n Dual 100mV Rail-to-Rail Current Sense Ampliﬁers
n Wide Input Voltage Range: 2.5V to 25V
n 3A, 42V Internal Switch
n High Efﬁciency Power Conversion: Up to 93%
n Drives LEDs in Boost, Buck-Boost or Buck Mode
n Frequency Set by External Resistor: 200kHz to 3.5MHz
n Programmable Soft-Start
n Low VCESAT Switch: 0.3V at 2.5A
n Capable of Positive and Negative Output Voltages
(Boost, Inverting, SEPIC, Flyback)
n Available in Thermally Enhanced 20-Lead
(4mm × 4mm) QFN and 20-Lead TSSOP Packages
n High Power LED Driver
n DSL Modems
n Distributed Power
n Input/Output Current Limited Boost, SEPIC,
Inverting, Flyback Converters
n Constant-Voltage, Constant-Current Source
3A, DC/DC Converter
with Dual Rail-to-Rail
The LT®3477 is a current mode, 3A DC/DC step-up con-
verter with dual rail-to-rail current sense ampliﬁers and an
internal 3A, 42V switch. It combines a traditional voltage
feedback loop and two unique current feedback loops to
operate as a constant-current, constant-voltage source.
Both current sense voltages are set at 100mV and can be
adjusted independently using the IADJ1 and IADJ2 pins. Ef-
ﬁciency of up to 91% can be achieved in typical applications.
The LT3477 features a programmable soft-start function
to limit inductor current during start-up. Both inputs of
the error ampliﬁer are available externally allowing posi-
tive and negative output voltages (boost, inverting, SEPIC,
Flyback). The switching frequency is programmable from
200kHz to 3.5MHz through an external resistor.
Available in thermally enhanced 20-pin (4mm × 4mm)
QFN and 20-pin TSSOP packages, the LT3477 provides a
complete solution for both constant-voltage and constant-
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
330mA LED Driver With Open LED Protection
SHDN SHDN LT3477