LT3477 - 3A, DC/DC Converter with Dual Rail-to-Rail Current Sense

The LT3477 is a current mode, 3A DC/DC step-up converter 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. Efficiency 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 positive 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- current applications.

Features
  • Dual 100mV Rail-to-Rail Current Sense Amplifiers
  • Wide Input Voltage Range: 2.5V to 25V
  • 3A, 42V Internal Switch
  • High Efficiency Power Conversion: Up to 93%
  • Drives LEDs in Boost, Buck-Boost or Buck Mode
  • Frequency Set by External Resistor: 200kHz to 3.5MHz
  • Programmable Soft-Start
  • Low VCESAT Switch: 0.3V at 2.5A
  • Capable of Positive and Negative Output Voltages (Boost, Inverting, SEPIC, Flyback)
  • Available in Thermally Enhanced 20-Lead (4mm × 4mm) QFN and 20-Lead TSSOP Packages
Typical Application

Applications
  • High Power LED Driver
  • DSL Modems
  • Distributed Power
  • Input/Output Current Limited Boost, SEPIC, Inverting, Flyback Converters
  • Constant-Voltage, Constant-Current Source
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT3477EFE#PBFTSSOP-20E$4.71$3.30
LT3477EFE#TRPBFTSSOP-20E$3.42
LT3477EUF#PBF4x4 QFN-20E$4.50$3.15
LT3477EUF#TRPBF4x4 QFN-20E$3.25
LT3477IFE#PBFTSSOP-20I$5.66$3.96
LT3477IFE#TRPBFTSSOP-20I$4.02
LT3477IUF#PBF4x4 QFN-20I$5.40$3.78
LT3477IUF#TRPBF4x4 QFN-20I$3.84
Demo Boards
Part NumberDescriptionPrice
DC1130ALT3477EFE/LT3003EMSEContact Factory
DC841ALT3477EFE | Constant Current Boost LED Driver, 2.7V ≤ VIN ≤ 16V, VLED up to 36V @ 330mA$100.00
Datasheet
Design Note
Reliability Data
LT Journal
Press Release
LTspice
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