LTC3862-1
Multi-Phase Current Mode
Step-Up DC/DC Controller
DESCRIPTION
FEATURES
TheLTC®3862-1isatwophaseconstantfrequency,current
mode boost and SEPIC controller that drives N-channel
power MOSFETs. Two phase operation reduces system
filteringcapacitanceandinductancerequirements.The10V
gate drive is optimized for most automotive and industrial
grade power MOSFETs.
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Wide V Range: 8.5V to 36V Operation
IN
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2-Phase Operation Reduces Input and Output
Capacitance
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Fixed Frequency, Peak Current Mode Control
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10V Gate Drive for High Voltage MOSFETs
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Adjustable Slope Compensation Gain
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Adjustable Max Duty Cycle (Up to 96%)
Adjustableslopecompensationgainallowstheusertofine-
tune the current loop gain, improving noise immunity.
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Adjustable Leading Edge Blanking
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1ꢀ Internal Voltage Reference
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Theoperatingfrequencycanbesetwithanexternalresistor
over a 75kHz to 500kHz range and can be synchronized
to an external clock using the internal PLL. Multi-phase
operation is possible using the SYNC input, the CLKOUT
output and the PHASEMODE control pin allowing 2-, 3-,
4-, 6- or 12-phase operation.
Programmable Operating Frequency with One
External Resistor (75kHz to 500kHz)
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Phase-Lockable Fixed Frequency 50kHz to 650kHz
SYNC Input and CLKOUT for 2-, 3-, 4-, 6- or
12-Phase Operation (PHASEMODE Programmable)
Internal 10V LDO Regulator
24-Lead Narrow SSOP Package
5mm × 5mm QFN Package with 0.65mm Lead Pitch
24-Lead Thermally Enhanced TSSOP Package
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Other features include an internal 10V LDO with
undervoltage lockout protection for the gate drivers, a
precision RUN pin threshold with programmable hyster-
esis, soft-start and programmable leading edge blanking
and maximum duty cycle. The LTC3862 is a 5V gate drive
version of the LTC3862-1.
APPLICATIONS
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Automotive, Telecom and Industrial Power Supplies
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 6144194, 6498466, 6611131.
TYPICAL APPLICATION
V
IN
8.5V TO 36V
22μF
50V
150k
Efficiency vs Output Current
56μH
56μH
V
OUT
100
98
96
94
92
90
88
86
84
82
80
72V
V
= 72V
OUT
V
24.9k
IN
2A (MAX)
RUN
INTV
GATE1
+
V
= 32V
IN
SENSE1
CC
110μF
100V
4.7μF
V
= 24V
0.020Ω
LTC3862-1
IN
–
BLANK
FREQ
SYNC
SENSE1
45.3k
GATE2
+
SENSE2
V
= 9V
IN
PLLFLTR
0.1μF
0.020Ω
SS
–
SENSE2
1nF
3V8
PGND
CLKOUT
SLOPE
FB
100
1000
10000
1.5nF
45.3k
D
MAX
LOAD CURRENT (mA)
38621 TA01b
ITH
PHASEMODE
SGND
324k
5.62k
100pF
38621 TA01a
38621f
1