The LTC4257CDD-1#PBF is a sophisticated integrated circuit from Linear Technology, designed for Power over Ethernet (PoE) applications. This IC is specifically tailored to serve as a Power Sourcing Equipment (PSE) controller, enabling it to supply power to PoE devices through Ethernet cables, following the IEEE 802.3af standard. It is housed in a compact DFN package, making it suitable for space-constrained applications.

Key Features

• IEEE 802.3af Compliant: The LTC4257CDD-1#PBF adheres to the stringent requirements of the IEEE 802.3af standard, ensuring compatibility with a wide range of PoE-capable devices.
• Integrated Power MOSFET: This PSE controller includes an internal power MOSFET, which simplifies the design and reduces external component count.
• Automatic Classification: The device supports the detection and classification of powered devices (PDs), enabling it to allocate the appropriate power levels.
• Overcurrent Protection: With built-in overcurrent protection, the LTC4257CDD-1#PBF prevents damage to the power supply and connected devices in the event of a fault condition.
• Thermal Shutdown: The thermal shutdown feature ensures the device operates within safe temperature limits, offering additional protection.

Applications

The LTC4257CDD-1#PBF is ideal for a variety of applications where PoE is required. It is commonly used in:

• Network switches and routers
• IP cameras and security systems
• Wireless access points
• VoIP phones
• Industrial control systems

Technical Specifications

The device operates over a supply voltage range of 44V to 57V, which is typical for PoE applications. It is available in a 10-lead (3mm × 3mm) DFN package, providing a compact solution for PSE controllers. The LTC4257CDD-1#PBF also includes features such as undervoltage lockout, leading-edge blanking, and a classified current limit to ensure reliable and safe operation.

With its robust feature set and compliance with PoE standards, the LTC4257CDD-1#PBF from Linear Technology is an excellent choice for designers looking to implement PoE capabilities in their networking and communication devices.