LT1185 Low Dropout Regulator FEATURES The LT1185 uses a saturation-limited NPN transistor as Low Resistance Pass Transistor: 0.25 Dropout Voltage: 0.75V at 3A the pass element. This device gives the linear dropout characteristics of a FET pass element with significantly 1% Reference Voltage less die area. High efficiency is maintained by using special Accurate Programmable Current Limit Shutdown Capability anti-saturation circuitry that adjusts base drive to track load current. The on resistance is typically 0.25. Internal Reference Available Full Remote Sense Accurate current limit is programmed with a single 1/8W Low Quiescent Current: 2.5mA external resistor, with a range of zero to three amperes. A Good High Frequency Ripple Rejection second, fixed internal limit circuit prevents destructive Available in 5-Lead TO-220 and DD Packages currents if the programming current is accidentally over- ranged. Shutdown of the regulator output is guaranteed when the program current is less than 1A, allowing DESCRIPTIO external logic control of output voltage. The LT 1185 is a 3A low dropout regulator with adjustable The LT1185 has all the protection features of previous current limit and remote sense capability. It can be used as LTC regulators, including power limiting and thermal a positive output regulator with floating input or as a shutdown. standard negative regulator with grounded input. The output voltage range is 2.5V to 25V, with 1% accuracy on , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. the internal reference voltage. TYPICAL APPLICATIO 5V, 3A Regulator with 3.5A Current Limit Dropout Voltage 1.6 + + + 2F R * 1.4 LIM 2.37k TANT 4.3k 1.2 V IN 6V TO 16V REF GND + V OUT 1.0 2F FB 5V AT 3A T = 25C TANT J 0.8 T = 125C J V LT1185 2.67k IN 0.6 0.4 V OUT LT1185 TA01 T = 55C J 0.2 *CURRENT LIMIT = 15k/R = 3.5A 0 LIM 0 1 2 3 4 LOAD CURRENT (A) LT1185 TA02 1185ff 1 V V (V) IN OUT U ULT1185 (Note 1) ABSOLUTE AXI U RATI GS Input Voltage .......................................................... 35V Operating Junction Temperature Range* Input-Output Differential ......................................... 30V Control Section FB Voltage ................................................................ 7V LT1185C ............................................. 0C to 125C REF Voltage .............................................................. 7V LT1185I .......................................... 40C to 125C Output Voltage ........................................................ 30V LT1185M (OBSOLETE) ................... 55C to 150C Output Reverse Voltage ............................................ 2V Power Transistor Section Operating Ambient Temperature Range LT1185C ............................................. 0C to 150C LT1185C ............................................... 0C to 70C LT1185I .......................................... 40C to 150C LT1185I ............................................. 40C to 85C LT1185M (OBSOLETE) ................... 55C to 175C LT1185M (OBSOLETE) .................... 55C to 125C Storage Temperature Range ................ 65C to 150C Lead Temperature (Soldering, 10 sec)................ 300C *See Application Section for details on calculating Operation Junction Temperature UUW PACKAGE/ORDER I FOR ATIO BOTTOM VIEW GND FB FRONT VIEW FRONT VIEW 5 REF 5 REF 1 2 4 V OUT 4 V OUT TAB V (CASE) IN IS 3 V IN 3 V IN 3 4 V IN 2 FB 2 FB 1 GND 1 GND V OUT REF Q PACKAGE TAB IS V T PACKAGE IN K PACKAGE 5-LEAD PLASTIC DD 5-LEAD PLASTIC TO-220 4-LEAD TO-3 METAL CAN = 2.5C/W, = 35C/W T = 150C, = 30C/W JC MAX JA = 2.5C/W, = 50C/W JMAX JA JC MAX JA OBSOLETE PACKAGE ORDER PART ORDER PART LT1185CQ ORDER PART LT1185CT LT1185MK NUMBER NUMBER LT1185IQ NUMBER LT1185IT Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: