LP3905 Power Management Unit For Low Power Handheld Applications
August 2006
LP3905
Power Management Unit For Low Power Handheld
Applications
General Description
LP3905 is a multi-functional Power Management Unit,
optimized for low power handheld applications. This device
integrates two 600mA DC/DC buck regulators and two
150mA linear regulators. Fixed and adjustable buck output
versions are available. The LP3905 additionally features two
enable pins for the device output control and is offered in an
LLP package.
Key Specifications
Buck Regulators
n
Fixed and adjustable voltage options, range 1.0V to
3.3V *
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Up to 90% Efficiency
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Auto-switching PFM-PWM mode and fixed PWM mode
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2MHz PWM fixed switching frequency (Typ)
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600mA output current
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卤
4% output voltage accuracy over temp.
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Internal softstart
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2.2碌H inductor, 10碌F Input and 10碌F output Caps
Linear Regulators
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Output options in the range 1.5V to 3.3V *
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13.5碌V
rms
output voltage noise
n
PSRR - 70dB
@
1kHz
n
卤
3% output voltage accuracy over full line and load
regulation
n
0mA to 150mA output current
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C
in
= 1.0碌F, C
out
= 0.47碌F for 100mA O/P
C
in
= 1.0碌F, C
out
= 1.0碌F for 150mA O/P
80mV Dropout voltage
* Fixed output voltage devices can be customized to fit
system requirements. Please contact National Semiconduc-
tor Sales Office.
Features
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Two buck regulators for powering high current processor
functions or peripheral devices
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Two linear regulators for powering internal processor
functions and I/Os
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One enable pin for Buck1 and Linear Regulators 1 & 2
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Separate enable pin for Buck2
n
Thermal and current overload protection
n
Small 14鈥揚in LLP package (4mm x 4mm x 0.8mm)
Applications
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n
n
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Baseband Processors
Peripheral Processor (Video, Audio)
I/O Power
FPGA Power
Typical Application Circuit
20152901
FIGURE 1. Typical Application Circuit 鈥?14 Pin LLP Package
漏 2006 National Semiconductor Corporation
DS201529
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