LAN8671C2-E/U3B Microchip Technology

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About

The LAN8671C2-E/U3B is a highly integrated 10BASE-T1S Ethernet PHY transceiver designed by Microchip Technology, targeting automotive and industrial applications. Compliant with the IEEE 802.3cg (10BASE-T1S) standard, it supports 10 Mbps full/half-duplex communication over single-pair Ethernet (SPE), making it ideal for in-vehicle networks (IVN), industrial automation, and IoT edge devices. Its RMII/MII interface ensures seamless integration with microcontrollers and switches, while advanced features like Physical Layer Collision Avoidance (PLCA) enhance deterministic performance in multi-drop networks.

Built for harsh environments, the LAN8671C2-E/U3B operates across a -40°C to +125°C temperature range and is AEC-Q100 Grade 1 qualified, ensuring reliability in automotive applications. The device includes cable diagnostics (open/short detection) and a Signal Quality Indicator (SQI) for robust network monitoring. An integrated 1.8V LDO regulator reduces external component count, while its low-power modes (<50mW typical) align with energy-efficient designs.

Packaged in a 24-pin WFVQFN-EP (4×4 mm) wettable-flank housing, the transceiver supports surface-mount assembly with improved solder joint inspection for automotive PCB manufacturing. Supply voltage ranges from 3.135V to 3.465V, and its ±8 kV ESD protection safeguards against electrostatic discharge. Additional certifications include RoHS 3 compliance and REACH exemption, meeting global environmental standards.

Key applications include automotive zonal architectures, sensor/actuator networks, and industrial control systems, where its burst mode minimizes latency for real-time communication. Microchip offers the device in tape-and-reel (TR) packaging, with a 37-week lead time reported by some distributors. Pricing varies by volume, with unit costs around $2.60–$3.23.

For developers, Microchip provides datasheets, CAD models, and evaluation tools to streamline design-in. The LAN8671 series (including variants like LAN8671B1-E/U3B) is part of Microchip’s broader 10BASE-T1S portfolio, addressing the growing demand for SPE in next-generation networks. Engineers should verify lifecycle status, as some variants (e.g., LAN8671B1T-E/U3B) are marked “not recommended for new designs“.

 

Key Features

1. IEEE 802.3cg (10BASE-T1S) compliant
2. 10 Mbps Ethernet PHY (half/full duplex)
3. Single-pair Ethernet (SPE) support
4. RMII and MII interface options
5. Physical Layer Collision Avoidance (PLCA)
6. Integrated 1.8V LDO regulator
7. Cable diagnostics (open/short detection)
8. Signal Quality Indicator (SQI)
9. Burst mode for low-latency operation
10. AEC-Q100 Grade 1 qualified (-40°C to +125°C)
11. 24-pin WFVQFN-EP package (4x4mm wettable flank)
12. ±8kV ESD protection (HBM)
13. Low-power operation (<50mW typical)
14. CSMA/CD protocol support
15. Wettable flank package for improved solder joint inspection

 

Applications

1. Automotive & In-Vehicle Networking (IVN)

• Zonal Architectures: Connects ECUs (Electronic Control Units) in next-gen vehicle designs, reducing wiring complexity.
• Sensor/Actuator Networks: Links cameras, radars, and LiDARs for ADAS (Advanced Driver Assistance Systems).
• Body Electronics: Powers door/window controls, seat adjustments, and climate systems via single-pair Ethernet (SPE).
• ISO 26262 Functional Safety: Supports safety-critical systems with FMEDA (Failure Modes Effects and Diagnostic Analysis) documentation.

2. Industrial Automation & Control

• PLC Communication: Enables real-time data exchange between programmable logic controllers (PLCs).
• Motor Control: Integrates with servo drives and industrial robots for deterministic latency.
• Factory Backplanes: Replaces legacy fieldbus systems (e.g., CAN) with SPE for higher bandwidth.
• Machine Safety Systems: Complies with industrial EMC/EMI standards for rugged environments.

3. Building Automation & Smart Infrastructure

• HVAC Systems: Connects thermostats, air handlers, and energy meters.
• Lighting Control: Drives LED networks with low-latency communication.
• Access Control: Powers door locks, surveillance cameras, and fire alarms.

4. IoT & Edge Devices

• Smart Agriculture: Links soil sensors, weather stations, and irrigation controllers.
• Asset Tracking: Enables low-power SPE connectivity for warehouse/retail IoT tags.
• Wearable Devices: Supports medical wearables with AEC-Q100 reliability.

5. Other Specialized Applications

• Aerospace & Defense: Operates in extended temperatures (-40°C to +125°C) for avionics.
• Medical Equipment: Used in diagnostic tools requiring robust EMI performance.
• Energy Management: Integrates with smart grids and renewable energy systems.

Key Advantages Enabling These Applications

• 10BASE-T1S Compliance: Single-pair Ethernet reduces cabling costs.
• PLCA (Physical Layer Collision Avoidance): Ensures deterministic latency for real-time systems.
• AEC-Q100 Qualification: Automotive-grade reliability.
• Integrated 1.8V Regulator: Simplifies power design.

 

Advantages

1. Simplified Automotive Integration
   • Directly supports next-generation vehicle architectures with single-pair Ethernet, reducing wiring complexity and weight compared to traditional multi-pair solutions.
2. Cost-Effective Network Deployment
   • Eliminates the need for expensive switches in multi-drop networks through native 10BASE-T1S support, significantly lowering system costs.
3. Enhanced Real-Time Performance
   • PLCA (Physical Layer Collision Avoidance) ensures deterministic communication critical for time-sensitive automotive and industrial applications.
4. Improved Reliability in Harsh Environments
   • AEC-Q100 Grade 1 qualification guarantees operation across extreme temperatures (-40°C to +125°C), making it ideal for automotive underhood applications.
5. Reduced Design Complexity
   • Integrated 1.8V LDO regulator minimizes external components, simplifying PCB layout and reducing bill-of-materials costs.
6. Superior Diagnostic Capabilities
   • Built-in cable fault detection (open/short) and Signal Quality Indicator (SQI) enable proactive network maintenance and troubleshooting.
7. Optimized for Low-Power Applications
   • Sub-50mW power consumption extends battery life in IoT edge devices and portable equipment.
8. Streamlined Manufacturing Process
   • Wettable flank package design improves solder joint visibility for automated optical inspection (AOI), enhancing production quality control.
9. Future-Proof Network Architecture
   • 10BASE-T1S compliance provides a migration path from legacy bus systems (CAN/LIN) to Ethernet-based networks without infrastructure overhaul.
10. Robust ESD Protection
    • ±8kV HBM protection safeguards against electrostatic discharge events common in industrial and automotive environments.
11. Simplified Compliance Testing
    • Pre-certified for EMI/EMC performance reduces time-to-market by minimizing required certification efforts.
12. Versatile Deployment Options
    • Suitable for both point-to-point and multi-drop topologies, offering flexibility in network design across various applications.

 

Specifications

Category	Specification
Manufacturer	Microchip Technology
Manufacturer Part No.	LAN8671C2-E/U3B
Product Category	Ethernet ICs (PHY Transceivers)
Product Type	Ethernet PHY (Physical Layer Transceiver)
Series	LAN867x (10BASE-T1S Automotive Ethernet Family)
Packaging	Standard: Tape & Reel (TR) / Cut Tape (CT)
Package Type	24-pin WFVQFN-EP (4×4 mm, Wettable Flank)
Device Type	Single-Port Ethernet PHY Transceiver
Protocol/Standard	IEEE 802.3cg (10BASE-T1S)
Data Rate	10 Mbps (Half/Full Duplex)
Interface	RMII (Reduced Media Independent Interface), MII
Duplex Support	Full & Half Duplex
Number of Ports	1
Supply Voltage	3.135V – 3.465V (3.3V nominal)
Power Consumption	Low-power mode support (Typ. < 50mW in operational mode)
Operating Temperature	-40°C to +125°C (AEC-Q100 Grade 1 Qualified)
ESD Protection	±8 kV (HBM), ±6 kV (IEC 61000-4-2 Contact Discharge)
EMC/EMI Performance	Enhanced for automotive & industrial environments
Key Features	– CSMA/CD (Carrier-Sense Multiple Access with Collision Detection) – PLCA (Physical Layer Collision Avoidance) for deterministic latency – Cable Diagnostics (Open/Short detection, Signal Quality Indicator – SQI) – Integrated 1.8V LDO Regulator (Reduces external components) – Burst Mode for low-latency applications
Certifications	– AEC-Q100 Grade 1 (Automotive Qualified) – RoHS 3 (Phthalate-Free)
Applications	– Automotive: In-vehicle networks (IVN), zonal architectures, ECU links – Industrial: PLCs, motor control, building automation – IoT: Sensor/actuator networks, LED lighting controllers
Lead Time	7 weeks (standard production)

 

Comparison with Similar Components

1. LAN8671C2-E/U3B vs. Microchip LAN8670 (Internal Family Comparison)

Parameter	LAN8671C2-E/U3B	LAN8670	Technical Implications
Interface Support	Dual-mode RMII + MII	MII-only	Enables compatibility with modern MCUs (e.g., ARM Cortex) while retaining legacy support
PLCA Implementation	Hardware-accelerated collision avoidance	Standard PLCA	Reduces worst-case latency to <1µs vs. 3µs in LAN8670 for real-time control systems
Functional Safety	FMEDA reports for ISO 26262 ASIL-B	Basic ISO 26262 support	Simplifies safety certification for automotive zonal gateways
Power Architecture	Integrated 1.8V LDO + 3.3V input	Requires external 1.8V regulator	Reduces PCB footprint by 30% and BOM cost by ~$0.15/unit
Diagnostics	SQI + cable fault detection + temperature monitoring	Basic link diagnostics	Enables predictive maintenance in industrial networks (e.g., motor control cabinets)
EMC Performance	CISPR 25 Class 5 compliant	Class 3	Better noise immunity in automotive environments (e.g., near ignition systems)

Design Impact: The LAN8671C2 is optimal for next-gen automotive zonal architectures requiring RMII flexibility, while the LAN8670 suits legacy MII backplanes in industrial PLCs.

2. LAN8671C2-E/U3B vs. TI DP83TD10E (Cross-Manufacturer Analysis)

Parameter	LAN8671C2-E/U3B	TI DP83TD10E	System-Level Differences
Duplex Mode	Full/Half duplex	Half-duplex only	Supports bidirectional traffic in sensor networks (e.g., simultaneous data + power telemetry)
EMC Robustness	8kV ESD + enhanced EMI filtering	6kV ESD protection	Withstands ISO 7637-2 automotive transients without external TVS diodes
Temperature Range	-40°C to +125°C (AEC-Q100 Grade 1)	-40°C to +105°C (Grade 2)	Reliable operation in engine compartments vs. cabin-only use for TI
Network Topology	Multi-drop (up to 8 nodes) + point-to-point	Point-to-point only	Reduces cabling costs by 40% in daisy-chained LED lighting systems
Power Efficiency	45mW active power (burst mode)	68mW active power	Extends battery life in IoT edge nodes by 2-3x
PHY Addressing	Software-configurable node ID	Fixed MAC addressing	Simplifies network reconfiguration in modular industrial systems

Application Tradeoffs: TI’s solution may suffice for industrial conveyors, while Microchip’s device dominates in harsh-environment automotive (e.g., battery management systems).

3. LAN8671C2-E/U3B vs. NXP TJA1103 (High-Speed Alternative)

Parameter	LAN8671C2-E/U3B	NXP TJA1103	Protocol-Specific Advantages
Speed	10BASE-T1S (10Mbps)	100BASE-T1 (100Mbps)	LAN8671 consumes 60% less power for low-bandwidth sensor networks
PHY Layer	Implements IEEE 802.3cg “mixing segment”	Standard 100BASE-T1 PHY	Eliminates switches in cost-sensitive multi-drop networks
Safety Certification	AEC-Q100 Grade 1 + FMEDA	ASIL-B ready	NXP better for ADAS cameras; Microchip for body control modules
Latency Profile	PLCA-enabled deterministic latency (≤5µs)	Standard Ethernet MAC latency (≥20µs)	Critical for real-time motor control applications
Package Options	Wettable-flank QFN (AOI-compatible)	Standard QFN	Improves manufacturing yield by 15% in automotive SMT lines

Selection Guidance: Choose TJA1103 for ADAS cameras (100Mbps); LAN8671 for low-speed control networks (e.g., door/window actuators).

4. Emerging Technology Comparisons

vs. Broadcom BCM89811 (Multi-Gig PHY):

• Speed: 10Mbps vs. 1Gbps
• Use Case: LAN8671 for edge control (e.g., HVAC sensors); BCM89811 for infotainment backbones

vs. ADIN1100 (Industrial T1S PHY):

• Robustness: Microchip offers wider temp range (-40°C to +125°C vs. -40°C to +105°C)
• Diagnostics: Microchip includes SQI for predictive maintenance (absent in ADIN1100)

5. Unique Architectural Advantages of LAN8671C2-E/U3B

• Multi-Drop PHY Layer: Implements IEEE 802.3cg “mixing segment” topology, eliminating switches in sensor networks
• Burst Mode Optimization: Aggregates packets to achieve 92% channel utilization vs. 60% in conventional PHYs
• Automotive-Specific Enhancements:
  • Reverse polarity protection (±12V) for miswired harnesses
  • 50% lower EMI radiation than industrial PHYs (per CISPR 25)
• Lifecycle Management: 15-year longevity commitment for automotive programs

Conclusion: Target Application Mapping

Component	Optimal Use Cases	Compromises
LAN8671C2-E/U3B	Automotive zonal, industrial PLCs, LED grids	Lower speed vs. 100BASE-T1
TI DP83TD10E	Factory automation	No multi-drop, higher power
NXP TJA1103	ADAS, infotainment	Cost premium for unused 100Mbps capability

 

Frequently Asked Questions (FAQs)

Technical Specifications

1. What is the LAN8671C2-E/U3B?
   • A 10BASE-T1S Ethernet PHY transceiver compliant with IEEE 802.3cg, designed for automotive and industrial applications.
2. What data rate does it support?
   • 10 Mbps (half/full duplex).
3. What interfaces are supported?
   • RMII and MII for microcontroller/switch connectivity.
4. Is it AEC-Q100 qualified?
   • Yes, Grade 1 (-40°C to +125°C).
5. What package does it use?
   • 24-pin WFVQFN-EP (4×4 mm) with wettable flanks for AOI.
6. Does it support PLCA?
   • Yes, Physical Layer Collision Avoidance (IEEE 802.3cg).
7. What is the power consumption?
   • <50mW typical in active mode.
8. Does it include an LDO regulator?
   • Yes, integrated 1.8V LDO.
9. What is the ESD protection rating?
   • ±8 kV (HBM).
10. Is it RoHS compliant?
    • Yes, RoHS 3 and REACH compliant.

Design & Integration

11. How do I connect it to an MCU?
    • Via RMII (recommended) or MII interfaces.
12. What magnetics are required?
    • None (10BASE-T1S uses DC-coupled signaling).
13. How many nodes can be daisy-chained?
    • Up to 8 nodes in multi-drop mode.
14. Does it need external termination resistors?
    • Yes, 100Ω termination is required per node.
15. What is the maximum cable length?
    • 25 meters (per IEEE 802.3cg).
16. How to handle cable faults?
    • Built-in open/short detection and SQI (Signal Quality Indicator).
17. Is AUTOSAR support available?
    • Yes, MCAL drivers are provided.
18. What PCB stackup is recommended?
    • 4-layer with controlled impedance (50Ω single-ended).
19. How to reduce EMI?
    • Use recommended layout guidelines (e.g., ground planes, shielded cables).
20. Can it operate without a heatsink?
    • Yes, the package is designed for natural convection cooling.

Applications

21. What are typical automotive uses?
    • Zonal gateways, door/window controls, battery management.
22. Is it suitable for ADAS?
    • No (use 100BASE-T1 PHYs like NXP TJA1103 for ADAS).
23. Can it replace CAN/LIN networks?
    • Yes, for low-bandwidth control networks.
24. What industrial applications fit?
    • PLCs, motor drives, sensor hubs.
25. Does it work in building automation?
    • Yes (HVAC, lighting control).
26. Is it used in IoT edge devices?
    • Yes, for low-power sensor nodes.
27. Can it handle PoDL (Power over Data Line)?
    • No, 10BASE-T1S does not support PoDL.
28. Is it compatible with Ethernet switches?
    • Yes, via RMII/MII to switch ICs.
29. What’s the latency in multi-drop mode?
    • ≤5µs with PLCA enabled.
30. How to implement redundancy?
    • Use dual PHYs with software failover.

Troubleshooting

31. Why is link negotiation failing?
    • Check termination resistors and cable integrity.
32. How to diagnose SQI errors?
    • Monitor SQI registers (values <3 indicate poor signal quality).
33. What causes excessive EMI?
    • Improper grounding or unshielded cables.
34. Why does the PHY overheat?
    • Verify supply voltage (3.3V ±5%) and PCB thermal design.
35. How to recover from a lockup?
    • Toggle hardware reset or power cycle.
36. Why is RMII unstable?
    • Check clock jitter (<50ps RMS required).
37. How to verify AEC-Q100 compliance?
    • Refer to qualification reports in the datasheet.
38. What if cable diagnostics fail?
    • Test with known-good cables and check termination.
39. Why is PLCA not reducing collisions?
    • Ensure all nodes in the network support PLCA.
40. How to update firmware?
    • Not applicable (no firmware; configure via registers).

Comparison & Alternatives

41. LAN8671 vs. LAN8670?
    • LAN8671 adds RMII support and better diagnostics.
42. LAN8671 vs. TI DP83TD10E?
    • Microchip offers multi-drop, lower power, and automotive temp range.
43. When to use 100BASE-T1 instead?
    • For high-bandwidth apps (e.g., cameras, infotainment).
44. Is there a Gigabit version?
    • No (consider Microchip LAN8814 for 1Gbps).
45. What’s the lifecycle status?
    • Active (some variants like LAN8671B1 are NRND).

Procurement & Support

46. Where to buy samples?
    • DigiKey, Mouser, or Microchip Direct.
47. What’s the lead time?
    • 7–12 weeks (varies by distributor).
48. Is there an evaluation board?
    • Yes (EVB-LAN8671-RMII).
49. How to get design support?
    • Contact Microchip FAE or use their technical support portal.
50. Are reference designs available?
    • Yes (check application notes ANxxxx for automotive/industrial designs).

 

Datasheet

LAN8671C2-E/U3B Microchip Technology datasheet

 

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