LTC3112
15V, 2.5A Synchronous
Buck-Boost DC/DC
Converter
FEATURES DESCRIPTION
n
Regulated Output with V Above, Below or Equal to V The LTC 3112 is a fixed frequency synchronous buck-boost
IN OUT
n
2.7V to 15V Input Voltage Range DC/DC converter with an extended input and output range.
n
2.5V to 14V Output Voltage Range The unique 4-switch, single inductor architecture provides
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2.5A Continuous Output Current: V 5V, low noise and seamless operation from input voltages
IN
V = 5V, PWM Mode above, below or equal to the output voltage.
OUT
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Output Current Monitor
With an input range of 2.7V to 15V, the LTC3112 is well-
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Up to 95% Efficiency
suited for a wide variety of single or multiple cell battery,
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750kHz Switching Frequency, Synchronizable
backup capacitor or wall adapter source applications. Low
Between 300kHz and 1.5MHz
R internal N-Channel MOSFET switches provide
DS(ON)
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Internal N-Channel MOSFETs
highly efficient operation in applications with higher load
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Selectable Burst Mode Operation, I = 50A
Q
current requirements.
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Shutdown Current < 1A
n The LTC3112 features selectable PWM or Burst Mode
Overvoltage Protection
n operation, an easily synchronized oscillator and output
Output Disconnect in Shutdown
n disconnect in shutdown. An output current monitor circuit
Internal Soft-Start
n allows the load current to be controlled or measured. Other
Small, Thermally Enhanced 16-Lead (4mm 5mm
features include <1A shutdown current, short circuit
0.75mm) DFN and 20-Lead TSSOP Package
protection, soft-start, current limit and thermal shutdown.
APPLICATIONS
The LTC3112 is offered in both a 16-pin (4mm 5mm
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3.3V or 5V from 1, 2 or 3 Li-Ion, Backup Capacitor Stack
0.75mm) DFN and 20-pin TSSOP packages.
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Hand Held Inventory Terminals
L, LT, LTC, LTM, Linear Technology Burst Mode, LTSpice and the Linear logo are registered
trademarks and No R and PowerPath are trademarks of Linear Technology Corporation.
n
SENSE
RF Transmitters
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
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including 5481178.
12V Synchronous Boost Converter
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Multiple Power Input Systems
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LED Lighting with Current Regulation
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12V Lead Acid Battery to 12V
TYPICAL APPLICATION
Efficiency at 5V
OUT
100
5V, 750kHz Wide Input Voltage Range Buck-Boost Regulator
PWM
90
4.7H
BURST
80
0.1F 0.1F
SW1 SW2
70
BST1 BST2
5V/2.5A, V > 5V
2.7V TO 15V IN
V V V V
IN OUT OUT
IN
33k
60
680pF 47pF
LTC3112
V COMP
CC
845k
10k
22pF
BURST PWM
PWM/SYNC
50
FB
10F
OFF ON TO ADC
RUN I
2.7V
OUT
IN
40
1V PER AMP 47F 5.0V
IN
GND OVP
12V
1F 100pF 42.2k 158k
IN
30
0.0001 0.001 0.01 0.1 1
3112 TA01
LOAD CURRENT (A)
3112 TA02
3112fd
1
For more information www.linear.com/LTC3112
EFFICIENCY (%)LTC3112
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 3)
RUN Voltage............................................... 0.3V to 16V
V Voltage ................................................. 0.3V to 16V
IN PWM/SYNC, V , I Voltage ....................0.3V to 6V
CC OUT
V Voltage .............................................. 0.3V to 15V
OUT FB, COMP, OVP Voltage ...............................0.3V to 6V
SW1 Voltage (Note 4) ................... 0.3V to (V + 0.3V)
IN Operating Junction Temperature Range (Notes 2, 6)
SW2 Voltage (Note 4) ................ 0.3V to (V + 0.3V)
OUT ............................................................... 55C to 150C
V Voltage ...................(V 0.3V) to (V + 6V)
BST1 SW1 SW1 Storage Temperature Range ..................65C to 150C
V Voltage ...................(V 0.3V) to (V + 6V)
BST2 SW2 SW2 Lead Temperature (Soldering, 10sec) TSSOP .......300C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
GND 1 GND
20
COMP 2 PWM/SYNC
COMP 1 16 PWM/SYNC 19
FB 3 V
FB 2 15 V 18
CC CC
OVP 4 BST1
OVP 3 14 BST1 17
V 5 SW1
V 4 13 SW1 16
IN IN
17 21
GND GND
V 6 SW1
V 5 12 SW1 15
IN IN
RUN 6 11 BST2 RUN 7 BST2
14
I 7 10 SW2 I 8 SW2
13
OUT OUT
V 8 9 SW2 V 9 SW2
12
OUT OUT
GND 10 GND
11
DHD16 PACKAGE
16-LEAD (5mm 4mm) PLASTIC DFN
FE PACKAGE
T =150 C, q = 43C/W, q = 4C/W 20-LEAD PLASTIC TSSOP
JMAX JA JC
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
T = 150C, q = 38C/W, q = 4C/W
JMAX JA JC
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION