LT1072 1.25A High Efficiency Switching Regulator 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 Current6mA 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 50A 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: reduces total supply current to 50A typical for standby This data sheet is only intended to provide specifications, graphs, and a general functional 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. TYPICAL APPLICATIO Boost Converter (5V to 12V) Maximum Output Power* 25 5V 220H** 20 V IN V SW BUCK-BOOST V = 30V O 15 12V, 0.25A LT1072 + C3 10.7k FLYBACK BOOST 25F* 10 FB GND V C ISOLATED + 470F 1k 1.24k 5 + BUCK-BOOST 1F V = 5V O 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 P = 1A x V . OUT OUT MINIDIP OUTPUT POWER MAY BE LIMITED BY PACKAGE TEMPERATURE RISE AT HIGH INPUT VOLTAGES OR HIGH DUTY CYCLES LT1072 TA02 1072fc 1 POWER (W) U ULT1072 ABSOLUTE AXI U RATI GS (Note 1) Note 1: Minimum switch on time for the LT1072 in current limit is Supply Voltage 0.7sec. This limits the maximum input voltage during short-circuit conditions, in the buck and inverting modes only, to 40V. Normal LT1072HV (See Note 1) ......................................... 60V (unshorted) conditions are not affected. If the LT1072 is being operated in LT1072 (See Note 1) ............................................. 40V the buck or inverting mode at high input voltages and short-circuit Switch Output Voltage conditions are expected, a resistor must be placed in series with the inductor, as follows: LT1072HV ............................................................. 75V The value of the resistor is given by: LT1072 .................................................................. 65V LT1072S8 .............................................................. 60V (t) (f) (V ) V IN f R = R L I Feedback Pin Voltage (Transient, 1ms) ................. 15V (LIMIT) Operating Junction Temperature Range t = Minimum on time of LT1072 in current limit, 0.7s LT1072HVM, LT1072M (OBSOLETE) .... 55C to 150C f = Operating frequency (40kHz) V = Forward voltage of external catch diode at I LT1072HVC, LT1072C (Oper.)*............0C to 100C f (LIMIT) I = Current limit of LT1072 (2A) (LIMIT) LT1072HVC, LT1072C (Sh. Ckt.)* ........0C to 125C R = Internal series resistance of inductor L LT1072HVI ....................................... 40C to 125C Storage Temperature Range............... 65C to 150C Lead Temperature (Soldering, 10 sec)...............300C *Includes LT1072S8 UUW PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART NUMBER NUMBER TOP VIEW TOP VIEW BOTTOM VIEW V V GND 1 E2 GND 1 8 E2 SW C 8 LT1072HVMK LT1072CN8 V 2 7 V V 2 7 V C SW C SW 1 2 CASE IS 3 6 3 6 FB E1 FB E1 3 LT1072MK LT1072CS8 GND 4 NC 4 5 4 5 V NC V IN IN LT1072HVCK V FB IN S8 PART S8 PACKAGE N PACKAGE K PACKAGE LT1072CK 8-LEAD PLASTIC SO 8-LEAD PDIP 4-LEAD TO-3 METAL CAN MARKING T = 100C, = 130C/W T = 100C, = 130C/W JMAX JA JMAX JA T = 150C, = 8C/W, = 35C/W JMAX JC JA T = 100C*, = 8C/W, = 35C/W JMAX JC JA 1072 J PACKAGE LT1072MJ8 8-LEAD CERAMIC DIP T = 150C, = 100C/W LT1072CJ8 JMAX JA OBSOLETE PACKAGE OBSOLETE PACKAGE Consider the S8 or N8 Packages for Alternate Source TOP VIEW ORDER PART ORDER PART FRONT VIEW NUMBER NUMBER NC 1 16 NC NC 2 15 NC 5 V IN 4 V LT1072CT 3 14 GND E2 LT1072CSW SW 3 GND V 4 13 V C SW LT1072HVCT 2 FB 5 12 FB E1 1 V C LT1072HVIT 6 11 NC V IN T PACKAGE 7 10 NC NC 5-LEAD TO-220 8 9 NC NC T = 100C/W, = 8C/W, = 50C/W JMAX JC JA SW PACKAGE 16-LEAD PLASTIC SO WIDE T = 100C, = 130C/W JMAX JC LT1072 POI01 Consult LTC Marketing for parts specified with wider operating temperature ranges. 1072fc 2 U WWW