LTC4257CS8#PBF

Overview

The LTC4257CS8#PBF is a Power over Ethernet (PoE) Powered Device controller compliant with IEEE 802.3af standards, manufactured by Analog Devices Inc. It integrates a power switch and control logic for PoE applications. The component is housed in an 8-lead SOIC package designed for surface mount technology. It operates within a supply voltage range up to 57 V and supports a current limit of 375 mA. The device features a maximum on-resistance of 2 Ohms and functions reliably across an operating temperature range from -40°C to +85°C.

Feature Summary

• Integrates IEEE 802.3af compliant Powered Device control with an internal power switch
• Supports hot insertion and reverse polarity protection for robust network connectivity
• Includes programmable current limiting and thermal shutdown for circuit safety

Applications

• IEEE 802.3af Powered Device implementations
• Network interface cards requiring PoE power
• VoIP telephones and wireless access points
• Security cameras and surveillance systems

Procurement Notes

Verify the specific suffix #PBF indicates lead-free compliance when sourcing. Confirm the SOIC-8 package type matches your PCB footprint requirements. Ensure the manufacturer is Analog Devices Inc. to guarantee specification adherence. Check availability status as distribution may vary. Validate that the component meets the required environmental temperature ratings for your specific application environment.

Selection Notes

Select this component for designs requiring strict IEEE 802.3af compliance with integrated switching capabilities. Consider the SOIC-8 package for standard surface-mount assembly processes. Evaluate the 375 mA current limit against the load requirements of the target application. Compare the 2 Ohm on-resistance impact on power efficiency relative to other available options. Ensure the operating temperature range aligns with the intended deployment conditions.

Part Context

The LTC4257 belongs to the family of PoE controllers designed for powered devices. It simplifies system design by combining classification, detection, and power switching functions. This specific variant utilizes a commercial-grade temperature range and a standard SOIC package. It serves as a core component for enabling power delivery over Ethernet cabling in various networking hardware.

Replacement Considerations

LTC4257IDD-1#PBF offers the same functionality in a DFN-8 package with an extended industrial temperature range.