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LTC3872_15 Datasheet, PDF (1/22 Pages) Linear Technology – No RSENSE Current Mode Boost DC/DC Controller
LTC3872
No RSENSE
Current Mode Boost
DC/DC Controller
Features
n No Current Sense Resistor Required
n VOUT up to 60V
n Constant Frequency 550kHz Operation
n Internal Soft-Start and Optional External Soft-Start
n Adjustable Current Limit
n Pulse Skipping at Light Load
n VIN Range: 2.75V to 9.8V
n ±1.5% Voltage Reference Accuracy
n Current Mode Operation for Excellent Line and Load
Transient Response
n Low Profile (1mm) SOT-23 and 2mm × 3mm DFN
Packages
Applications
n Telecom Power Supplies
n 42V Automotive Systems
n 24V Industrial Controls
n IP Phone Power Supplies
Description
The LTC®3872 is a constant frequency current mode
boost DC/DC controller that drives an N-channel power
MOSFET and requires very few external components. The
No RSENSETM architecture eliminates the need for a sense
resistor, improves efficiency and saves board space.
The LTC3872 provides excellent AC and DC load and line
regulation with ±1.5% output voltage accuracy. It incor-
porates an undervoltage lockout feature that shuts down
the device when the input voltage falls below 2.3V.
High switching frequency of 550kHz allows the use of a
small inductor. The LTC3872 is available in an 8-lead low
profile (1mm) ThinSOTTM package and 8-pin 2mm × 3mm
DFN package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No RSENSE and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
Typical Application
High Efficiency 3.3V Input, 5V Output Boost Converter
1.8nF 17.4k
ITH
VIN
47pF VIN
IPRG
LTC3872
GND
SW
VFB RUN/SS NGATE
11k
1%
1nF
34.8k
1%
1µH
D1
M1
100µF
×2
VIN
3.3V
10µF
VOUT
5V
2A
3872 TA01
Efficiency and Power Loss vs Load Current
100
90
80
70
60
50
40
30
20
10
0
1
10
1
0.1
0.01
10
100
1000
LOAD CURRENT (mA)
0.001
10000
3872 TA01b
For more information www.linear.com/LTC3872
3872fc
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