DescripTion
The LT®4321 is a dual ideal diode bridge controller that enables a Power over Ethernet (PoE) powered device (PD) to receive power in either voltage polarity from RJ-45 data pairs, spare pairs, or both. The LT4321 and eight N-channel MOSFETs replace the eight diodes in a passive PoE rectifier bridge. The LT4321 eases thermal design and increases delivered power.

FEATUREs
■ Reduces Heat, Eliminates Thermal Design Problems
■ Maximizes Power Efficiency
■ Less than 800µA Quiescent Operating Current
■ Fully Compatible with IEEE 802.3 Detection and
   Classification
■ IEEE 802.3 Compliant When Paired with a Powered
   Device (PD) Controller
■ Works with 2-Pair and 4-Pair PoE Applications
■ Compatible with PoE, PoE+, and LTPoE++™
■ 100V Absolute Maximum Voltage
■ H-Grade Version Operates Up to 125°C
■ 16-Lead 4mm × 4mm QFN Package

APPLICATIONs
■ PoE/PoE+/ LTPoE++ Powered Devices
■ DC Polarity Correction and Ideal Diode-ORing of
   Telecom Supplies