LTC4257CS8#PBF

LTC®4257 is a power over Ethernet interface controller provides complete signature and power interface functions for a device operating in an IEEE 802.3af Power over Ethernet (PoE) system. This simplifies Powered Device (PD) design by incorporating the 25k signature resistor, the classification current source, input current limit with thermal foldback, Undervoltage lockout, and power good signalling, all in a single 8-pin package. By incorporating a high voltage power MOSFET on-board, this provides the system designer with reduced cost while also saving board space. Application includes IP phone power management, wireless access points, and telecom power control.

• Precision input current limit
• On-board 25K signature resistor
• Programmable classification current
• Undervoltage lockout, smart thermal protection
• Power good signal
• Maximum operating voltage is -5V (voltage with respect to GND Pin, TA = 25°C)
• Typical on-resistance is 1ohm (I = 300mA, VIN = – 48V, TA = 25°C)
• 8-lead S8 package
• Temperature rating range from 0°C to 70°C

Notes

ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party