The PM8803 integrates a Power over Ethernet (PoE) interface and a current mode PWM controller to simplify the design of the power supply sections of all powered devices. The PoE/PoE+ interface includes all functions required by the IEEE 802.3at as well as detection, classification, undervoltage lockout (UVLO) and inrush current limitation.
The PM8803 specifically performs IEEE802.3at Layer 1 hardware classification, providing the system with an indication of Type 2 PSE successful detection.
The PM8803 has been designed to work with power either from the Ethernet cable or from an external power source such as a wall adapter, ensuring the priority of the auxiliary source over the PoE. The DC-DC section of the PM8803 features a programmable oscillator frequency, an adjustable slope compensation, dual complementary low-side drivers, programmable dead time and an internal temperature sensor.
The PM8803 targets high-efficiency conversion under all load conditions supporting flyback, forward, forward with active clamp converters and synchronous rectification.
- IEEE 802.3at compliant PD interface
- Works with power supplied from Ethernet LAN cables or from local auxiliary sources
- Successful IEEE802.3at Layer1 classification indicator
- Integrated 100 V, 0.45 Ω, 1 A hot-swap MOSFET
- Accurate 140 mA typ. inrush current level
- Programmable classification current
- Programmable DC current limit up to 1 A
- Integrated high voltage start-up bias regulator
- Thermal shutdown protection
- Current mode pulse width modulator
- Programmable oscillator frequency
- 80% maximum duty cycle with internal slope compensation
- Support for flyback, forward, forward active clamp, flyback with synchronous rectification