LT4321
PoE Ideal Diode Bridge
Controller
Features Description n n n The LTВ®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. Reduces Heat, Eliminates Thermal Design Problems
Maximizes Power Efficiency
Less than 800ВµA Quiescent Operating Current
Fully Compatible with IEEE 802.3 Detection and Classificatio IEEE 802.3 Compliant When Paired with a Powered Device (PD) Controller
n Works with 2-Pair and 4-Pair PoE Applications
n Compatible with PoE, PoE+, and LTPoE++в„ў
n 100V Absolute Maximum Voltage
n H-Grade Version Operates Up to 125В°C
n 16-Lead 4mm Г— 4mm QFN Package
n Applications PoE/PoE+/ LTPoE++ Powered Devices DC Polarity Correction and Ideal Diode-ORing of
Telecom Supplies An internal charge pump allows an all-NMOS bridge
eliminating larger and more costly PMOS switches. The
LT4321 works with 2-pair and 4-pair applications. High
impedance input sense pins prevent reverse current on …