1 Features

1• Input Voltage: 2.5 V to 6 V

• 100-mV Maximum Dropout with 150-mA Load

• 150-mA Verified Output

• 50-dB PSRR at 1 kHz at VIN = VOUT + 0.2 V

• ≤ 1.5-μA Quiescent Current when Shut Down

• Fast Turn-On time: 200 μs (typ.)

• 30-μV RMS Output Noise (typical) over 10 Hz to 100

kHz

• −40°C to 125°C Junction Temperature Range for

Operation

• 2.5-V, 2.6-V, 2.7-V, 2.8-V, 2.85-V, 2.9-V, 3-V, 3.1-

V, 3.2-V, 3.3-V, 4.7-V, 4.75-V, 4.8-V and 5-V

Outputs Standard

• Logic Controlled Enable

• Stable with Ceramic and High-Quality Tantalum

Capacitors

• Fast Turnon

• Thermal Shutdown and Short-Circuit Current Limit

2 Applications

• CDMA Cellular Handsets

• Wideband CDMA Cellular Handsets

• GSM Cellular Handsets

• Portable Information Appliances

3 Description

The LP3985 is designed for portable and wireless

applications with demanding performance and space requirements. LP3985 performance 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.

The LP3985 is stable with a small 1-μF ±30%

ceramic or high-quality tantalum output capacitor. The

DSBGA requires the smallest possible PC board area

- the total application circuit area can be less than 2

mm x 2.5 mm, a fraction of a 1206 case size.

An optional external bypass capacitor reduces the

output noise without slowing down the load transient

response. Fast startup time is achieved by utilizing an

internal power-on circuit that actively pre-charges the

bypass capacitor.

Power supply rejection is better than 50 dB at low

frequencies and starts to roll off at 1 kHz. High power

supply rejection is maintained down to low 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 150 mA, from a 2.5-V to 6-V input. The LP3985

consumes less than 1.5 μA in disable mode and has

fast turn-on time less than 200 μs.

The LP3985 is available with fixed output voltages

from 2.5 V to 5 V. Contact Texas Instruments Sales

for specific voltage option needs.