LP3905 Datasheet, PDF (1/15 Pages) National Semiconductor (TI) – 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.
Features
n Two buck regulators for powering high current processor
functions or peripheral devices
n Two linear regulators for powering internal processor
functions and I/Os
n One enable pin for Buck1 and Linear Regulators 1 & 2
n Separate enable pin for Buck2
n Thermal and current overload protection
n Small 14–Pin LLP package (4mm x 4mm x 0.8mm)
Applications
n Baseband Processors
n Peripheral Processor (Video, Audio)
n I/O Power
n FPGA Power
Key Specifications
Buck Regulators
n Fixed and adjustable voltage options, range 1.0V to
3.3V *
n Up to 90% Efficiency
n Auto-switching PFM-PWM mode and fixed PWM mode
n 2MHz PWM fixed switching frequency (Typ)
n 600mA output current
n ±4% output voltage accuracy over temp.
n Internal softstart
n 2.2µH inductor, 10µF Input and 10µF output Caps
Linear Regulators
n Output options in the range 1.5V to 3.3V *
n 13.5µV_rms output voltage noise
n PSRR - 70dB @ 1kHz
n ±3% output voltage accuracy over full line and load
regulation
n 0mA to 150mA output current
n C_in = 1.0µF, C_out = 0.47µF for 100mA O/P
C_in = 1.0µF, C_out = 1.0µF 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.
Typical Application Circuit
FIGURE 1. Typical Application Circuit – 14 Pin LLP Package
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