TMI7608S is an 8-port PSE (Power Sourcing  Equipment) controller IC for PoE (Power over  Ethernet) systems. It integrates power, analog and  logic circuits into a single chip, and can be used for  Midspans and Endpoint PSE applications.  TMI7608S meets all IEEE 802.3AF-2003  requirements, such as multi-point resistor detection,  PD classification, DC Disconnect, and Back-off for  Midspans. It also meets all IEEE 802.3AT-2009  requirements, such as two-event classification and  supply maximum 36W per port. The device also  supports Class4+ for detection and classification  of high-power PDs. The device supports singlesupply operation, provides up to 50W to each port  (Class4+ enabled). TMI7608S comprises internal temperature  monitoring and thermal protection to protect  against junction overheating.  TMI7608S has a maximum power setting pin.  Connect a resistor from this pin to AGND to set the  total power capability on all 8 output ports.  TMI7608S will limit the total power on 8 ports below  this power limit. The 3.3V regulator is built-in to support external  devices. Multiple TMI7608Ss can integrate to build  an 8 x N ports PSE system, and I2C bus uses to  collect PD power status from each TMI7608S to  support global power managements. Management  switch host has options to communicate TMI7608S via I2C bus for PSE management activities.  Optocouplers can be implemented to provide  electrical isolations between the host and  TMI7608S for signal communication