Data Sheet

LT4423

28V, 2A Ideal Diode and Load Switch

Rev. 0

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FEATURES



Internal 200mΩ Power Path



Wide Operating Voltage Range: 1.9V to 28V



Reverse Current Protection



Load Switch Capability



Low 10µA Quiescent Current



Fast 3µs Response to Load Steps



Low 500nA Off State Current



Smooth Switchover in Diode-OR Applications



Integrated Thermal Protection



10-Lead (3mm x 2mm x 0.75mm) LDFN Package

APPLICATIONS



Schottky Diode Replacement



Battery and Wall Adapter Diode ORing



Backup Battery Diode ORing



Industrial and Consumer Hand-Held Applications

GENERAL DESCRIPTION

The LT®4423 is a 1.9V to 28V ideal diode and load switch

with integrated P-channel MOSFETs. When enabled,

15mV forward voltage regulation minimizes power

dissipation while increasing operating headroom and

efficiency compared to a Schottky diode.

Using two LT4423s in diode-OR applications provide a

seamless transfer to the highest available voltage under

varying input supply conditions. A non-enabled LT4423

blocks up to 28V in either direction or polarity while

exhibiting less than 1μA (typical) leakage current,

providing orders of magnitude improvement over

typical Schottky diodes, which leads to extended

battery life.

Fast OUT to IN reverse bias detection minimizes reverse

current, preventing undesired charging of input

batteries. The open-drain STATUS output pulls low

when the LT4423 is in shutdown, reverse bias, or under

thermal protection. Integrated thermal detection

protects from overtemperature conditions by disabling

the power path.

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SIMPLIFIED APPLICATION DIAGRAM

Figure 1. USB PD 3.0 and Back-Up Battery Supply

Figure 2. LT4423 I-V CURVE

TO LOAD

USB PD 3.0

PRIMARY

POWER SOURCE

5V TO 20V

BACK-UP

Li-Ion CELL

3.6V

ON OFF

R1

4.7kΩ

SHDN

SHDN

D1

C1

1µF

N/C

GND

IN

OUT

STATUS

LT4423

GND

IN

OUT

STATUS

LT4423

TA = 25°C

IN = 12V

2 IN2 THERMAL RELIEF

DC FORWARD VOLTAGE DROP (mV)

10

100

400

0.001

0.01

0.1

1

2