SI91841 Datasheet, PDF (1/9 Pages) Vishay Siliconix – 150-mA Ultra Low-Noise LDO Regulator With Discharge Option

Si91841/3
Vishay Siliconix
150-mA Ultra Low-Noise LDO Regulator
With Discharge Option
FEATURES
D Ultra Low Dropout—130 mV at 150-mA Load
D Ultra Low Noise—30 mV_(rms) (10-Hz to 100-kHz
Bandwidth)
D Shutdown Control
D 110-mA Ground Current at 150-mA Load
D 1.5% Guaranteed Output Voltage Accuracy
D 300-mA Peak Output Current Capability
D Uses Low ESR Ceramic Capacitors
D Fast Start-Up (50 ms)
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 Si91841: Output, Auto-Discharge In Shutdown Mode
D Si91843: Output, No-Discharge In Shutdown Mode
D Fixed 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 Thin 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 Si91841/3 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 makes this part
attractive for battery operated power systems. The Si91841/3
also offers ultra low dropout voltage to prolong battery life in
portable electronics. Systems requiring a quiet voltage
source, such as RF applications, will benefit from the
Si91841/3’s ultra low output noise. An external noise bypass
capacitor connected to the device’s BP pin can further reduce
the noise level. The Si91841/3 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 Si91841/3 to clamp the output
voltage when it rises beyond normal regulation. The Si91841
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 Si91841/3 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.
The Si91841/3 is available in both standard and lead (Pb)-free
packages.
TYPICAL APPLICATION CIRCUIT
Si91841/3
V_IN
1 V_IN
V_OUT 5
1 mF
2 GND
V_OUT
1 mF
SD
3 SD
BP 4
Thin SOT-23, 5-Lead
10 nF
Document Number: 71447
S-40592—Rev. C, 29-Mar-04
www.vishay.com
1