LTC3862 Datasheet, PDF (1/40 Pages) Linear Technology – Multi-Phase Current Mode Step-Up DC/DC Controller

FEATURES
n _{Wide VIN Range: 4V to 36V Operation}
n _{2-Phase Operation Reduces Input and Output}
Capacitance
n _{Fixed Frequency, Peak Current Mode Control}
n _{5V Gate Drive for Logic-Level MOSFETs}
n _{Adjustable Slope Compensation Gain}
n _{Adjustable Max Duty Cycle (Up to 96%)}
n _{Adjustable Leading Edge Blanking}
n _{±1% Internal Voltage Reference}
n _{Programmable Operating Frequency with One}
External Resistor (75kHz to 500kHz)
n _{Phase-Lockable Fixed Frequency 50kHz to 650kHz}
n _{SYNC Input and CLKOUT for 2-, 3-, 4-, 6- or}
12-Phase Operation (PHASEMODE Programmable)
n _{Internal 5V LDO Regulator}
n _{24-Lead Narrow SSOP Package}
n _{5mm × 5mm QFN with 0.65mm Lead Pitch and}
24-Lead Thermally Enhanced TSSOP Packages
APPLICATIONS
n _{Automotive, Telecom and Industrial Power Supplies}
LTC3862
Multi-Phase Current Mode
Step-Up DC/DC Controller
DESCRIPTION
The LTC^®3862 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 5V
gate drive is optimized for most automotive and industrial
grade power MOSFETs.
Adjustable slope compensation gain allows the user to fine-
tune the current loop gain, improving noise immunity.
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. 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.
Other features include an internal 5V LDO with undervoltage
lockout protection for the gate drivers, a precision RUN
pin threshold with programmable hysteresis, soft-start
and programmable leading edge blanking and maximum
duty cycle
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
84.5k
24.9k
V_IN
RUN
GATE1
INTV_CC SENSE1⁺
4.7μF
LTC3862
66.5k
10nF _10k
10nF
BLANK
FREQ
SYNC
PLLFLTR
SENSE1^–
GATE2
SENSE2⁺
1nF
SS
SENSE2^–
3V8
PGND
CLKOUT
10nF
FB
SLOPE
D_MAX
ITH PHASEMODE
475k
12.4k 68.1k
100pF
SGND
19.4μH 19.4μH
220μF
0.006Ω _50V
22μF
50V
V_IN
5V TO 36V
V_OUT
48V
5A (MAX)
0.006Ω
3862 TA01
Efficiency vs Output Current
98
V_OUT = 48V
96
V_IN = 12V
94
92
90
V_IN = 24V
88
V_IN = 5V
86
84
82
80
100
1000
LOAD CURRENT (mA)
10000
3862 TA01b
3862fb
1