12 19 11 20 10 21 9 22 8 23 24 7 Si3482 POWER MANAGEMENT CONTROLLER Features Pin Assignments 24-Pin QFN Enables use of smaller power Supports classification-based and supplies for up to 48-port PoE LLDP power negotiation systems with Si3452 PSE interface Supports individual port priority and ICs port configuration MISO 1 Can operate with or without a host Supports Power supply status from 18 SDA Configuration save up to 3 power supplies SCK 2 17 SCL Pin-selectable SPI or UART interface 24 pin Quad flat pack package 3 GND 16 BAUD0 Pin-selectable UART data rate (4x4 mm) Top View (Pads on Bottom of Package) 4 VDD 15 Fully-compliant with IEEE 802.3 4x4 mm PCB footprint RoHS BAUD1 clause 33 for PoE including the complaint 5 RST 14 BAUD2 802.3at amendment for higher power Extended operation range 6 RSVD 13 PSLCT (30 W, category 2 ports) (40 to +85 C) Applications Power over Ethernet Endpoint Industrial automation systems See5. Pin Description on page 31. switches and Midspans for IEEE Std Networked audio 802.3af and 802.3at IP Phone Systems and iPBXs Supports high-power PDs, such as: Metropolitan area networked WAPs, Pan/Tilt/Zoom security cameras cameras, and sensors 802.11n WAPs WiMAX, ASN/BTS, and CPE/ODU Multi-band, multi-radio WAPs systems Security and RFID systems Description The Si3452 is capable of delivering over 30 W per port, which means that, in a 24- or 48-port system, a very large power supply would have to be used to avoid overload. Typically, not all ports are used at full power so, a smaller power supply in the range of 5W per port can be used along with the Si3482 power management controller. The Si3482 is a power manager intended for use with the Si3452/3 Power over Ethernet (PoE) controllers for power management of up to 48 ports with three power sources. Use of the Si3482 power manager greatly simplifies system implementation of power management. The Si3482 power management controller is programmed via a SPI or UART interface to set the power supply capacity, the port power configuration (Category 1: 15.4 W, or high-power category 2: 30 W) ports, the port priority, the detection timing (Alternative A or Alternative B), and the fault recovery protocol. Once programmed, the configuration data can be saved, and the Si3482 can work without host intervention. If desired, port and overall status information is available and continuously updated. The Si3482 uses the real-time overload and current monitoring capability of the Si3452 to manage provided power among up to 48 ports. Power management is selectable between grant-based or consumption-based in order to supply power to the greatest number of ports. In high-reliability systems, multiple power supplies are often connected to provide redundancy, which further increases the power supply requirements. The Si3482 can manage up to three power supplies automatically enabling or disabling ports in priority order when required. Rev. 0.1 10/10 Copyright 2010 by Silicon Laboratories Si3482 MOSI RSVD RSVD NSS RSVD TX RX PS3 PS2 RSVD PS1 INTSi3482 Functional Block Diagram 2 Rev. 0.1