n Wide Input Voltage Range: 3V to 40V
n Single Feedback Pin for Positive or Negative
n Internal 5A/40V Power Switch
n Current Mode Control Provides Excellent Transient
n Programmable Operating Frequency (100kHz to
1MHz) with One External Resistor
n Synchronizable to an External Clock
n Low Shutdown Current < 1μA
n Internal 5.2V Low Dropout Voltage Regulator
n Programmable Input Undervoltage Lockout with
n Programmable Soft-Start
n Thermally Enhanced QFN (5mm × 6mm) Package
Boost, Flyback, SEPIC and
with 5A, 40V Switch
The LT®3957 is a wide input range, current mode DC/DC
converter which is capable of generating either positive
or negative output voltages. It can be conﬁgured as either
a boost, ﬂyback, SEPIC or inverting converter. It features
an internal low side N-channel power MOSFET rated for
40V at 5A and driven from an internal regulated 5.2V
supply. The ﬁxed frequency, current-mode architecture
results in stable operation over a wide range of supply
and output voltages.
The operating frequency of LT3957 can be set with an
external resistor over a 100kHz to 1MHz range, and can
be synchronized to an external clock using the SYNC pin.
A minimum operating supply voltage of 3V, and a low
shutdown quiescent current of less than 1μA, make the
LT3957 ideally suited for battery-powered systems.
The LT3957 features soft-start and frequency foldback
functions to limit inductor current during start-up.
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. Patents pending.
4.5V TO 16V
High Efﬁciency Output Boost Converter
Efﬁciency vs Output Current
VIN = 12V
100 200 300 400 500 600
OUTPUT CURRENT (mA)
Free Datasheet http://www.datasheet4u.com/