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LTC4255 Quad Network Power Controller with I2C Compatible Interface
FEATURES
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DESCRIPTIO
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Controls Four Independent –48V Power Channels Each Channel has Separate Relay Drivers, ON/OFF Control, Short-Circuit Protection with Current Foldback, Open-Circuit Detection, and Power Good Indication Programmed via I2CTM Compatible Interface Five Bit Programmable Digital Address Allows Control of up to 32 LTC4255s (128 Channels) Interrupt on FAULT Output can be used to Eliminate Software Polling Programmable Current Limit and Open-Circuit Duration Periods Programmable Latchoff or Autoretry after ShortCircuit Faults Programmable Autoretry Duty Cycle
The LTC®4255 is a quad –48V network power controller with independent relay drivers and I2C compatible interface. Each channel can be turned on and off via software control, while providing short-circuit protection, opencircuit detection, and power good indication. The shortcircuit 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 provide 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. I2C is a trademark of Philips Electronics N.V.
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IP Phone Systems DTE Power Distribution
TYPICAL APPLICATIO
12V
0.1µF
VCC SCL SDA FAULT AD0 AD1 AD2 AD3 AD4 DGND AGND VEE SENSE1 GATE1 RELAY3 RELAY4 OUT1 SENSE2 GATE2 OUT2 SENSE3 GATE3 OUT3 SENSE4 GATE4 OUT4 100k Q1 RS2 0.33Ω Q2 RS3 0.33Ω Q3 Q1, Q2, Q3, Q4: FDC3612 RELAYS: V23079 SERIES RS4 0.33Ω Q4
4255f
LTC4255
–48V
RS1 0.1µF 0.33Ω
100k
100k
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RELAY1 RELAY2 100k
4255 TA01
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LTC4255
ABSOLUTE
(Note 1)
AXI U RATI GS
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TOP VIEW FAULT SCL SDA AD4 AD3 AD2 AD1 AD0 RELAY1 1 2 3 4 5 6 7 8 9 28 OUT1 27 GATE1 26 SENSE1 25 OUT2 24 GATE2 23 SENSE2 22 VEE 21 OUT3 20 GATE3 19 SENSE3 18 OUT4 17 GATE4 16 SENSE4 15 AGND
Supply Voltages VCC to DGND ....................................................... 18V VEE to AGND ...................................................... –80V DGND to AGND ................................................... ±5V Digital Pin Voltages SCL, SDA, FAULT ........................ DGND – 0.3V to 6V AD0-4 ....................................... DGND – 0.3V to 5.5V Relay Driver Output Voltage RELAY1-4 (Note 5) ...... DGND –0.3V to DGND + 15V Analog Voltages SENSE1-4 ............................... VEE – 0.3V to VEE + 1V OUT1-4 .................................. VEE – 80V to VEE + 80V Operating Temperature Range LTC4255C ...................................