LTC4257CDD#TRPBF

Overview

The LTC4257CDD#TRPBF is a Powered Device (PD) interface controller compliant with the IEEE 802.3af standard for Power over Ethernet applications. It provides complete signature and power interface functions, including detection, classification, and soft-start control. The device operates within a supply voltage range of up to 57V and features an internal current limit of 375mA. It utilizes a DFN-8 surface-mount package suitable for space-constrained designs. Operating temperatures are specified from -40°C to +85°C, ensuring reliability in industrial environments.

Feature Summary

• Provides complete signature and power interface functions for IEEE 802.3af PD systems
• Integrates detection, classification, and soft-start control mechanisms
• Supports high-voltage operation up to 57V with integrated current limiting

Applications

• IEEE 802.3af Powered Device interfaces
• PoE-powered network equipment
• Industrial communication nodes requiring PoE input

Procurement Notes

Verify the specific suffix #TRPBF indicates tape-and-reel packaging when ordering. Confirm that the CDD variant corresponds to the DFN-8 package type required for your PCB layout. Ensure compatibility with IEEE 802.3af standards for your target application. Cross-reference the manufacturer's latest datasheet for any updates to pinout or electrical characteristics before finalizing procurement.

Selection Notes

Select this component for designs requiring a fully integrated IEEE 802.3af PD solution without external discrete components for signature detection. The DFN-8 package offers a compact footprint compared to larger SOIC options. Consider the 375mA current limit when sizing downstream power stages. Verify thermal performance requirements given the operating temperature range and package thermal resistance.

Part Context

This part belongs to the Linear Technology (now Analog Devices) LTC4257 family of PoE controllers. It is specifically designed as a Powered Device controller, distinct from PSE controllers like the LTC4257 which manage power sourcing. The family includes variants with different packages and temperature grades, all adhering to the same core IEEE 802.3af interface protocol.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.