LTC3862-2
Multi-Phase Current Mode
Step-Up DC/DC Controller
FeaTures
DescripTion
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Wide V Range: 5.5V to 36V Operation
TheLTC®3862-2isatwo-phaseconstantfrequency,current
mode boost and SEPIC controller that drives N-channel
power MOSFETs. Two-phase operation reduces system
filtering capacitance and inductance requirements.
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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Internal 10V LDO Regulator
Theoperatingfrequencycanbesetwithanexternalresistor
over a 75kHz to 500kHz range and can be synchronized
to an external clock using the internal PLL. Multiphase
operation is possible using the SYNC input, the CLKOUT
output and the PHASEMODE control pin allowing 2-, 3-,
4-, 6- or 12-phase operation.
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Lower UVLO Thresholds Allows the Use of
MOSFETs Rated at 6V V
GS
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Adjustable Slope Compensation Gain
Adjustable Max Duty Cycle (Up to 96%)
Adjustable Leading Edge Blanking
1ꢀ Internal Voltage Reference
Other features include an internal 10V LDO with under-
voltage lockout protection for the gate drivers, a preci-
sion RUN pin threshold with programmable hysteresis,
soft-start and programmable leading edge blanking and
maximum duty cycle.
Programmable Operating Frequency with One
External Resistor (75kHz to 500kHz)
Phase-Lockable Fixed Frequency 50kHz to 650kHz
SYNC Input and CLKOUT for 2-, 3-, 4-, 6- or
12-Phase Operation (PHASEMODE Programmable)
24-Lead Narrow SSOP Package
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PART NUMBER
LTC3862
INTV
UV
UV
CC
5mm × 5mm QFN Package with 0.65mm Lead Pitch
24-Lead Thermally Enhanced TSSOP Package
5V
3.3V
7.5V
4.4V
2.9V
7.0V
3.9V
LTC3862-1
LTC3862-2
10V
10V
applicaTions
L, LT, LTC, LTM, Linear Technology, the Linear logo and PolyPhase are registered trademarks
and No R and ThinSOT are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents, including
6144194, 6498466, 6611131.
SENSE
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Automotive, Telecom and Industrial Power Supplies
Typical applicaTion
V
IN
6V TO 32V
22µF
50V
Efficiency vs Output Current
100k
16µH
16µH
V
OUT
V
= 80V
97
95
93
91
89
87
85
83
81
79
77
OUT
80V
V
24.9k
IN
7A (MAX)
RUN
INTV
GATE1
+
SENSE1
CC
210µF
100V
4.7µF
0.0033Ω
LTC3862-2
–
BLANK
FREQ
SYNC
SENSE1
110k
GATE2
+
SENSE2
PLLFLTR
0.1µF
V
V
V
V
= 6V
IN
IN
IN
IN
0.0033Ω
= 9V
SS
–
= 12V
= 24V
SENSE2
1nF
3V8
PGND
CLKOUT
SLOPE
10
100
1000
10000
FB
LOAD CURRENT (mA)
10nF
D
MAX
38622 TA01b
ITH
PHASEMODE
SGND
12.1k
796k
12.4k
220pF
38622 TA01a
38622f
1