Santa Clara, Calif. - Siliconix Inc. has packaged a pair of 300-milliamp low-noise, low-dropout (LDO) regulators in 3 x 3-mm PowerPAK MLP33s. A low ground current suits the Si91871 and Si91872 for low-voltage, battery-operated power systems, the company said, while a dropout voltage of 250 mV at 300 mA prolongs battery life.
Tailored for use in equipment such as cell phones, wireless handsets and modems, PDAs, notebooks and digital cameras, the ICs are small enough to fit on tiny circuit boards yet handle up to 1.2 watts of power dissipation, the company said.
Designed to maintain regulation while delivering 400-mA peak output current in applications with high surge currents at turn-on, the Si91871 and Si91872 are available in a range of 14 fixed output-voltage options from 1.2 V to 5 V. Both devices feature 1.5 percent guaranteed output-voltage accuracy, a startup time of 60 microseconds and a transient response of plus/minus 30 microseconds. 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.
Both devices discharge the output during shutdown mode through a 100-ohm n-channel MOSFET. Integrated short-circuit and thermal protection ensures reliable operation, Siliconix said. Reverse battery protection limits reverse-current flow to a 1-microamps maximum shutdown current. When no output is required, digital circuitry shuts off the device to save power.
The Si91871 is especially suited for sensitive RF receiver or audio amplifier environments, the company said. It is equipped with an external noise bypass capacitor that reduces output noise to 30 microvolts (rms). The Si91872 provides an out-of-regulation error flag.
The pair may be used with low-ESR ceramic capacitors or tantalum capacitors, giving designers a flexible choice of magnetic components. Samples and production quantities are available now for most voltage options, with lead times of eight to 10 weeks for larger orders. In lots of 100,000, pricing for U.S. delivery is 28 cents apiece. Data sheets can be found on the Web site of parent Vishay Intertechnology.
Call (619) 336-0860