LTC4258 Series

Quad IEEE 802.3af Power over Ethernet Controller with Integrated Detection

Catalog

Quad IEEE 802.3af Power over Ethernet Controller with Integrated Detection

Part	Type	Auxiliary Sense	Operating Temperature [Max]	Operating Temperature [Min]	Standards	Package / Case	Package / Case [y]	Package / Case [y]	Power - Max [Max]	Internal Switch(s)	Number of Channels	Supplier Device Package	Mounting Type	Current - Supply	Voltage - Supply [Min]	Voltage - Supply [Max]
Analog Devices LTC4258CGW#PBF	Controller (PSE)		70 °C	0 °C	802.3af (PoE)	36-BSOP	0.295 in	7.5 mm	15.4 W		4	36-SSOP	Surface Mount	2 mA	47 V	57 V

Catalog

Quad IEEE 802.3af Power over Ethernet Controller with Integrated Detection

Key Features

• Controls Four Independent -48V Powered Ethernet Ports

• Each Port Includes:IEEE 802®.3af Compliant PD Detection and ClassificationOutput Current Limit with FoldbackShort-Circuit Protection with Fast Gate Pull-DownPD Disconnect Using DC SensingPower Good Indication Operates Autonomously or by I2C™Control

• IEEE 802®.3af Compliant PD Detection and Classification

• Output Current Limit with Foldback

• Short-Circuit Protection with Fast Gate Pull-Down

• PD Disconnect Using DC Sensing

• Power Good Indication Operates Autonomously or by I2C™Control

• 4-Bit Programmable Digital Address Allows Control of Up to 64 Ports

• ProgrammableINTPin Eliminates Software Polling

• Current and Duty Cycle Limits Protect External FETs

• Available in a 36-Pin SSOP Package

Description

The LTC4258 is a quad –48V Hot Swap™controller designed for use in IEEE 802.3af compliant Power Sourcing Equipment (PSE). It consists of four independent ports, each with output current limit, short-circuit protection, complete Powered Device (PD) detection and classification capability, and programmable PD disconnect using DC sensing. Used with power MOSFETs and passives as in Figure 1, the LTC4258 can implement a complete IEEE 802.3af-compliant PSE.The LTC4258 can operate autonomously or be controlled by an I2C serial interface. Up to 16 LTC4258s may coexist on the same data bus, allowing up to 64 powered Ethernet ports to be controlled with only two digital lines. Fault conditions are optionally signaled with theINTpin to eliminate software polling.External power MOSFETs, current sense resistors and diodes allow easy scaling of current and power dissipation levels and provide protection against voltage and current spikes and ESD events.The LTC4258 is available in a 36-pin SSOP package.Analog Devices also provides solutions for 802.3af PD applications with the LTC4257, LTC4257-1, and LTC4267.ApplicationsIEEE 802.3af Compliant Endpoint and Midspan Power SourcesIP Phone SystemsDTE Power Distribution