LTC4355



4355fa

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Typical applicaTion

FeaTures

applicaTions

DescripTion

Positive High Voltage

Ideal Diode-OR with Input Supply

and Fuse Monitors

that drives two external N-channel MOSFETs. Forming the

diode-OR with N-channel MOSFETs instead of Schottky

diodes reduces power consumption, heat dissipation and

PC board area.

With the LTC4355, power sources can easily be ORed

together to increase total system reliability. The LTC4355

can diode-OR two positive supplies or the return paths of

two negative supplies, such as in a –48V system.

In the forward direction the LTC4355 controls the voltage

dropacrosstheMOSFETtoensuresmoothcurrenttransfer

from one path to the other without oscillation. If a power

source fails or is shorted, fast turnoff minimizes reverse

current transients.

Power fault detection indicates if the input supplies are

not in regulation, the inline fuses are blown, or the

voltages across the MOSFETs are greater than the fault

threshold.

+48V Diode-OR

■

Replaces Power Schottky Diodes

■

Controls N-Channel MOSFETs

■

0.5µs Turn-Off Time Limits Peak Fault Current

■

Wide Operating Voltage Range: 9V to 80V

■

Smooth Switchover without Oscillation

■

No Reverse DC Current

■

■

Available in 14-Lead (4mm

× 3mm) DFN and

16-Lead SO Packages

■

High Availability Systems

■

■

+48V and –48V Distributed Power Systems

■

Telecom Infrastructure

Power Dissipation vs Load Current

4355 TA01

LTC4355

GND

GATE1

GATE2

IN1

OUT

IN2

MON1

MON2

SET

12.7k

340k

12.7k

340k

7A

22k

22k

22k

22k

22k

GREEN LEDs

PANASONIC LN1351C

7A

GND

FDB3632

FDB3632

TO

LOAD

VDSFLT

FUSEFLT1

FUSEFLT2

PWRFLT1

PWRFLT2

CURRENT (A)

0

0

1

2

3

4

5

6

2

4

6

8

4355 TA02

10

DIODE (MBR10100)

FET (FDB3632)

POWER

SAVED

SPELL CHECK COMPLETED