GENERAL DESCRIPTION

The LT®8673 is an active rectifier controller for reverse

input protection that includes two independent low IQ

comparators with programmable glitch rejection filters

for cold start pulse detection and two voltage monitoring

protection pins to sense the battery voltage safely using

an external resistive divider and ADC (analog-to-digital

converter). The highly integrated comparators and active

rectifier solution greatly simplify the Bill of Materials

(BOM) and shrinks the printed circuit board (PCB) area.

The controller drives an external N-channel Metal-oxide

semiconductor field-effect transistor (MOSFET) to replace

a power Schottky diode. Its very low quiescent current

and fast transient response meet the tough requirements

in automotive applications where AC input signals of up

to 100kHz are present. These signals are rectified with

minimum power dissipation on the external MOSFET,

simplifying thermal management on the PCB.

With a drop of only 20mV, the LT8673 solution eases the

minimum input voltage requirement during cold crank

and start-stop, allowing simpler and more efficient circuits.

A fast turn-off minimizes reverse current transients

if the input power source fails or is shorted. An available

shutdown mode reduces the quiescent current to 3.8μA.

An integrated auxiliary boost regulator provides the

required boost voltage to turn the external MOSFET fully

on. A FAULT pin signals if the external FET is not ready to

take load current.

FEATURES

 Reverse Input Protection to -40V

 Improved Performance Compared to a Schottky

Diode

 Reduce Power Dissipation by > 90

 Reduce Drop to 20mV

 Ultrafast Transient Response

Rectifies 6VP-P Up to 50kHz

Rectifies 2VP-P Up to 100kHz

 Wide Operating Voltage Range: 3V to 42V

 Two Integrated Comparators for Cold Crank

Detection

 Programmable Anti-glitch Filters

 Dedicated Enable Pin (ENR)

 Voltage Monitoring Protection Pins

 Low 55μA Quiescent Current in Operation

 Low 3.8μA Shutdown Current

 Accurate 1.2V Enable Pin Threshold

 Small 20-Lead 3mm x 4mm Side-Wettable Quad Flat

No-Lead (QFN) Package

 AEC-Q100 Qualified for Automotive Applications

APPLICATIONS

 Automotive Battery Protection

 Industrial Supplies

 Portable Instrumentation