LM3280_15 Datasheet, PDF (1/27 Pages) Texas Instruments – Adjustable Step-Down DC-DC Converter and 3 LDOs for RF Power Management

LM3280
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SNOSAU4B – OCTOBER 2006 – REVISED FEBRUARY 2013
LM3280 Adjustable Step-Down DC-DC Converter and 3 LDOs for RF Power Management
Check for Samples: LM3280
FEATURES
1
•2 2MHz (typ.) PWM Switching Frequency
• Operates from a Single Li-Ion Cell (2.7V to
5.5V)
• Adjustable Output Voltage (0.8V to 3.6V) DC-
DC
• High-Efficiency Synchronous Buck Converter
• 300mA Maximum Load Capability (PWM Mode)
• 500mA Maximum Load Capability (Bypass
mode)
• PWM, Forced and Automatic Bypass Mode
• 3 Low-Dropout and Fast Transient Response
LDOs
• 16-pin DSBGA Package
• Current Overload Protection
• Thermal Overload Protection
DESCRIPTION
The LM3280 is a multi-functional Power Management
Unit, optimized for low-power handheld applications
such as Cellular Phones.
The LM3280 incorporates three low-dropout LDO
voltage regulators and one step down PWM DC-DC
converter with an internal Bypass FET. The step
down converter's output voltage can be set using an
analog input (V_CON) for optimizing efficiency of the RF
PA at various power levels. The LDO operates a
nominal output voltage of 2.85V and maximum load
current capability of 20mA for a reference voltage
required by linear RF power amplifiers. The LM3280
additionally features a separate enable pin for each
output.
The LM3280 is available in a 16-pin lead free DSBGA
package.
APPLICATIONS
• Cellular Phones
• Hand-Held Radios
• Battery Powered RF Devices
Typical Application
V_IN :
2.7V to 5.5V
C3
1 éF
C1
10 éF
V_CON :
0.267V to 1.200V
DAC
ON/OFF
SVIN PVIN
V_CON
BYP
BYPOUT
SW
FB
EN_BUCK
LM3280
LDO1
éPC
ON/OFF
ON/OFF
EN_LDO1
EN_LDO2
LDO2
ON/OFF
EN_LDO3 SGND PGND
LDO3
L1
2.2 éH
V_OUT :
0.8V to 3.6V
C2
4.7 éF
V_OUT = 3 x V_CON
V_LDO1 : 2.85V
V_RE
C5
1 éF
F
V_LDO2 :2.85V
V_RE
C6
1 éF
F
V_LDO3 : 2.85V
C7
1 éF
V_RE
F
PA V_CC
PA
BAND1
PA
BAND2
PA
BAND3
Figure 1. LM3280 Typical Application
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2006–2013, Texas Instruments Incorporated