1 Features

1• 2.5-V to 6-V Input Range

• 300-mA Output Current

• 60-dB PSRR at 1 kHz

• ≤ 1-μA Quiescent Current When Shut Down

• Fast Turnon Time: 120 μs (typical) with CBYPASS =

0.01 μF

• 132-mV Typical Dropout with 300-mA Load

• 35-μVrms Output Noise Over 10 Hz to 100 kHz

• Logic Controlled Enable

• Stable With Ceramic and High-Quality Tantalum

Capacitors

• Thermal Shutdown and Short-Circuit Current Limit

• Low Thermal Resistance in WSON-6 Package

Gives Excellent Power Capability

2 Applications

• CDMA Cellular Handsets

• Wideband CDMA Cellular Handsets

• GSM Cellular Handsets

• Portable Information Appliances

3 Description

Performance of the LP3981 device is optimized for

battery-powered systems to deliver ultra-low-noise, extremely low dropout voltage, and low quiescent

current. Regulator ground current increases only

slightly in dropout, further prolonging the battery life.

Power supply rejection is better than 60 dB at low

frequencies. This high power supply rejection is

maintained down to lower input voltage levels

common to battery-operated circuits.

The device is ideal for mobile phone and similar

battery-powered wireless applications. It provides up

to 300 mA, from a 2.5-V to 6-V input, consuming less

than 1 μA in disable mode.

The LP3981 is available in 8-pin VSSOP-8 and 6-pin

WSON packages. Performance is specified for −40°C

to +125°C temperature range. The device available in

the following output voltages: 2.5 V, 2.7 V, 2.8 V,

2.83 V, 3 V, 3.03 V and 3.3 V as standard. Other

output options can be made available; contact your local TI sales office for more information.