16 10 17 9 18 8 19 7 20 6 Si3480 Si3480 POWER MANAGEMENT CONTROLLER Features Enables use of a smaller power Pin programmable for overall supply for a 4 or 8 port PoE power supply capacity, port system power level, port priority, and detection timing Self-contained solution operates without the need for a host for LED indication of port status and unmanaged operation overall power consumption No software required 20-pin Quad flat package No data isolation required (4x4 mm) Ordering Information: 4x4 mm PCB footprint RoHS Fully compliant with IEEE 802.3 compliant clause 33 for Power over Ethernet See Ordering Guide on page 9. Extended operating temperature including the 802.3at amendment range (40 to +85 C) for higher power (30 W category 2 ports) Pin Assignments Description (Top View) The Si3480 is a power manager intended for use with the Si3452 Power over Ethernet (PoE) controller. The Si3480 enables the use of a smaller, lower cost, and more efficiently-utilized power supply in an unmanaged PoE Power Sourcing Equipment (PSE) system. SDA 1 15 PRIOCFG The Si3452 is capable of delivering over 30 W per port, which means that, GND 2 14 ALTCFG in a typical 8-port system, a 240 W power supply would have to be used VDD 3 13 LED8 to avoid overload. Typically, not all ports are used at full power so, a RST 4 12 LED7 smaller power supply in the range of 30 to 150 W can be used along with NC 5 11 LED6 the Si3480 power management controller. The Si3480 power management controller is pin programmed. The pins are used to set the power supply capacity, the number of low power (category 1, 15.4 W), and high power (category 2, 30 W) ports, the port priority, and the detection timing (Alternative A or Alternative B). The Si3480 uses the real time overload and current monitoring capability of the Si3452 to manage power for up to eight ports. Power management is based on actual consumption rather than mere classification in order to supply power to the greatest number of ports. The Si3480 also provides LED drive to indicate port status and drive an LED bar graph display to indicate the power supply capacity in use. If a port is denied power due to power supply capacity limitations, the LED indicators provide a simple and intuitive indication, helping a user recognize and correct the overload situation by rebalancing loads or adding mid-span power injectors to ports that would not otherwise be powered. In case of a port overload, the port is easily re-enabled by disconnecting the Powered Device (PD) and then reconnecting the PD after correcting the overload situation. Rev. 1.1 1/15 Copyright 2015 by Silicon Laboratories Si3480 Not Recommended for New Designs LED1 SCL LED2 INT LED3 LEDBANK LED4 PWRCFG LED5 POECFGSi3480 Functional Block Diagram Configuration Pins Power Provided Si3480 Port Power Power Port Priority Si3452 Management Detection Timing PoE Controller Controllers Port Power Status Meter LEDs LEDs 2 Rev. 1.1 Not Recommended for New Designs