原标题：Microchip LAN8770 100BASE－T1以太网PHY收发器解决方案

　　microchip公司的LAN8770是紧凑的成本效益的单端口100BASE-T1以太网PHY层收发器,和IEEE 802.3bw-2015标准兼容.器件在单股非屏蔽双绞线(UTP)电缆上提供100Mbps发送和接收功能,支持电缆长度长达15米. LAN8770可工作在Grade 1汽车温度(-40C 到 +125C),最佳用在AEC-Q100汽油应用如汽车辅助驾驭系统(ADAS),信息娱乐系统,远程信息处理,智能天线和车内主干线. LAN8770支持以太网MAC通过标准MII/RMII/RGMII接口(RGMII仅限于LAN8770R).对于RGMII和RMII应用,可分别提供125MHz 或50MHz基准时钟输出,而集成的SMI接口提供迅速的寄存接入和配置.器件具有3级脉幅调制(PAM-3)线路编码和回声消除功能. EtherGREEN™能量效率如超低功耗睡眠模式(典型12μA)和支持本地叫醒以及睡眠请求识别.主要用在高级驾驶员辅助系统(ADAS), 信息娱乐系统,远程信息处理,智能天线和车内主干线以及网关.本文介绍了LAN8770主要优势和亮点, 系统级框图以及评估板EVB-LAN8770-RMII主要特性,框图,电路图,材料清单和PCB设计图.

　　The Microchip LAN8770 is a compact, cost-effective, single-port 100BASE-T1 Ethernet physical layer transceiver compliant with the IEEE 802.3bw-2015 specification. The device provides 100 Mbit/s transmit and receive capability over a single Unshielded Twisted Pair (UTP) cable, supporting cable lengths of up to at least 15m. The LAN8770 is available in a Grade 1 Automotive (-40C to +125C) temperature range and is optimized for AEC-Q100 automotive use cases such as Automated Driver-Assistance Systems (ADAS), infotainment, telematics, smart antennas, and in-vehicle backbones.

　　The LAN8770 supports communication with an Ethernet MAC via standard MII/RMII/RGMII interfaces (RGMII LAN8770R only). An optional 125MHz or 50MHz reference clock output is provided for RGMII and RMII applications, respectively. Reverse MII mode (LAN8770M only) provides the ability to connect two PHYs back-to-back. An integrated SMI interface provides rapid register access and configuration.

　　Microchips LAN8770 EtherGREEN™ energy efficient technology provides low-power 100BASE-T1 PHY operation along with an ultra low-power sleep mode with local wake-up support (partial networking), sleep request recognition, and various wake/enable signals for low power modes. FlexPWR® variable I/O and core power supply voltages provide

　　flexible design options and power saving opportunities.

　　Advanced PHY diagnostics provide the user with troubleshooting capabilities such as cable defect detection of shorts or opens, a receiver Signal Quality Indicator (SQI), over-temperature, under-voltage protection, comprehensive status interrupt support, and various loopback and test modes.

　　The Microchip LAN8770 family includes the following devices:

　　• LAN8770M

　　• LAN8770R

　　Device specific features that do not pertain to the entire LAN8770 family are called out independently throughout this document.

　　LAN8770主要优势:

　　• High-performance 100BASE-T1 Ethernet PHY

　　- Compliant with IEEE 802.3bw-2015

　　- 100Mbps over single balanced twisted pair cable

　　- OPEN Alliance TC10 sleep/wake-up support

　　- Supports cable lengths up to at least 15m

　　- 3-level Pulse Amplitude Modulation (PAM-3) line coding

　　- Echo cancellation

　　- Jumbo frame support up to 16KB

　　- On-chip termination resistors for balanced UTP cable

　　• MII/RMII/RGMII Interfaces (RGMII LAN8770R only)

　　- 125MHz reference clock output (LAN8770R only)

　　- 25MHz / 50MHz RMII clock mode

　　- Reverse MII mode for back-to-back connection of two PHYs (LAN8770M only)

　　- SMI interface for rapid register access

　　• Low RF Emissions

　　- Integrated transmission filtering

　　- MII/RMII/RGMII drive strength adjust

　　- 125MHz RGMII clock slew rate adjust

　　• EtherGREEN™ Energy Efficiency

　　- Ultra low-power sleep mode (typical 12μA) with local wake-up support (OPEN Alliance TC10)

　　- Sleep request recognition

　　- IDLE detection on MDI

　　- WAKE_IN pulse detection wakeup

　　- INH output for enable/disable of ECU supply

　　- ENABLE dedicated PHY enable/disable input pin

　　• Resets

　　- Pin reset (RESET_N)

　　- Power-On Reset (POR) with brownout protection

　　- Software reset

　　• Packaging

　　- LAN8770M: 32-pin (5 x 5 mm) wettable VQFN

　　- LAN8770R: 36-pin (6 x 6 mm) wettable VQFN

　　• Environmental

　　- AEC-Q100 Grade 1 Automotive temperature range (-40C to +125C)

　　• Functional Safety

　　- FMEDA Computation Spreadsheet (Evaluation of Random Hardware Failures Metric)

　　- Functional Safety Manual

　　LAN8770亮点:

　　• Single-chip Ethernet physical layer transceiver

　　• Compliant with IEEE 802.3bw-2015 (100BASE-T1)

　　• Supports MII/RMII/RGMII (RGMII LAN8770R only)

　　• OPEN Alliance TC10 support / wake-up support

　　• Ultra low power sleep

　　• FlexPWR® technology power management

　　• Advanced Signal Quality Indicator (SQI)

　　• Over-temperature and under-voltage protection

　　• Comprehensive status interrupt support

　　• Extended cable reach

　　• Small footprint 32-pin VQFN (5 x 5 mm) and 36-pin VQFN (6 x 6 mm) with wettable flanks

　　• AEC-Q100 automotive product qualification

　　• Grade 1 Automotive temperature range (-40C to +125C)

　　• Microchip Functional Safety Ready

　　LAN8770目标应用:

　　• Advanced Driver-Assistance Systems (ADAS)

　　• Infotainment

　　• Telematics & Smart Antennas

　　• In-Vehicle Backbone

　　• Gateways

　　图1. LAN8770系统级框图

　　评估板EVB-LAN8770-RMII

　　The EVB-LAN8770-RMII™ Evaluation Board is a plug-in card that interfaces directly

　　with a mating Microchip host processor or controller board, such as the SAMA5D3

　　Ethernet Development System (EDS) Board. It features the LAN8770, a highly integrated

　　networking device that incorporates a 100BASE-T1 physical layer transceiver (PHY). The boards PHY port is connected to a 100BASE-T1 Screw Terminal connector, and the PHYs RMII connections are brought out to a multi-pin connector.

　　Together, the EVB-LAN8770-RMII™ Evaluation Board and the SAMA5D3 EDS Board provide a highly flexible platform for the evaluation of basic PHY features via static Control

　　Status Registers (CSR)。

　　评估板EVB-LAN8770-RMII主要特性:

　　• LAN8770R 100BASE-T1 PHY

　　• TC10 Wake/Sleep capability

　　• Compact EVB design to evaluate 100BASE-T1

　　• Xplained Ultra (latest) RMII connector to interface with Ethernet MCU board including following board-to-board signals:

　　- RMII mode: 50 MHz reference clock from MCU to PHY

　　- MDC/MDIO

　　- PHY Reset

　　- PHY Interrupt

　　- WAKE_IN: Connect to GPIO on MCU

　　- ENABLE: Connect to GPIO on MCU

　　• 3.3V VDD supply and TC10 V battery supply

　　• 2-pin screw terminal connector for 100BASE-T1 physical interface

　　• Single LED indicator for speed/link/activity status

　　图2. 评估板EVB-LAN8770-RMII框图

　　图3. 评估板EVB-LAN8770-RMII带标注的外形图