LM3280 DC-DC Converter Datasheet

LM3280 Datasheet, PDF, Equivalent


Part Number

LM3280

Description

Adjustable Step-Down DC-DC Converter

Manufacture

etcTI

Total Page 26 Pages
Datasheet
Download LM3280 Datasheet


LM3280
LM3280
www.ti.com
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 (VCON) 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
VIN :
2.7V to 5.5V
C3
1 éF
C1
10 éF
VCON :
0.267V to 1.200V
DAC
ON/OFF
SVIN PVIN
VCON
BYP
BYPOUT
SW
FB
ENBUCK
LM3280
LDO1
éPC
ON/OFF
ON/OFF
ENLDO1
ENLDO2
LDO2
ON/OFF
ENLDO3 SGND PGND
LDO3
L1
2.2 éH
VOUT :
0.8V to 3.6V
C2
4.7 éF
VOUT = 3 x VCON
VLDO1 : 2.85V
VRE
C5
1 éF
F
VLDO2 :2.85V
VRE
C6
1 éF
F
VLDO3 : 2.85V
C7
1 éF
VRE
F
PA VCC
PA
BAND1
PA
BAND2
PA
BAND3
Figure 1. LM3280 Typical Application
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.
All trademarks are the property of their respective owners.
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

LM3280
LM3280
SNOSAU4B – OCTOBER 2006 – REVISED FEBRUARY 2013
Connection Diagrams
A LDO1
SVIN
SGND
BYPOUT
www.ti.com
B LDO2
FB
ENBUCK
PVIN
C LDO3
ENLDO2
ENLDO1
SW
D ENLDO3
VCON
BYP
PGND
1234
Top View
Figure 2. 16–Bump DSBGA Package, Large Bump
See Package Number YZR0016QQA
Pin #
A1
B1
C1
D1
A2
B2
C2
D2
A3
B3
C3
D3
A4
B4
C4
D4
Name
LDO1
LDO2
LDO3
ENLDO3
SVIN
FB
ENLDO2
VCON
SGND
ENBUCK
ENLDO1
BYP
BYPOUT
PVIN
SW
PGND
Pin Descriptions
Description
LDO1 Output.
LDO2 Output.
LDO3 Output.
LDO3 Enable Input. Set this digital input high to turn on LDO3. (ENBUCK pin must be also set high.) For
turning LDO3 off, set low.
Analog, Signal, and LDO Supply Input.
Buck Converter Feedback Analog Input. Connect to the output at the output filter capacitor.
LDO2 Enable Input. Set this digital input high to turn on LDO2. (ENBUCK pin must be also set high.) For
turning LDO2 off, set low.
Buck Converter Voltage Control Analog Input. This pin controls VOUT in PWM mode. Set: VOUT = 3 x VCON. Do
not leave floating.
Analog, Signal, and LDO Ground.
Buck Converter Enable Input. Set this digital input high after Vin >2.7V for normal operation. For shutdown,
set low.
LDO1 Enable Input. Set this digital input high to turn on LDO1. (ENBUCK pin must be also set high.) For
turning LDO1 off, set low.
Forced Bypass Input. Use this digital input to command operation in Bypass mode. Set BYP low (<0.4V) for
normal operation.
Bypass FET Drain. Connect to the output capacitor. Do not leave floating.
Buck Converter Power Supply Voltage Input to the internal PFET switch and Bypass FET.
Buck Converter Switch Node connection to the internal PFET switch and NFET synchronous rectifier.
Connect to an inductor with a saturation current rating that exceeds the maximum Switch Peak Current Limit
of the PWM Buck Converter.
Buck Converter Power Ground.
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
2 Submit Documentation Feedback
Product Folder Links: LM3280
Copyright © 2006–2013, Texas Instruments Incorporated


Features LM3280 www.ti.com SNOSAU4B – OCTOBER 2006 – REVISED FEBRUARY 2013 LM3280 Adjustable Step-Down DC-DC Converter a nd 3 LDOs for RF Power Management Check for Samples: LM3280 FEATURES 1 •2 2 MHz (typ.) PWM Switching Frequency • Operates from a Single Li-Ion Cell (2.7 V to 5.5V) • Adjustable Output Voltag e (0.8V to 3.6V) DC- DC • High-Effici ency Synchronous Buck Converter • 300 mA Maximum Load Capability (PWM Mode) 500mA Maximum Load Capability (Bypas s mode) • PWM, Forced and Automatic B ypass Mode • 3 Low-Dropout and Fast T ransient Response LDOs • 16-pin DSBGA Package • Current Overload Protectio n • Thermal Overload Protection DESC RIPTION The LM3280 is a multi-functiona l Power Management Unit, optimized for low-power handheld applications such as Cellular Phones. The LM3280 incorporat es three low-dropout LDO voltage regula tors and one step down PWM DC-DC conver ter with an internal Bypass FET. The st ep down converter's output voltage can be set using an analog input (VCON) for optimizing.
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