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EN1
EN2
TGND
GND
LDO2
Vin2
LDO1
0.47 PF
0.47 PF
1.0 PF
Enable 1
LDO2
Output
LDO1
Output
VSupply
10 PF
10 PF
FB2
FB1
GND_B2
GND_B1
Vin1
SW1
SW2
LP3905
Buck1
Output
Buck2
Output
VSupply
2.2 PH
2.2 PH
LDO GND
BUCK GND
10 PF
SGND
Enable 2
LP3905
www.ti.com
SNVS374D –JUNE 2006–REVISED MAY 2013
LP3905 Power Management Unit For Low Power Handheld Applications
Check for Samples: LP3905
1
FEATURES
KEY SPECIFICATIONS
Buck Regulators
• Two Buck Regulators for Powering High
Current Processor Functions or Peripheral
• Fixed and Adjustable Voltage Options, Range
Devices
1.0V to 3.3V
(1)
• Two Linear Regulators for Powering Internal
• Up to 90% Efficiency
Processor Functions and I/Os
• Auto-Switching PFM-PWM Mode and Fixed
• One Enable Pin for Buck1 and Linear
PWM Mode
Regulators 1 and 2
• 2MHz PWM Fixed Switching Frequency (Typ)
• Separate Enable Pin for Buck2
• 600mA Output Current
• Thermal and Current Overload Protection
• ±4% Output Voltage Accuracy Over Temp
• Small 14–Pin WSON Package (4x4mmx0.8mm)
• Internal SoftStart
• 2.2µH Inductor, 10µF Input and Output Caps
APPLICATIONS
Linear Regulators
• Baseband Processors
• Output Options in the Range 1.5V to 3.3V
(1)
• Peripheral Processor (Video, Audio)
• 13.5µV
rms
Output Voltage Noise
• I/O Power
• PSRR - 70dB @ 1kHz
• FPGA Power
• ±3% Output Voltage Accuracy Over Full Line
and Load Regulation
DESCRIPTION
• 0mA to 150mA Output Current
LP3905 is a multi-functional Power Management Unit,
optimized for low power handheld applications. This
• C
in
= 1.0µF, C
out
= 0.47µF for 100mA O/P
device integrates two 600mA DC-DC buck regulators
• C
in
= 1.0µF, C
out
= 1.0µF for 150mA O/P
and two 150mA linear regulators. Fixed and
• 80mV Dropout Voltage
adjustable buck output versions are available. The
LP3905 additionally features two enable pins for the
device output control and is offered in an WSON
(1) Fixed output voltage devices can be customized to fit system
package. requirements. Please contact Texas Instruments Sales Office.
Typical Application Circuit
Figure 1. Typical Application Circuit – 14-Pin WSON Package
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Copyright © 2006–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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