Si91842/4

Vishay Siliconix

New Product

Document Number: 71732

S-20478—Rev. C, 01-Apr-02

www.vishay.com

1

150-mA Low-Noise LDO Regulator

With Error Flag and Discharge Option

FEATURES

D Ultra Low Dropout—130 mV at 150-mA Load

D Out-of-Regulation Error Flag (power good)

D Shutdown Control

D 110-mA Ground Current at 150-mA Load

D Fast Start-Up (50 mS)

D 1.5% Guaranteed Output Voltage Accuracy (1.2 V, 2%)

D 300-mA Peak Output Current Capability

D Uses Low ESR Ceramic Capacitors

D Fast Line and Load Transient Response (v 30 ms)

D 1-mA Maximum Shutdown Current

D Output Current Limit

D Reverse Battery Protection

D Built-in Short Circuit and Thermal Protection

D Si91842: Output—Auto-Discharge In Shutdown Mode

D Si91844: Output—No-Discharge In Shutdown Mode

D Fixed 1.2, 1.8, 2.0, 2.2, 2.5, 2.6, 2.7, 2.8, 2.85, 2.9, 3.0,

3.3, 3.5, 3.6, 5.0-V Output Voltage Options

D SOT23-5 Package

APPLICATIONS

D Cellular Phones, Wireless Handsets

D Noise-Sensitive Electronic Systems, Laptop and

Palmtop Computers

D PDAs

D Pagers

D Digital Cameras

D MP3 Player

D Wireless Modem

DESCRIPTION

The Si91842/4 is a 150-mA CMOS LDO (low dropout) voltage

regulator. It is the perfect choice for low voltage, low power

applications. An ultra low ground current and ultra fast turn-on

make this part attractive for battery operated power systems.

The Si91842/4 also offers ultra low dropout voltage to prolong

battery life in portable electronics. Systems requiring a quiet

voltage source will benefit from the Si91842/4’s low output

noise. The Si91842/4 is designed to maintain regulation while

delivering 300-mA peak current, making it ideal for systems

that have a high surge current upon turn-on.

For better transient response and regulation, an active

pull-down circuit is built into the Si91842/4 to clamp the output

voltage when it rises beyond normal regulation. The Si91842

automatically discharges the output voltage by connecting the

output to ground through a 100-

W n-channel MOSFET when

the device is put in shutdown mode.

The Si91842/4 features reverse battery protection to limit

reverse current flow to approximately 1-

mA in the event

reversed battery is applied at the input, thus preventing

damage to the IC.

TYPICAL APPLICATION CIRCUIT

3

2

Si91842/4

1

4

5

GND

SD

ERROR

SD

1

mF

1

mF

51 k

W

5

ERROR

SOT-23, 5-Lead