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LTC4274A/LTC4274C - Single PoE/PoE+/LTPoE++ PSE Controller

The LTC®4274A is a single Power Sourcing Equipment (PSE) controller capable of delivering up to 90W of LTPoE++ power to a compatible LTPoE++ Powered Device (PD). A proprietary detection/classification scheme allows mutual identification between a LTPoE++ PSE and LTPoE++ PD while remaining compatible and interoperable with existing Type 1 (13W) and Type 2 (25.5W) PDs. The LTC4274A feature set is a superset of the popular LTC4274. These PSE controllers feature low-RON external MOSFETs and 0.25Ω sense resistors which are especially important at the LTPoE++ current levels to maintain the lowest possible heat dissipation.

The LTC4274C targets fully automatic PSE systems powering Type 1 (up to 13W) PDs.

Advanced power management features include: a 14-bit current monitoring ADC, DAC-programmable current limit, and versatile quick port shutdown. PD Discovery uses a proprietary dual-mode 4-point detection mechanism ensuring excellent immunity from false PD detection. The LTC4274A/LTC4274C includes an I2C serial interface operable up to 1MHz.

The LTC4274A/LTC4274C is available in multiple power grades, allowing delivered PD power of 13W, 25.5W, 38.7W, 52.7W, 70W and 90W. These controllers are available in a 38-lead 5mm × 7mm QFN package.

Features Compliant with IEEE 802.3at Type 1 and 2 Low Power Dissipation 0.25Ω Sense Resistance Per Channel Very High Reliability 4-Point PD Detection 2-Point Forced Voltage 2-Point Forced Current High Capacitance Legacy Device Detection 1MHz I2C Compatible Serial Control Interface Midspan Backoff Timer Supports 2-Pair and 4-Pair Output Power Available in Multiple Power Grades LTC4274A-1: LTPoE++™ 38.7W LTC4274A-2: LTPoE++ 52.7W LTC4274A-3: LTPoE++ 70W LTC4274A-4: LTPoE++ 90W LTC4274C: PoE 13W Available in 38-Lead 5mm × 7mm QFN Package Typical Application

Applications LTPoE++ PSE Switches/Routers LTPoE++ PSE Midspans IEEE 802.3at Type 1 PSE Switches/Routers IEEE 802.3at Type 1 PSE Midspans Packaging

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