LM74681中文資料德州儀器數(shù)據(jù)手冊PDF規(guī)格書

1 Features

? Input operating voltage range: 30V to 90V

– 100V absolute maximum

? 4× integrated gate drive control

? 165μA gate pull-up strength

? 100mA gate pull-down strength

? Ultra-low quiescent current of 0.27μA during

detection and classification phase (VIN1-IN2 < 23V)

? Linear gate regulation control for supply ORing

applications

– VTG_REG = 11mV

? Enable pin for user controlled device on/off

function

? –40°C to 125°C operating junction temperature

range

? Small footprint: 3mm × 3mm WSON-12

– Meets IPC-9592 spacing rules

2 Applications

? PoE powered devices (48V)

? Video surveillance: IP cameras

? Polarity agnostic power inputs

3 Description

The LM74681 is a 100V ideal diode bridge controller

capable of driving a MOSFET bridge, enabling

efficient low-loss bridge rectifier solutions in Power

over Ethernet (PoE) applications. It allows a Power

over Ethernet, powered device (PD) to receive

power from RJ-45 data pairs, spare pairs, or any

combination of the two, regardless of voltage polarity.

The integrated charge pump allows use of N-channel

MOSFETs, which are smaller and more cost effective

than P-channel MOSFETs for the same power level.

The LM74681 along with N-channel MOSFET bridge

can replace the conventional diode bridge and can

be conveniently implemented in both 2-pair and 4-

pair PoE PD systems. In the event of a power

source failure or short circuit, a rapid turn-off feature

reduces reverse current spikes. The device also

features an ultra-low quiescent current of 0.27μA,

which ensures that there is no data corruption during

the PoE PD detection and classification phase. This

device is characterized for operation over a junction

temperature range of –40°C to +125°C.