The Realtek RTL8251CA is a single-chip Fast Ethernet PHY transceiver. It is designed to interface with Fast Ethernet MAC controllers via a standard Media Independent Interface (MII). It provides a physical layer interface for 100BASE-TX and 10BASE-T applications.

Applications

• Network Interface Cards (NICs)
• Embedded systems with Ethernet connectivity
• Routers and switches
• Set-top boxes
• Printers

Features

• Supports 100BASE-TX and 10BASE-T operations
• Compliant with IEEE 802.3u standards
• MII interface for MAC connectivity
• Auto-negotiation for automatic speed and duplex selection
• Automatic polarity correction
• Low power consumption
• Built-in loopback test capability
• Integrated filters to reduce EMI

Benefits

• Provides a reliable and cost-effective solution for Fast Ethernet connectivity
• Simplifies system design with its integrated features
• Ensures interoperability with other Ethernet devices through compliance with IEEE standards
• Reduces power consumption in low-activity states
• Enhances system reliability with its built-in diagnostic capabilities

Technical Specifications

The RTL8251CA supports both full-duplex and half-duplex operation at 100 Mbps and 10 Mbps. It operates from a 3.3V power supply. The chip integrates transmit and receive filters to minimize external component count. It is typically available in a 48-pin QFN package.

The auto-negotiation function allows the RTL8251CA to automatically detect the speed and duplex mode of the link partner, simplifying network configuration and ensuring compatibility with various network devices. The automatic polarity correction feature automatically corrects any wiring errors, further simplifying installation and maintenance.