LT1959 - 4.5A, 500kHz Step-Down Switching Regulator

A special high speed bipolar process and new design techniques achieve high efficiency at high switching frequency. Efficiency is maintained over a wide output current range by keeping quiescent supply current to 4mA and by utilizing a supply boost capacitor to saturate the power switch.

The LT1959 fits into standard 7-pin DD and fused lead SO-8 packages. Full cycle-by-cycle short-circuit protection and thermal shutdown are provided. Standard surface mount external parts are used, including the inductor and capacitors. There is the optional function of shutdown or synchronization. A shutdown signal reduces supply current to 20µA. Synchronization allows an external logic level signal to increase the internal oscillator from 580kHz to 1MHz.

Features
  • Operates with Input as Low as 4V
  • Output Range Down to 1.21V
  • Constant 500kHz Switching Frequency
  • Uses All Surface Mount Components
  • Inductor Size Reduced to 1.8µH
  • Saturating Switch Design: 0.07 Ohms
  • Shutdown Current: 20µA
  • Easily Synchronizable
  • Cycle-by-Cycle Current Limiting
  • 4.5A Switch
  • Current Mode Control
Typical Application

Applications
  • Portable Computers
  • Battery-Powered Systems
  • Battery Chargers
  • Distributed Power
  • 5V to 3.3V Conversion
  • 5V to 2.5V Conversion
  • 5V to 1.8V Conversion
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT1959CR#PBFDDPAK-7C$5.61$4.74
LT1959CR#TRPBFDDPAK-7C$4.86
LT1959CS8#PBFSO-8C$5.19$4.39
LT1959CS8#TRPBFSO-8C$4.45
LT1959IR#PBFDDPAK-7I$6.39$5.40
LT1959IR#TRPBFDDPAK-7I$5.52
LT1959IS8#PBFSO-8I$5.98$5.05
LT1959IS8#TRPBFSO-8I$5.11
Demo Boards
Part NumberDescriptionPrice
DC355ALT1959CS8 | 4.5A Switch, 500kHz Step-Down Regulator, 5V to 15Vin, 1.8Vout @ 4A$150.00
DC356ALT1959CR | 4.5A Switch, 500kHz Step-Down Regulator, 5V to 15Vin, 1.8Vout @ 4A$150.00
Datasheet
Reliability Data
Related Product
LT1959 - 4.5A, 500kHz Step-Down Switching Regulator
LT1959 - 4.5A, 500kHz Step-Down Switching Regulator
LT1959 Package Drawing LT1959
R386 Reliability Data
LT1959 Footprints and Symbols