MP3924 IEEE 802.3af/at PSE Controller QFN-32

MP3924 IEEE 802.3af/at PSE Controller QFN-32

The MP3924 is a quad-port power source equipment (PSE) power controller for IEEE 802.3af/at compliant power over Ethernet (PoE) applications.

Key Specifications

Features

• IEEE802.3af/at Compliant
• Quad-Port and 4-Bit Configurable I2C Address
• 0.25Ω Current-Sense Resistor
• Automatic Mode and I2C Command Control Mode
• Automatic Input Over-Power Shutdown
• Internal VCC Power Supply
• Three-Wire I2C Interface for Isolated Applications
• Two INT Pins for Interrupt Priority Selection
• Disconnected DC Load Detection
• Instantaneous Current/Voltage Readout

Typical Application Circuit

Applications

• PSE Switches/Routers
• PSE Midspan Power Injectors

Design Notes

• Rail sequencing order and delay are part of the SoC power-up contract; a wrong order latches the processor even though every rail is in spec.
• In multiphase designs, current balance depends on the loop matching between phases, so keep the layout symmetric.
• Digital interfaces (PMBus, I²C) need pull-ups to the correct rail and a defined state during power-up.
• Thermal design is a system problem here: the PMIC sits next to the load it feeds, so budget the shared copper, not the package alone.

Common Questions