LTC4255

1

4255f

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Controls Four Independent –48V Power Channels

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Each Channel has Separate Relay Drivers, ON/OFF

Control, Short-Circuit Protection with Current

Foldback, Open-Circuit Detection, and Power Good

Indication

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Five Bit Programmable Digital Address Allows

Control of up to 32 LTC4255s (128 Channels)

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Interrupt on FAULT Output can be used to Eliminate

Software Polling

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Programmable Current Limit and Open-Circuit

Duration Periods

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Programmable Latchoff or Autoretry after Short-

Circuit Faults

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Programmable Autoretry Duty Cycle

Quad Network Power

The LTC

face. Each channel can be turned on and off via software

control, while providing short-circuit protection, open-

circuit detection, and power good indication. The short-

circuit protection includes a current foldback feature to

reduce power dissipation in the switch during shorts and

start-up.

The serial interface allows up to 128 channels to be

controlled with only two digital lines. A FAULT output can

be used as an interrupt line to eliminate fault detection by

software polling.

External switches and current sense resistors allow easy

scaling of current and power dissipation levels and pro-

vide the maximum protection against voltage and current

spikes.

The LTC4255 is available in the 28-pin SSOP package.

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

0.33

Ω

0.33

Ω

0.33

Ω

0.33

Ω

Q1

Q2

Q3

Q4

12V

0.1

µF

–48V

4255 TA01

100k

100k

100k

100k

SCL

SDA

FAULT

AD0

AD1

AD2

AD3

AD4

DGND AGND

SENSE1 GATE1

OUT1 SENSE2 GATE2

OUT2 SENSE3 GATE3

OUT3 SENSE4 GATE4 OUT4

RELAY1

RELAY2

RELAY3

RELAY4

LTC4255

0.1

µF

Q1, Q2, Q3, Q4: FDC3612

RELAYS: V23079 SERIES

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IP Phone Systems

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DTE Power Distribution

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO