LT1185 Low Dropout Regulator FEATURES ■ Low Resistance Pass Transistor: 0.25 Ω The LT1185 uses a saturation-limited NPN transistor as ■ Dropout Voltage: 0.75V at 3A the pass element. This device gives the linear dropout ■ ± 1% Reference Voltage characteristics of a FET pass element with significantly ■ AccurateProgrammable Current Limit less die area. High efficiency is maintained by using special ■ Shutdown Capability anti-saturation circuitry that adjusts base drive to track ■ Internal Reference Available load current. The “on resistance” is typically 0.25Ω. ■ 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 U when the program current is less than 1 DESCRIPTIO µA, allowing 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. the internal reference voltage. All other trademarks are the property of their respective owners. UTYPICAL APPLICATIO5V, 3A Regulator with 3.5A Current LimitDropout Voltage + + 1.6 + 2µF RLIM* 2.37k 1.4 TANT 4.3k V 1.2 IN 6V TO 16V REF GND + V 2µF OUT 1.0 FB 5V AT 3A (V) TANT TJ = 25°C OUT 0.8 T – – V J = 125°C V 2.67k IN LT1185 INV 0.6 V 0.4 OUT – LT1185 • TA01 TJ = –55°C 0.2 *CURRENT LIMIT = 15k/RLIM = 3.5A 0 0 1 2 3 4 LOAD CURRENT (A) LT1185 • TA02 1185ff 1