Datasheet LT1072

LT1072 1.25A High Efficiency Switching Regulator
U FEATURES DESCRIPTIO
■ Available in MiniDiP, TO-220, and TO-3 Packages The LT®1072 is a monolithic high power switching ■ Wide Input Voltage Range 3V to 60V regulator. It can be operated in all standard switching ■ Low Quiescent Current—6mA configurations including buck, boost, flyback, forward, ■ Internal 1.25A Switch inverting and “Cuk”. A high current, high efficiency switch ■ Very Few External Parts Required is included on the die along with all oscillator, control, and ■ Self-Protected Against Overloads protection circuitry. Integration of all functions allows the ■ Operates in Nearly All Switching Topologies LT1072 to be built in a standard 5-pin TO-3 or TO-220 ■ Shutdown Mode Draws Only 50µA Supply Current power package as well as the 8-pin miniDlP. This makes it ■ Flyback-Regulated Mode has Fully Floating Outputs extremely easy to use and provides “bust proof” operation ■ Can be Externally Synchronized similar to that obtained with 3-pin linear regulators.
U
The LT1072 operates with supply voltages from 3V to 60V,
APPLICATIO S
and draws only 6mA quiescent current. It can deliver load ■ power up to 20 watts with no external power devices. By Logic Supply 5V at 2.5A ■ utilizing current-mode switching techniques, it provides 5V Logic to ±15V Op Amp Supply ■ excellent AC and DC load and line regulation. Offline Converter up to 50W ■ Battery Upconverter The LT1072 has many unique features not found even on ■ Power lnverter (+ to –) or (– to +) the vastly more difficult to use low power control chips ■ Fully Floating Multiple Outputs presently available. It uses an adaptive anti-sat switch ■ Driver for High Current Supplies drive to allow very wide ranging load currents with no loss in efficiency. An externally activated shutdown mode
USER NOTE:
This data sheet is only intended to provide specifications, graphs, and a general functional reduces total supply current to 50µA typical for standby description of the LT1072. Application circuits are included to show the capability of the LT1072. operation. Totally isolated and regulated outputs can be A complete design manual (AN-19) should be obtained to assist in developing new designs. This manual contains a comprehensive discussion of both the LT1070 and the external components used generated by using the optional “flyback regulation mode” with it, as well as complete formulas for calculating the values of these components. The manual can also be used for the LT1072 by factoring in the lower switch current rating. built into the LT1072, without the need for optocouplers or , LTC and LT are registered trademarks of Linear Technology Corporation. extra transformer windings.
U TYPICAL APPLICATIO Boost Converter (5V to 12V) Maximum Output Power*
5V 25 220µH** V 20 IN VSW BUCK-BOOST VO = 30V LT1072 12V, 0.25A 15 + C3 10.7k FLYBACK 25µF* – BOOST GND V FB POWER (W) 10 C + ISOLATED 470µF 1k – 1.24k 5 + BUCK-BOOST 1µF – VO = 5V 0 *REQUIRED IF INPUT LEADS ≥ 2” 0 10 20 30 40 50 **PULSE ENGINEERING 52626 LT1072 • TA01 INPUT VOLTAGE (V) *ROUGH GUIDE ONLY. BUCK MODE POUT = 1A x VOUT. MINIDIP OUTPUT POWER MAY BE LIMITED BY PACKAGE TEMPERATURE RISE AT HIGH INPUT VOLTAGES OR HIGH DUTY CYCLES LT1072 • TA02 1072fc 1