LT1185

The LT1185 is a 3A low dropout regulator with adjustable current limit and remote sense capability. It can be used as a positive output regulator with floating input or as a standard negative regulator with grounded input. The output voltage range is 2.5V to 25V, with ±1% accuracy on the internal reference voltage.

The LT1185 uses a saturation-limited NPN transistor as the pass element. This device gives the linear dropout characteristics of a FET pass element with significantly less die area. High efficiency is maintained by using special anti-saturation circuitry that adjusts base drive to track load current. The “on resistance” is typically 0.25Ω.

Accurate current limit is programmed with a single 1/8W external resistor, with a range of zero to three amperes. A second, fixed internal limit circuit prevents destructive currents if the programming current is accidentally over-ranged. Shutdown of the regulator output is guaranteed when the program current is less than 1µA, allowing external logic control of output voltage.

The LT1185 has all the protection features of our previous regulators, including power limiting and thermal shutdown.