LT4321

LT4321 PoE Ideal Diode Bridge Controller Features n n n n 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. 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 unused pairs. If the power source fails or is shorted, a fast turn-off minimizes reverse current transients. Unlike discrete ideal bridge solutions, the LT4321 will operate through transients without enabling the MOSFETs on unpowered pairs. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PowerPath and LTPoE++ are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Reduces Heat, Eliminates Thermal Design Problems Maximizes Power Efficiency Less than 800µA Quiescent Operating Current Fully Compatible with IEEE 802.3 Detection and Classification n 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++™ n 100V Absolute Maximum Voltage...