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.