features

Low Dropout Voltage Regulator, 1.2-V

150-mA Load Current Capability

Power Okay (POK) Function

Load Independent, Low Ground

Current,150-μA

Current Limiting

Thermal Shutdown

Low Sleep State Current (Off Mode)

Fast Transient Response

Low Variation Due to Load and Line

Regulation

Output Stable With Low ESR Capacitors

TTL Logic Controlled Enable Input

applications

Processor Powerup Sequencing

Palmtop Computers, Laptops, and

Notebooks

description

The SN105125 is a low dropout voltage regulator with an output tolerance of ±2% over the operating range. The

device is optimized for low noise applications and has a low quiescent current (enable <0.8 V). The device has

a low dropout voltage at full load (150 mA). The power okay function monitors the output voltage and indicates

when an error occurs in the system (active low). In the event of an output fault such as overcurrent, thermal

shutdown, or dropout, the power okay output is pulled low (open drain).

The SN105125 has a fast transient response recovery capability in the event of load transition from heavy load

to light load. The device also minimizes overshoot during this condition. During power down, the output

capacitor and load are de-energized through the internal active shutdown clamp, which is turned on when the

device is disabled.

The SN105125 requires a small output capacitor for stability with low ESR. An input capacitor is not required

unless the bulk ac capacitor is placed away from the device or the power supply is a battery. In this situation,

a 1-μF capacitor is recommended for the application. Low ESR ceramic capacitors may be used with the device

to reduce board space in power applications, a key concern in hand-held wireless devices.