The UC1832 and UC1833 series of precision linear regulators include all control functions required in very low dropout linear regulator designs. Additionally, they feature an innovative duty proportional current limiting technique which provides peak load capability while limiting the average power dissipation of the external bypass transistor during fault conditions. When the load current reaches an accurately programmed threshold, the gated astable timer is enabled, the switching regulator qualifies the device and an externally programmable duty cycle ratio. At the time of the ON element, the output current limit is slightly higher than the trip threshold of the duty-free proportional timer. The constant current limit of the UCx832 is programmable, allowing higher peak current times on the device. With proportional control of tariffs, higher initial load requirements and short circuit protection can be accommodated without additional heat sinks or foldback current limiting. Additionally, if the TIMER pin is grounded, the proportional-responsibility timer is disabled and the IC operates in constant-voltage/constant-current regulation mode. These ICs include a 2-volt (±1%) reference, error amplifier, undervoltage lockout, and high-current source and sink output drivers, allowing the use of either NPN or PNP external pass transistors. Safe operation is guaranteed by the inclusion of undervoltage lockout (UVLO) and thermal shutdown. The UC1833 family includes the basic features of this design in a low-cost, 8-pin mini-DIP package, while the UC1832 family adds 14-pin availability for versatility. Package options include plastic (N suffix), or ceramic (J suffix). The specified operating temperature ranges are: commercial (0°C to 70°C) for UC3832/3 (N or J); industrial (-25°C to 85°C) for UC2832/3 (N or J) and military (-55°C to 125°C) for UC1832/3J. Surface mount packaging is also available.