LT3508 - Dual Monolithic 1.4A Step-Down Switching Regulator

The LT3508 is a dual current mode PWM step-down DC/DC converter with internal power switches capable of generating two 1.4A outputs. The wide input voltage range of 3.7V to 36V makes the LT3508 suitable for regulating power from a wide variety of sources, including automotive batteries, 24V industrial supplies and unregulated wall adapters. Both converters are synchronized to a single oscillator programmable up to 2.5MHz and run with opposite phases, reducing input ripple current. Its high operating frequency allows the use of small, low cost inductors and ceramic capacitors, resulting in low, predictable output ripple. Each regulator has independent tracking and softstart circuits and generates a power good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.

Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protection against shorted outputs, and soft-start eliminates input current surge during startup. The low current (<2µA) shutdown mode enables easy power management in battery-powered systems.

Features
  • Wide Input Voltage Range: 3.7V to 36V
  • Two 1.4A Output Switching Regulators with Internal Power Switches
  • Adjustable 250kHz to 2.5MHz Switching Frequency
  • Synchronizable over the Full Frequency Range
  • Anti-Phase Switching Reduces Ripple
  • Uses Small Inductors and Ceramic Capacitors
  • Accurate Programmable Undervoltage Lockout
  • Independent Tracking, Soft-Start and Power Good Circuits Ease Supply Sequencing
  • Output Adjustable Down to 800mV
  • Small 4mm × 4mm 24-Pin QFN or 16-Pin Thermally Enhanced TSSOP Surface Mount Packages
Typical Application
LT3508 Typical Application
LT3508 Typical Application
Applications
  • Automotive
  • DSP Power Supplies
  • Wall Transformer Regulation
  • DSL and Cable Modems
  • PCI Express
Packaging
LT3508 Package Drawing
LT3508 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT3508EFE#PBFTSSOP-16E$5.00$3.50
LT3508EFE#TRPBFTSSOP-16E$3.56
LT3508EUF#PBF4x4 QFN-24E$4.79$3.35
LT3508EUF#TRPBF4x4 QFN-24E$3.41
LT3508HFE#PBFTSSOP-16H$6.36$4.45
LT3508HFE#TRPBFTSSOP-16H$4.51
LT3508HUF#PBF4x4 QFN-24H$6.10$4.27
LT3508HUF#TRPBF4x4 QFN-24H$4.33
LT3508IFE#PBFTSSOP-16I$6.00$4.20
LT3508IFE#TRPBFTSSOP-16I$4.26
LT3508IUF#PBF4x4 QFN-24I$5.74$4.02
LT3508IUF#TRPBF4x4 QFN-24I$4.08
Demo Boards
Part NumberDescriptionPrice
DC1060ALT3508EFE/LT3508EUF Demo Board$125.00
Datasheet
Reliability Data
LT Journal
Press Release
CAD Symbol
Ad
LTspice
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LT3508 - Dual Monolithic 1.4A Step-Down Switching Regulator
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LT3508 Footprints and Symbols
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LT3508 Demo Circuit - Dual Monolithic 1.4A Step-Down Switching Regulator (12V to 3.3V @ 1.4A & 5V @ 1.4A)