Electrical Specifications Subject to Change
LT4180
Virtual Remote Sense
Controller
FEATURES
DESCRIPTION
The LT®4180 solves the problem of providing tight load
regulation over long, highly resistive cables without
requiring an additional pair of remote sense wires. This
Virtual Remote Sense™ device continuously interrogates
the line impedance and corrects the power supply output
voltage via its feedback loop to maintain a steady voltage
at the load regardless of current changes.
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Tight Load Regulation with Highly Resistive Cables
without Requiring Remote Sense Wiring
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Compatible with Isolated and Nonisolated Power
Supplies
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1ꢀ Internal Voltage Reference
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5mA Sink Current Capability
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Soft-Correct Reduces Turn-On Transients
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Undervoltage and Overvoltage Protection
The LT4180 is a full-featured controller with 5mA opto-
isolator sink capability, under/overvoltage lockout,
soft-start and a 1ꢀ internal voltage reference. The
Virtual Remote Sense feature set includes user-program-
mable dither frequency and optional spread spectrum
dither.
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Pin-Programmable Dither Frequency
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Optional Spread Spectrum Dither
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Wide V Range: 3.1V to 50V
IN
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24-Pin SSOP Package
APPLICATIONS
The LT4180 works with any topology and type of isolated
or nonisolated power supply, including DC/DC converters
and adjustable linear regulators.
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12V High Intensity Lamps
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28V Industrial Systems
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High Power (>40 Watts) CAT5 Cable Systems
Wiring Drop Cancellation for Notebook Computer
Battery Charging
AC and DC Adaptors
Well-Logging and Other Remote Instrumentation
Surveillance Equipment
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The LT4180 is available in a 24-pin, SSOP package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Virtual Remote Sense is a trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
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TYPICAL APPLICATION
Isolated Power Supply with Virtual Remote Sense
VLOAD vs VWIRE
5.00
4.99
4.98
4.97
4.96
4.95
CAT5E CABLE
R
SENSE
LINE
LINE
+
C
L
R
L
SWITCHING
REGULATOR
V
C
V
SENSE DIV0 DIV1 DIV2 SPREAD CHOLD1 CHOLD2 CHOLD3 CHOLD4
LT4180
IN
4.94
4.93
4.92
4.91
–
DRAIN
COMP
R
OSC
C
OSC
VIRTUAL REMOTE SENSE
OV
RUN FB
4180 TA01a
0
0.5
1
1.5
2
2.5
3
V
(V)
WIRING
4180 TAO1b
4180fp
1