TMI7604R is an 4-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. TMI7604R 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 Class 5 for detection and classification of high-power PDs. The device supports single-supply operation, provides up to 50W to each port (Class 5 enabled). TMI7604R comprises internal temperature monitoring and thermal protection to protect against junction overheating. TMI7604R has a maximum power setting pin. Connect a resistor from this pin to AGND to set the total power capability on all 4 output ports. TMI7604R will limit the total power on 4 ports below this power limit. The 3.3V regulator is built-in to support external devices. Multiple TMI7604Rs can integrate to build an 4 x N ports PSE system, and I2C bus uses to collect PD power status from each TMI7604R to support global power managements. Management switch host has options to communicate TMI7604R via I2C bus for PSE management activities. Optocouplers can be implemented to provide electrical isolations between the host and TMI7604R for signal communication.