LT4256-3

1

42563f

The LT

allows a board to be safely inserted and removed from a

live backplane. An internal driver controls the high side

N-channel MOSFET gate for supply voltages ranging from

10.8V to 80V. The part features an open-circuit detect

(OPEN) output that indicates abnormally low load current

conditions.

The LT4256-3 also features an adjustable analog foldback

current limit. If the supply remains in current limit for more

than a programmable time, the N-channel MOSFET shuts

off, the PWRGD output asserts low and the LT4256-3

either automatically restarts after a time-out delay or

latches off until the UV pin is cycled low (depending on the

status of the RETRY pin).

The PWRGD output indicates when the output voltage

rises above a programmed level. An external resistor

overvoltage protection.

The LT4256-3 is available in a 16-lead SSOP package.

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Hot Board Insertion

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Electronic Circuit Breaker/Power Bussing

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Industrial High Side Switch/Circuit Breaker

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24V/48V Industrial/Alarm Systems

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Ideally Suited for 12V, 24V and 48V Distributed

Power Systems

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48V Telecom Systems

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

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Allows Safe Board Insertion and Removal from a

Live Backplane

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Controls Supply Voltage from 10.8V to 80V

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Foldback Current Limiting

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Open Circuit and Overcurrent Fault Detect

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Drives an External N-Channel MOSFET

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Automatic Retry or Latched Off Operation

After Overcurrent Fault

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Programmable Supply Voltage Power-Up Rate

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Open MOSFET Detection

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1% Over and Undervoltage Detection Accuracy

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Available in a 16-Lead SSOP Package

Positive High Voltage

Hot Swap Controller

with Open-Circuit Detect

Hot Swap is a trademark of Linear Technology Corporation.

4256 TA01

0.020

Ω

LT4256-3

SENSE

GATE

FB

PWRGD

RETRY

UV

OV

TIMER

GND

48V

GND

(SHORT PIN)

IRF540

CMPZ5241BS

11V

4.02k

4.02k

64.9k

100

Ω

4.02k

10

Ω

36.5k

PWRGD

48V

2A

51k

33nF

0.01

µF

10nF

OPEN

SMAT70A

UV = 36V

OV = 73V

PWRGD = 40V

+

48V, 2A Hot Swap Controller

50V/DIV

50V/DIV

PWRGD

50V/DIV

2.5ms/DIV

42563 TA02

INRUSH

CURRENT

500mA/DIV

CONTACT BOUNCE

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

LT4256-3 Start-Up Behavior