LTC4257CS8-1#PBF

LTC4257-1 is a EEE 802.3af PD power over ethernet interface controller with dual current limit. It provides complete signature and power interface functions for a device operating in an IEEE 802.3af power over ethernet (PoE) system. It simplifies powered device (PD) design by incorporating the 25K signature resistor, classification current source, input current limit, undervoltage lockout, thermal overload protection, signature disable and power good signalling, all in a single 8pin package. It includes a precision, dual level current limit circuit. This allows it to charge large load capacitors and interface with legacy power over ethernet systems while maintaining compatibility with the current IEEE 802.3af specification. By incorporating a high voltage power MOSFET onboard, it provides the system designer with reduced cost while also saving board space. It is used in applications such as IP phone power management, wireless access points, telecom power control etc.

• Onboard 100V, 400mA power MOSFET
• Precision dual level current limit
• Programmable classification current (class 0-4)
• Undervoltage lockout, power good signal
• Thermal overload protection
• On-resistance is 1 ohm typical at (I = 350mA, VIN = -48V, measured from VIN to VOUT)
• Operating temperature range from 0°C to 70°C
• Package style is 8-lead NSOIC

注释

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