LTC4269-2 Datasheet

• 25.5W IEEE 802.3at Compliant (Type-2) PD
• PoE⁺ 2-Event Classification
• IEEE 802.3at High Power Available Indicator
• Integrated State-of-the-Art Synchronous Forward Controller
• – Isolated Power Supply Efficiency >94%
• Flexible Auxiliary Power Interface
• Superior EMI Performance
• Robust 100V 0.7Ω (Typ) Integrated Hot Swap^™ MOSFET
• Integrated Signature Resistor, Programmable Class Current, UVLO, OVLO and Thermal Protection
• Short-Circuit Protection with Auto-Restart
• Programmable Switching Frequency from 100kHz to 500kHz
• Thermally Enhanced 7mm × 4mm DFN Package

• IP Phones with Large Color Screens
• Dual Radio 802.11n Access Points
• PTZ Security Cameras

The LTC4269-2 is an integrated Powered Device (PD) interface and power supply controller featuring 2-event classification signaling, flexible auxiliary power options, and a power supply controller suitable for synchronously rectified forward supplies. These features make the LTC4269-2 ideally suited for an IEEE802.3at PD application.

The PD controller features a 100V MOSFET that isolates the power supply during detection and classification, and provides 100mA inrush current limit. Also included are power good outputs, an undervoltage/overvoltage lockout and thermal protection. The current mode forward controller allows for synchronous rectification, resulting in an extremely high efficiency, green product. Soft-start for controlled output voltage start-up and fault recovery is included. Programmable frequency over 100kHz to 500kHz allows flexibility in efficiency vs size and low EMI.