下载
LP3974
www.ti.com
SNVS645A –OCTOBER 2011–REVISED OCTOBER 2011
LP3974
PRODUCT BRIEF High Performance Power Management Unit for Application Processors
Check for Samples: LP3974
1
FEATURES
• 5 Wide-Input Low-Output (WILO) LDOs
– 2 x 10 mA
2
• Linear Charger with Single Input
– 1 x 50 mA
– USB or AC Adapter Input
– 2 x 150 mA
– 28V OVP on the Charger Input
• All LDOs S/W Configurable
• Four High-Efficiency Synchronous Magnetic
Buck Regulators:
• Two Over-Voltage Protected Outputs for USB
Transceivers
– 2 x 1A, 2 x 800 mA
• Real Time Clock with Two Alarms
– 2 Regulators Have DVS Support
• Back-Up Battery Charger
– High-Efficiency ECO Mode @ low I
OUT
• Momentary Power Loss Detection
– Can Be Used with Inductors as Low as 1µH
@ 4MHz Clock
• Interrupt Request to Reduce S/W Polling
– Buck1, Buck2 and Buck4 Have Ramp
• I
2
C-Compatible Serial Interface
Control to Change Rate of Change of
• 100-Bump 0.4 mm Pitch Micro SMDxt Package
Output
• 11 General-Type Low Noise LDOs
APPLICATIONS
– 7 x 300 mA
• Smartphones
– 2 x 450 mA
• GSM, GPRS, EDGE, CDMA & WCDMA
– 2 x 150 mA Handsets
DESCRIPTION
The LP3974 is designed to meet the power management requirements of the latest cellular phones. The LP3974
PMU contains a single-input Li-Ion battery charger, 16 low-dropout voltage regulators (including 5 wide input low-
output regulators, 2 over-voltage protected voltage regulators, and 4 buck regulators), dual DPDT analog
switches, real time clock, and backup battery charger. Programming is handled via an I
2
C-compatible high-speed
Serial Interface allowing control of program on/off conditions and the output voltages of individual regulators, and
to read status information of the PMU. It can charge and maintain a single cell Li-Ion battery operating from an
AC adapter or USB power source.
The Li-Ion charger requires few external components and integrates the power FET. Charging is thermally
regulated to obtain the most efficient charging rate for a given ambient temperature. Over-Voltage Protection
(OVP) circuit at the charger input protects the PMU from input voltages up to +28V, eliminating the need for any
external protection circuitry. Buck regulators have an automatic switch to ECO mode at low load conditions
providing very good efficiency at low output currents. General-type LDO regulators provide excellent PSRR and
ULTRA LOW NOISE, 45 μV typ., ideally suited for supplying voltage to RF section. The real-time clock/calendar
provides time interval information as well as two programmable alarms.
To accommodate different processor requirements, the LP3974 PMU can have three different default voltage
settings and startup sequences selected by external pin.
Note: This document is not a full datasheet. For more information regarding this product or to order samples
please contact your local National Semiconductor sales office or visit http://www.national.com/support/dir.html
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.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2011, 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.
