperature swings and electrically noisy environments. The LAN8740AI-EN industrial rating of -40 °C to +85 °C, together with auto-polarity correction and HP Auto-MDIX, makes it resilient to the inconsistent cabling typical of retrofitted installations. The cable diagnostics function helps commissioning crews identify opens, shorts and length problems remotely, reducing truck rolls and installation cost. Because the PHY is a 10/100 device, it pairs naturally with isolated bus transceivers for the sensor side of the node, while the same board can be fitted into a compact enclosure with a 32-SQFN footprint that leaves room for the magnetics and isolation components.
おすすめ
Power and Networking Test Equipment
Protocol analysers, network test appliances and industrial diagnostic consoles benefit from a PHY with deterministic loopback delay, because repeatable timing is what makes measurement results trustworthy. The LAN8740AI-EN provides this loopback behaviour along with cable diagnostics, allowing a single device to verify link quality as well as carry traffic. The RMII interface keeps the host-side bus short, which reduces the crosstalk that would otherwise degrade accuracy in a densely populated analyser chassis. In laboratory and field service equipment that may be operated in uncontrolled environments, the industrial temperature grade of the AI variant is appropriate, while the option to select the commercial LAN8740A-EN for temperature-controlled indoor instruments can reduce cost with no functional penalty.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: LAN8740AI-EN — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | LAN8740A-EN | LAN8740AI-EN-TR | LAN8741AI-EN | LAN8742A-EN | LAN8740A-EN-TR |
|---|---|---|---|---|---|---|
| Package | 32-SQFN (5x5 mm) | 32-SQFN (5x5 mm) - same | 32-SQFN (5x5 mm) - same | 32-SQFN (5x5 mm) - same | 32-SQFN (5x5 mm) - same | 32-SQFN (5x5 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Temperature Range | -40 °C to +85 °C (industrial) | 0 °C to +70 °C (commercial) | -40 °C to +85 °C (industrial) | -40 °C to +85 °C (industrial) | -40 °C to +85 °C (industrial) | 0 °C to +70 °C (commercial) |
| Data Rate | 10/100 Base-T | 10/100 Base-T | 10/100 Base-T | 10/100 Base-T | 10/100 Base-T | 10/100 Base-T |
| Host Interface | MII and RMII | MII and RMII | MII and RMII | MII and RMII | MII and RMII | MII and RMII |
| Auto-MDIX / Auto-Negotiation | HP Auto-MDIX and auto-negotiation supported | HP Auto-MDIX and auto-negotiation supported | HP Auto-MDIX and auto-negotiation supported | HP Auto-MDIX and auto-negotiation supported | HP Auto-MDIX and auto-negotiation supported | HP Auto-MDIX and auto-negotiation supported |
| Standards Compliance | IEEE 802.3, IEEE 802.3u | IEEE 802.3, IEEE 802.3u | IEEE 802.3, IEEE 802.3u | IEEE 802.3, IEEE 802.3u | IEEE 802.3, IEEE 802.3u | IEEE 802.3, IEEE 802.3u |
主な差別化要因
- Industrial temperature coverage in a small 32-SQFN footprint （vs LAN8740A-EN)
- Integrated flexPWR low-power design removes a supply block （vs LAN8741AI-EN)
- Single-part family coverage of common link features （vs LAN8742A-EN)
- Deterministic loopback and cable diagnostics for serviceable networks （vs KSZ8041RNL)
設計ノート
Keep the RMII host-side traces short and matched on length, and place the PHY close to the RJ-45 magnetics rather than at the far edge of the board. RMII timing margins are set by the 50 MHz reference clock, so route TXD, TX_EN, RXD and CRS_DV as a compact group away from switching nodes and noisy clocks. Use the package drawing and recommended land pattern in the manufacturer datasheet for the 32-SQFN footprint, including the exposed thermal pad tied to ground, and confirm the pad-to-pour clearance for your assembly house's solder mask definition.
The flexPWR architecture of the LAN8740Ai removes the external switching regulator for the PHY core, but the core and I/O rails still need clean local decoupling. Follow the manufacturer datasheet recommendation for input and output bulk and high-frequency capacitors and place them directly at the supply pins with a short ground return via the exposed pad region. Estimate the rail budget before schematic sign-off: total dissipation is approximately VIN minus VOUT multiplied by the PHY current, and adding that figure to the ambient in a sealed enclosure gives the junction temperature the design must tolerate.
Ethernet ports are a common source of compliance problems because the differential pairs couple directly to cable-borne emissions. Terminate the 100BASE-TX and 10BASE-T pairs with the magnetics' recommended network-side network and follow the split termination recommended by the transformer supplier. Keep the copper pour below the magnetics minimal where the datasheet calls for it, and provide a clean, unbroken ground plane from the PHY exposed pad to the RJ-45 chassis ground. Where the design must pass industrial EMC limits, verify the enclosure bonding and consider a common-mode choke in the magnetics path.
Two mistakes cause most field failures with this class of device. First, choosing the commercial LAN8740A-EN for equipment that can see temperatures below 0 °C or above 70 °C; the AI grade is the industrial option and the difference is a guaranteed operating range, not a price label. Second, assuming auto-negotiation and HP Auto-MDIX remove the need for a proper 50 MHz reference clock and correct crystal selection on the RMII side; confirm clock source, tolerance and startup time against the manufacturer datasheet, and confirm the cable diagnostics behaviour before relying on it for remote fault finding.
コンプライアンス情報
The device is compliant with IEEE 802.3 and IEEE 802.3u. RoHS, REACH, lead-free and halogen-free statements are not stated in the product listings for this part and must be confirmed on the manufacturer product page or the material declaration for the specific ordering code.
