Si91872
Vishay Siliconix
300-mA Low-Noise LDO Regulator
With Error Flag and Discharge Option
FEATURES
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Ultra Low Dropout鈥?00 mV at 300-mA Load
Low Noise鈥?5
mV
RMS
(10-Hz to 100-kHz)
Out-of-Regulation Error Flag (power good)
Shutdown Control
130-mA Ground Current at 300-mA Load
Fast Start-Up (50
mS)
1.5% Guaranteed Output Voltage Accuracy
400-mA Peak Output Current Capability
Uses Low ESR Ceramic Capacitors
Fast Line and Load Transient Response (v 30
ms)
1-mA Maximum Shutdown Current
Output Current Limit
Reverse Battery Protection
Built-in Short Circuit and Thermal Protection
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Output鈥擜uto-Discharge In Shutdown Mode
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Fixed 1.2, 1.8, 2.5, 2.6, 2.8, 3.0, 3.3, 5.0-V Output
Voltage Options
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MLP33-5 PowerPAKr Package
Available
APPLICATIONS
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Cellular Phones, Wireless Handsets
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Noise-Sensitive Electronic Systems, Laptop and
Palmtop Computers
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PDAs
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Pagers
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Digital Cameras
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MP3 Player
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Wireless Modem
DESCRIPTION
The Si91872 is a 300-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 Si91872 also offers ultra low dropout voltage to prolong
battery life in portable electronics. Systems requiring a quiet
voltage source will benefit from the Si91872鈥檚 low output noise.
The Si91872 is designed to maintain regulation while
delivering 400-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 Si91872 to clamp the output
voltage when it rises beyond normal regulation. The Si91872
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 Si91872 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 Si91872 is available in both the standard and
lead (Pb)-free 5-pin MLP33 PowerPAK packages and is
specified to operate over the industrial temperature range of
鈭?0_C
to 85_.
TYPICAL APPLICATION CIRCUIT
Si91872
V
IN
2.2
mF
SD
SD
51 kW
V
IN
V
OUT
V
OUT
2.2
mF
GND
ERROR
ERROR
MLP33-5
Document Number: 72013
S-51147鈥擱ev. F, 20-Jun-05
www.vishay.com
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