HN4263VG HN4264VG 10/100Base-T LAN Transformer Overview

Applications

10/100Base-T SMT LAN Transformers are widely used in Ethernet-based systems to provide signal isolation, EMI suppression, and impedance matching between the PHY and the RJ45 connector. Their compact SMT (Surface-Mount Technology) design allows for high-density PCB assembly and reliable performance in networking equipment.

Typical Applications include:

• LAN Switches and Hubs – Ensure stable data transmission across multiple ports.
• Routers, Gateways, and Access Points – Provide electrical isolation and noise suppression for home and enterprise networks.
• Industrial Ethernet Devices – PLCs, controllers, and monitoring systems requiring robust performance in harsh environments.
• Network Interface Cards (NICs) – Used in PCs, servers, and embedded systems for reliable Ethernet connectivity.
• VoIP Phones & IP Cameras – Support PoE and stable Ethernet transmission for voice and video devices.
• Smart IoT Devices – Gateways, sensors, and automation systems requiring 10/100 Mbps connectivity.

FAQ – 10/100Base-T SMT LAN Transformer

1. What is the function of a 10/100Base-T SMT LAN Transformer?
It provides galvanic isolation between the Ethernet PHY and cable, suppresses EMI, matches impedance, and ensures compliance with IEEE 802.3 Ethernet standards.

2. Why use SMT LAN Transformers instead of through-hole types?

• Smaller footprint, ideal for high-density PCB layouts
• Automated pick-and-place assembly for cost efficiency
• Lower profile for compact designs

3. Can a 10/100Base-T LAN transformer be used for Gigabit Ethernet?
No. A 10/100Base-T transformer is optimized for Fast Ethernet (10/100 Mbps). For Gigabit Ethernet (1000Base-T), a transformer with wider bandwidth and additional windings is required.

4. Do SMT LAN Transformers support PoE (Power over Ethernet)?
Yes, many SMT LAN transformers are designed with PoE (IEEE 802.3af/at) capability, enabling them to safely transmit both data and power over the same Ethernet cable.

5. What are the key parameters when selecting a LAN transformer?

• Turns ratio (TX/RX winding ratio)
• OCL (Open Circuit Inductance)
• Insertion loss, return loss, crosstalk, and CMR performance
• PoE power level support (15W, 30W, 60W, etc.)
• Hi-pot isolation voltage
• Operating temperature range
• Compliance with RoHS, IEEE 802.3

6. Are 10/100Base-T SMT LAN transformers backward compatible with legacy Ethernet?
Yes. They support both 10 Mbps and 100 Mbps Ethernet, ensuring compatibility with older devices.

7. What are the benefits of integrated SMT LAN Transformers in design?

• Reduced component count (transformer + chokes in one package)
• Improved reliability due to shorter signal paths
• Better EMI suppression for stable system performance
• Optimized PCB space usage for compact designs