Ethernet PHY chips

1.Core functions of Ethernet PHY chips

Ethernet PHY (Physical Layer) chips are the underlying hardware core of data communication, responsible for converting digital signals into analog signals on physical media (such as cables or optical fibers) and achieving reliable connections between devices. Its core functions include:

• Signal modulation and coding
• Modulation technology: converting digital signals of the MAC layer (such as MII, GMII interfaces) into differential signals suitable for transmission (such as MLT-3, PAM4 coding).
• Coding scheme: 例如, Manchester coding for 10BASE-T, 4B5B coding for 100BASE-TX, and 8B10B coding for Gigabit Ethernet to ensure signal synchronization and anti-interference.
• Adaptation and link negotiation
• Auto-Negotiation: automatically matching the speed (10M/100M/1G/10G) and duplex mode (full-duplex/half-duplex) of the peer device.
• Link training: dynamically adjusting equalization parameters in high-speed Ethernet (such as 10GBASE-T) to compensate for channel loss.
• Electrical isolation and anti-interference
• Transformer coupling: Block DC components through magnetic isolation to protect equipment from ground loops and surges.
• EMI suppression: Built-in filtering circuit to reduce interference of high-frequency radiation on sensitive circuits.
• Power management
• Energy-Efficient Ethernet (EEE, 802.3az): Reduce power consumption when idle, suitable for IoT and portable devices.

2.Integrated and customized PHY products
To meet the needs of different scenarios, manufacturers provide highly integrated or customized Ethernet PHY solutions:

• Single-chip integration solution
• PHY+MAC integration: such as Microchip’s LAN867x series, built-in MAC and PHY, simplifying design complexity.
• Multi-port PHY: Supports 4-8-port switch PHY chips (such as Marvell 88E6390) for industrial gateways and routers.
• Industrial-grade customized PHY
• Wide temperature support: -40°C to +125°C operating range (such as TI DP83822), adapting to harsh industrial environments.
• Enhanced EMC performance: Passed IEC 61000-4 industrial anti-interference certification (such as ADI ADIN1300).
• Automotive Ethernet PHY
• AEC-Q100 certification: Meet vehicle reliability requirements (such as NXP TJA1100).
• Single twisted pair (100BASE-T1/1000BASE-T1): Saves wiring harness weight and supports ADAS and in-vehicle entertainment systems.
• High-speed PHY chip
• Multi-rate support: 10G/25G/40G/100G (such as Broadcom BCM8488 series), used in data centers and 5G base stations.
• Optical module integration: SFP+/QSFP28 PHY supports direct fiber connection (such as Intel 800 series).

3. Ethernet PHY market landscape
The Ethernet PHY chip market is growing rapidly. The global market size will be approximately US$3 billion in 2023 and is expected to exceed US$6 billion in 2028 (CAGR 12%). Key drivers include:

• Competition among major manufacturers
• Traditional giants: Broadcom, Marvell, Texas Instruments (TI), Realtek.
• Emerging players: Microchip, NXP, Silicon Labs.
• Market growth points
• 5G and edge computing: 5G base stations and edge servers drive the demand for 10G/25G PHY.
• Industry 4.0: Industrial Ethernet (EtherCAT, Profinet) penetration rate increases.
• Automotive intelligence: The number of Ethernet ports per vehicle increases from 10+ 到 100+ (L4 autonomous driving).
• AI and data centers: 100G/400G optical module PHY supports AI training clusters.
• Technology trends
• Low-power design: NBASE-T (2.5G/5G) PHY chips for IoT.
• Multi-protocol compatibility: Supports PoE (802.3bt) power supply and data transmission integration.

4.Application fields of Ethernet PHY

• Industrial automation
• Industrial Ethernet protocol: underlying physical layer implementation of EtherCAT, Profinet, and Powerlink.
• Scenarios: PLC control, machine vision, and remote IO modules.
• Automotive electronics
• In-vehicle network: smart cockpit (4K video transmission), autonomous driving domain controller (1000BASE-T1).
• Diagnosis and OTA: remote firmware upgrade via DoIP (Diagnostics over IP).
• Data center and cloud computing
• High-speed interconnection: 100G/400G optical module PHY is used for server and switch interconnection.
• SmartNIC: PHY chip with integrated RDMA and TCP/IP offload.
• Consumer electronics
• Smart home: 2.5G Ethernet backhaul for Wi-Fi 6 路由器.
• Gaming equipment: low-latency Gigabit PHY (such as the 2.5G network port of Xbox Series X).
• Energy and Infrastructure
• Smart Grid: Hybrid Networking of Power Line Communication (PLC) and Ethernet.
• Smart City: Gigabit Connection between IP Cameras and Edge Servers.

5 .Future Challenges and Opportunities

• Challenges:
• Difficulty of PCB design for high-speed signal integrity (56G PAM4 and above).
• Functional safety (国际标准化组织 26262) certification cost of automotive-grade PHY.
• Opportunities:
• Silicon photonic integration: Integrate lasers with PHY chips to reduce the cost of optical modules.
• TSN (Time Sensitive Network): Industrial PHY chips that support deterministic delays.

Conclusion
As the “physical bridge” of the digital world, Ethernet PHY chips are developing from general-purpose to highly customized, driven by technology iteration and market demand. Whether it is reliable communication in industrial sites, real-time guarantee of intelligent driving of automobiles, or high-speed interconnection of data centers, the innovation of PHY chips will continue to enable the intelligent future of the Internet of Everything.