LTC4274A Datasheet | Linear Technology

Features nn pliant with IEEE 802.3at Type 1 and 2 nn Low Power Dissipation nn 0.25Ω Sense Resistance Per Channel nn Very High Reliability 4-Point PD Detection nn 2-Point Forced Voltage nn 2-Point Forced Current nn High Capacitance Legacy Device Detection nn 1MHz I2C patible Serial Control Interface nn Midspan Backoff Timer nn Supports 2-Pair and 4-Pair Output Power nn Available in Multiple Power Grades nn LTC4274A-1: LTPo E++™ 38.7W nn LTC4274A-2: LTPo E++ 52.7W nn LTC4274A-3: LTPo E++ 70W nn LTC4274A-4: LTPo E++ 90W nn LTC4274C: Po E 13W nn Available in 38-Lead 5mm × 7mm QFN Package APPLICATIONS nn LTPo E++ PSE Switches/Routers nn LTPo E++ PSE Midspans nn IEEE 802.3at Type 1 PSE Switches/Routers nn IEEE 802.3at Type 1 PSE Midspans L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and LTPo E++ are trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners. LTC4274A/LTC4274C Single Po E/Po E+/LTPo E++ PSE Controller DESCRIPTION The LTC®4274A is a single Power Sourcing Equipment (PSE) controller capable of delivering up to 90W of LTPo E++ power to a patible LTPo E++ Powered Device (PD). A proprietary detection/classification scheme allows mutual identification between a LTPo E++ PSE and LTPo E++ PD while remaining patible 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 LTPo E++ 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...