Vishay Intertechnology Inc. (Santa Clara, CA) introduced the new Siliconix Si91842 and Si91844 150mA low-noise LDO regulators, which exhibit low dropout and ground current in a compact package. They are intended for use in battery-powered systems, including cell phones, wireless handsets and modems, PDAs, notebooks, pagers, and digital cameras.
Available in a range of 14 fixed output-voltage options from 1.8V to 5V, the regulators are designed to maintain regulation while delivering 300mA peak output current in applications with high surge currents at turn-on. Targeted at low-voltage, battery-operated systems, both devices feature a low ground current of only 110µA at 150mA, as well as a low dropout voltage of only 130mV, enabling extended battery life in portable devices. The output voltage is monitored; an error flag signal is provided when the output is within five percent of nominal.
The regulators also feature a 1.5-percent guaranteed output-voltage accuracy, a fast turn-on time of 50µs (maximum) and a fast transient response of 30µs. A built-in active pull-down clamp circuit improves transient response and regulation by actively sinking current from the output if it exceeds the desired regulation voltage. The Si91842 discharges the output during shutdown mode through a 100-ohm n-channel MOSFET, while the Si91844 maintains an open circuit on the output.
