LTC3118_15 Datasheet, PDF (1/38 Pages) Linear Technology – 18V, 2A Buck-Boost DC/DC Converter with Low-Loss Dual Input PowerPath

Features
nn _{Integrated High Efficiency Dual Input PowerPath™}
Plus Buck-Boost DC/DC Converter
nn _{Ideal Diode or Priority VIN Select Modes}
nn _{VIN1 and VIN2 Range: 2.2V to 18V}
nn _{VOUT Range: 2V to 18V}
nn _{Either VIN Can Be Above, Below or Equal to VOUT}
nn _{Generates 5V at 2A for VIN > 6V}
nn _{1.2MHz Low Noise Fixed Frequency Operation}
nn _{Current Mode Control}
nn _{All Internal N-Channel MOSFETs}
nn _{Pin-Selectable PWM or Burst Mode}^® _Operation
nn _{Accurate, Independent RUN Pin Thresholds}
nn _{Up to 94% Efficiency}
nn _{VIN and VOUT Power Good Indicators}
nn _{IQ of 50µA in Sleep, 2µA in Shutdown}
nn _{4mm × 5mm 24-Lead QFN or 28-Lead TSSOP Packages}
Applications
nn _{Systems with Multiple Input Sources}
nn _{Back Up Power Systems}
nn _{Wall Adapter or Li-Ion(s) Input to 5VOUT}
nn _{Battery or Super Capacitor Input for Reserve Power}
nn _{Replace Diode-OR Designs with Higher Efficiency,}
Flexibility and Performance
LTC3118
18V, 2A Buck-Boost DC/DC
Converter with Low-Loss
Dual Input PowerPath
Description
The LTC^®3118 is a dual-input, wide voltage range syn-
chronous buck-boost DC/DC converter with an intelligent,
integrated, low-loss PowerPath control. The unique power
switch architecture provides efficient operation from either
input source to a programmable output voltage above,
below or equal to the input. Voltage capability of up to 18V
provides flexibility and voltage margin for a wide variety
of applications and power sources.
The LTC3118 uses a low noise, current mode architecture
with a fixed 1.2MHz PWM mode frequency that minimizes
the solution footprint. For high efficiency at light loads,
automatic Burst Mode operation can be selected consum-
ing only 50µA of quiescent current in sleep.
System level features include ideal diode or V_IN priority
modes, V_IN and V_OUT power good indicators, accurate RUN
comparators to program independent UVLO thresholds,
and output disconnect in shutdown. Other features include
2µA shutdown current, short-circuit protection, soft-start,
current limit and thermal overload protection.
The LTC3118 is offered in thermally enhanced 24-lead
4mm × 5mm QFN and 28-lead TSSOP packages.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners. Protected by U.S. Patents, including 7709976.
Typical Application
3.3µH
0.1µF
0.1µF
V_IN1
22µF ^{47nF VIN1 BST1 SW1}
SW2 BST2 V_OUT
400k
CM1
FB
22pF
CP1
10nF
CN1
CN2
10nF
LTC3118
100k
1.8nF
40.2k
VC
CP2
V1GD
V_IN2
V_IN2
22µF
V2GD
PGD
MODE
INDICATORS
CM2
47nF
PGND V_CC GND
SEL
RUN1
RUN2
CONTROL
SIGNALS
4.7µF
3118 TA01a
V_OUT
5V
100µF
5V_OUT
AC-COUPLED
500mV/DIV
Input Switchover Response
V_IN1 = 5V, V_IN2 = 12V, V_OUT = 5V AT 1A
SW1
10V/DIV
SEL
5V/DIV ^{SELECT V}IN2
SELECT V_IN1
100µs/DIV
3118 TA01b
3118f
For more information www.linear.com/LTC3118
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