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LT1959: 4.5A, 500kHz Step-Down Switching Regulator Data Sheet8/27/2007PDF297K
Overview
Features and Benefits
- 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: 0.07Ω
- Shutdown Current: 20µA
- Easily Synchronizable
- Cycle-by-Cycle Current Limiting
- 4.5A Switch
- Current Mode Control
Product Details
The LT1959 is a 500kHz monolithic buck mode switching regulator functionally identical to the LT1506 but optimized for lower output voltage applications. It will operate down to 1.21V output compared to 2.42V for the LT1506. A 4.5A switch is included on the die along with all the necessary oscillator, control and logic circuitry. High switching frequency allows a considerable reduction in the size of external components. The topology is current mode for fast transient response and good loop stability.
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.
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
Product Categories
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Documentation & Resources
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R386 Reliability Data3/22/2018PDF139 K
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DC355A - Demo Manual9/24/2009PDF329K
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DC356A - Demo Manual9/24/2009PDF329K
Tools & Simulations
LTspice
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Models for the following parts are available in LTspice:
LT1959
Reference Designs (2)
Design Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
| Part Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
|---|---|---|---|---|
| LT1959CR#PBF | Material Declaration | Reliability Data | 7-Lead DD Pak | |
| LT1959CR#TRPBF | Material Declaration | Reliability Data | 7-Lead DD Pak | |
| LT1959CS8#PBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| LT1959CS8#TRPBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| LT1959IR#PBF | Material Declaration | Reliability Data | 7-Lead DD Pak | |
| LT1959IR#TRPBF | Material Declaration | Reliability Data | 7-Lead DD Pak | |
| LT1959IS8#PBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| LT1959IS8#TRPBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| Wafer Fabrication Data | R386 Reliability Data |
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.