Analog Devices LTC4291-1

Description

The LTC®4291-1/LTC4292 chipset is a 4-port power sourcing equipment (PSE) controller designed for use in IEEE 802.3bt Type 3 and 4 compliant Power over Ethernet (PoE) systems. The LTC4291-1/LTC4292 is designed to power compliant 802.3af, 802.3at, and 802.3bt PDs. The LTC4291-1/LTC4292 chipset delivers lowest-in-indus¬try heat dissipation by utilizing low RDS(ON) external MOSFETs and 0.15Ω sense resistance per power channel. A transformer-isolated communication protocol replaces expensive opto-couplers and complex isolated 3.3V sup¬ply, resulting in significant BOM cost savings. Advanced power management features include per-port 14 bit current monitoring, programmable current limit, and versatile fast shutdown of preselected ports. Advanced power management host software is available under a no-cost license. PD detection uses a proprietary multipoint detection mechanism ensuring excellent immunity from false PD identification. Autoclass and 5-event physical classification are supported. The LTC4291-1/LTC4292 includes an I2C serial interface operable up to 1MHz. The LTC4291-1/LTC4292 is pin or I2C programmable to nego¬tiate PD delivered power up to 71.3W.

Features

• Four PSE Ports nnTwo Power Channels per Port
• Fully Compliant IEEE 802.3bt Type 3 and 4 PSE
• Compliant Support for Type 1, 2, 3, and 4 PDs
• Low Power Path Dissipation per Channel
• 150mΩ Sense Resistance
• 30mΩ or Lower MOSFET RDS(ON)
• Chipset Provides Electrical Isolation
• Eliminates Optos and Isolated 3.3V Supply
• Very High Reliability Multipoint PD Detection
• Connection Check Distinguishes Single- Signature and Dual-Signature PDs
• Continuous, Dedicated Per-Port Power and Current Monitoring
• Per-Port Power Policing
• 1MHz I2C Compatible Serial Control Interface
• Pin or I2C Programmable PD Power Up to 71.3W
• Available in a 40-Lead 6mm × 6mm (LTC4292) and 24-Lead 4mm × 4mm (LTC4291-1) QFN Packages

Typical applications

• PoE PSE Switches/Routers, PoE PSE Midspans

More information

• Datasheet
• IC product information