ANALOG DEVICES LT4321HUF#PBF Ideal Diode Bridge Controller, Dual, Power Over Ethernet, 20 to 80 V, -40 to 125 Deg C, QFN-EP-16

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 to eliminate larger and more costly PMOS switches. This works with 2-pair and 4-pair applications. Application includes PoE/PoE+/PoE++/LTPoE++ powered devices, DC polarity correction and ideal diode-ORing of telecom supplies.

• Reduces heat, eliminates thermal design problems
• Maximizes power efficiency
• 100V absolute maximum voltage
• Operating supply range from 20 to 70V ( IN12 � IN36 , IN45 � IN78 , OUTP, TA = 25°C)
• Typical undervoltage lockout is 17V (OUTP � OUTN, TA = 25°C)
• Typical top gate drive is 9.5V (INn = OUTP + ?VSD(MAX) + 5mV, 10µA Out of TGn, TA = 25°C)
• Typical bottom gate drive is 11.5V (10µA Out of BGn, TA = 25°C)
• Minimum top gate pull-down current is 1.25mA (INn = OUTP � 0.25V; TGn � INn = 5V, TA = 25°C)
• 16-lead plastic QFN package
• Temperature rating rage from -40°C to 125°C

Notes

ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party