Features and Benefits
- Wide Input Voltage Range: 3V to 60V
- Low Quiescent Current: 6mA
- Internal 5A Switch (2.5A for LT1171, 1.25A for LT1172)
- Shutdown Mode Draws Only 50μA Supply Current
- Very Few External Parts Required
- Self-Protected Against Overloads
- Operates in Nearly All Switching Topologies
- Flyback-Regulated Mode Has Fully Floating Outputs
- Comes in Standard 5-Pin Packages
- LT1172 Available in 8-Pin MiniDIP and Surface Mount Packages
- Can Be Externally Synchronized
The LT1170/LT1171/LT1172 are monolithic high power switching regulators. They can be operated in all standard switching configurations including buck, boost, flyback, forward, inverting and “Cuk.” A high current, high efficiency switch is included on the die along with all oscillator, control and protection circuitry. Integration of all functions allows the LT1170/LT1171/LT1172 to be built in a standard 5-pin TO-3 or TO-220 power package as well as the 8-pin packages (LT1172). This makes them extremely easy to use and provides “bust proof” operation similar to that obtained with 3-pin linear regulators.
The LT1170/LT1171/LT1172 operate with supply voltages from 3V to 60V, and draw only 6mA quiescent current. They can deliver load power up to 100W with no external power devices. By utilizing current-mode switching techniques, they provide excellent AC and DC load and line regulation.
The LT1170/LT1171/LT1172 have many unique features not found even on the vastly more difficult to use low power control chips presently available. They use adaptive antisat switch drive to allow very wide ranging load currents with no loss in efficiency. An externally activated shutdown mode reduces total supply current to 50μA typically for standby operation.
- Logic Supply 5V at 10A
- 5V Logic to ±15V Op Amp Supply
- Battery Upconverter
- Power Inverter (+ to –) or (– to +)
- Fully Floating Multiple Outputs
This data sheet is only intended to provide specifications, graphs, and a general functional description of the LT1170/LT1171/LT1172. Application circuits are included to show the capability of the LT1170/LT1171/LT1172. A complete design manual (AN19) should be obtained to assist in developing new designs. This manual contains a comprehensive discussion of both the LT1070 and the external components used with it, as well as complete formulas for calculating the values of these components. The manual can also be used for the LT1170/LT1171/LT1172 by factoring in the higher frequency. A CAD design program called SwitcherCAD® is also available.
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.
Documentation & Resources
R012 Reliability Data3/23/201831 K
AN118 - High Voltage, Low Noise, DC/DC Converters6/17/20152M
AN61 - Practical Circuitry for Measurement and Control Problems2/5/20131M
AN65 - A Fourth Generation of LCD Backlight Technology2/5/20135M
AN98 - Signal Sources, Conditioners and Power Circuitry Circuits of the Fall, 20049/4/2008864K
AN113 - Power Conversion, Measurement and Pulse Circuits10/15/2007675K
AN49 - Illumination Circuitry for Liquid Crystal Displays10/15/20075M
AN55 - Techniques for 92% Efficient LCD Illumination8/20/2007672K
AN51 - Power Conditioning for Notebook and Palmtop Systems8/20/2007253K
Positive-to-Negative Converter Powers –48V Telecom Circuits5/1/1998 LT Journal
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