LTC3862-2
Multi-Phase Current Mode
Step-Up DC/DC Controller
FeaTures
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DescripTion
The LTC
®
3862-2 is a two-phase constant frequency, current
mode boost and SEPIC controller that drives N-channel
power MOSFETs. Two-phase operation reduces system
filtering capacitance and inductance requirements.
The operating frequency can be set with an external resistor
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.
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.
PART NUMBER
LTC3862
LTC3862-1
LTC3862-2
INTV
CC
5V
10V
10V
UV
+
3.3V
7.5V
4.4V
UV
–
2.9V
7.0V
3.9V
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Wide V
IN
Range: 5.5V to 36V Operation
2-Phase Operation Reduces Input and Output
Capacitance
Fixed Frequency, Peak Current Mode Control
Internal 10V LDO Regulator
Lower UVLO Thresholds Allows the Use of
MOSFETs Rated at 6V V
GS
Adjustable Slope Compensation Gain
Adjustable Max Duty Cycle (Up to 96%)
Adjustable Leading Edge Blanking
±1% Internal Voltage Reference
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
5mm
×
5mm QFN Package with 0.65mm Lead Pitch
24-Lead Thermally Enhanced TSSOP Package
applicaTions
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Automotive, Telecom and Industrial Power Supplies
L,
LT, LTC, LTM, Linear Technology, the Linear logo and PolyPhase are registered trademarks
and No R
SENSE
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.
Typical applicaTion
100k
24.9k
V
IN
16µH
16µH
22µF
50V
V
IN
6V TO 32V
V
OUT
80V
7A (MAX)
210µF
100V
Efficiency vs Output Current
97 V
OUT
= 80V
95
93
91
89
87
85
83
81
79
77
10
100
1000
LOAD CURRENT (mA)
V
IN
= 6V
V
IN
= 9V
V
IN
= 12V
V
IN
= 24V
10000
38622 TA01b
RUN
INTV
CC
GATE1
SENSE1
+
0.0033
4.7µF
110k
LTC3862-2
BLANK
SENSE1
–
FREQ
GATE2
SYNC
SENSE2
+
PLLFLTR
0.1µF
1nF
0.0033
SS
3V8
FB
ITH
SENSE2
–
PGND
CLKOUT
SLOPE
D
MAX
PHASEMODE
SGND
10nF
796k
12.4k
12.1k
220pF
38622 TA01a
EFFICIENCY (%)
38622f
1
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
