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LTC3444EDD#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
1
LTC3444
3444fb
■
WCDMA Applications–3G Handsets with High Speed
Data Rate Capability
■
MP3 Players
■
Digital Cameras
Micropower Synchronous
Buck-Boost DC/DC Converter
for WCDMA Applications
■
Optimized Features for WCDMA Handsets
■
Regulated Output with Input Voltages
Above, Below, or Equal to the Output
■
0.5V to 5V Output Range
■
Up to 400mA Continuous Output Current From
a Single Lithium-Ion Cell
■
Minimal External Components
■
1.5MHz Fixed Frequency Operation
■
Internal Loop Compensation for Fast Response
<25μs Full Scale Output Slewing; C
OUT
4.7μF
■
Output Disconnect in Shutdown
■
2.75V to 5.5V Input
■
<1μA Shutdown Current
■
Internal Soft-Start
■
Output Overvoltage Protection
■
Single Inductor, No Schottky Diodes Required
■
Small, Thermally Enhanced 8-Lead (3mm × 3mm)
DFN Package
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
The LTC
®
3444 is a highly efficient, fixed frequency, buck-
boost DC/DC converter, which operates from input volt-
ages above, below, and equal to the output voltage. The
topology incorporated in the IC provides a continuous
transfer function through all operating modes, making the
product ideal for a single Lithium-Ion or multi-cell
applications where the output voltage can vary over a wide
range.
The LTC3444 has been optimized for use in 3G WCDMA
applications. A unique design yields high efficiency at
very low output voltages while also eliminating external
components. The high speed error amplifier provides the
fast transient response required to slew the RF power
amplifier from standby to transmit and transmit to stand
by power levels. Output overvoltage protection protects
the RF power amplifier.
Operating frequency is internally set to 1.5MHz to mini-
mize external component size while maximizing efficiency.
Other features include <1μA shutdown current, internal
soft-start, peak current limit and thermal shutdown. The
LTC3444 is available in a small, thermally enhanced
8-lead (3mm × 3mm) DFN package.
LTC3444
V
CONTROL
3.1V TO 4.2V
SW2
340k
4.7μF
2.2μH
4.7μF
V
OUT
0.8V TO 4.2V
205k
267k
V
OUT
FB
V
C
SW1
V
IN
SHDN
GND
DAC
+
Li-Ion
3444 TA01
LTC3444 Dynamic Response
V
IN
= 3.6V, V
OUT
= 0.8V TO 4.2V
V
CONTROL
= 2.36V TO 0.28V, I
LOAD
= 100mA
V
CONTROL
10μs/DIV
1V/DIV
V
OUT
3444 G16a
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6404251, 6166527.
2
LTC3444
3444fb
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
(Note 1)
LTC3444EDD
ORDER PART
NUMBER
DD PART MARKING
LBVZ
T
JMAX
= 125°C, θ
JA
= 43°C/W,
4-LAYER BOARD θ
JC
= 2.96°C/W
EXPOSED PAD IS GND (PIN 9)
MUST BE SOLDERED TO PCB
The
● denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
V
IN
= V
OUT
=
3.6V unless otherwise noted.
ELECTRICAL CHARACTERISTICS
V
IN
,V
OUT
Voltages .......................................... –0.3 to 6V
SW1,SW2 Voltages DC .................................. –0.3 to 6V
Pulsed <100ns ............... –0.3 to 7V
SHDN Voltage ................................................ –0.3 to 6V
Operating Temperature (Note 2) .............. –40°C to 85°C
Maximum Junction Temperature (Note 4) ............ 125°C
Storage Temperature Range .................. –65°C to 125°C
PARAMETER CONDITIONS MIN TYP MAX UNITS
Input Start-Up Voltage ● 2.55 2.65 2.75 V
Output Voltage Adjust Range ● 0.5 5 V
Feedback Voltage ● 1.19 1.22 1.25 V
Feedback Input Current V
FB
= 1.22V 1 50 nA
Quiescent Current - Shutdown SD = 0V, V
OUT
= 0V Not Including Switch Leakage 0.1 1 μA
Quiescent Current - Active (Note 3) 700 1100 μA
NMOS Switch Leakage Switches B and C 0.1 7 μA
PMOS Switch Leakage Switches A and D 0.1 10 μA
NMOS Switch On Resistance Switches B and C 0.19 Ω
PMOS Switch On Resistance Switches A and D 0.22 Ω
PMOS Switch On Resistance Switch D V
IN
= 3.6, V
OUT
= 1V 0.4 Ω
Input Current Limit ● 2.5 3.5 A
Reverse Current Limit ● 3A
Max Duty Cycle Boost (%Switch C On) ● 70 82 %
Buck (% Switch A On)
● 100 %
Min Duty Cycle ● 0%
Frequency Accuracy ● 1.2 1.5 1.8 MHz
Error Amp A
VOL
65 dB
Error Amp Source Current V
C
= 1.5V, FB = 0V 8 μA
Error Amp Sink Current V
C
= 1.5V, FB = 1.5V 230 μA
Internal Soft-Start Time SHDN Going High 250 μs
Output OV Threshold ● 5.1 5.3 5.5 V
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
TOP VIEW
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
5
6
7
8
4
3
2
1
9
SHDN
SW1
GND
SW2
FB
V
C
V
IN
V
OUT
3
LTC3444
3444fb
PARAMETER CONDITIONS MIN TYP MAX UNITS
SHDN Threshold (On) IC is Enabled ● 1.4 V
SHDN Threshold (Off) IC is Disabled ● 0.4 V
SHDN Input Current V
SHDN
= 3.6V 0.01 1 μA
V
C
Output Current V
C
= GND 0.5 2 μA
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
V
IN
= V
OUT
=
3.6V unless otherwise noted.
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3444E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: Current measurements are performed when the outputs are not
switching.
Note 4: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature is active.
Continuous operation above the specified maximum operating junction
temperature may result in device degradation or failure.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
(T
A
= 25°C unless otherwise specified)
Li-Ion to 1V Efficiency
OUTPUT CURRENT (mA)
20
10
40
30
EFFICIENCY (%)
POWER LOSS (W)
80
70
90
60
50
1 10 100
3444 G06
0
0.04
0.02
0.08
0.06
0.16
0.14
0.18
0.12
0.10
0
1000
V
IN
= 3.6V
V
IN
= 3.1V
V
IN
= 4.4V
V
IN
= 4.4V
V
IN
= 3.1V
PLOSS
Li-Ion to 3.3V Efficiency
OUTPUT CURRENT (mA)
20
10
40
30
EFFICIENCY (%)
POWER LOSS (W)
80
70
90
60
50
1 10 100
3444 G05
0
100
0.15
0.20
0.10
0.05
0
0.25
1000
V
IN
= 3.6V
V
IN
= 3.1V
V
IN
= 4.4V
V
IN
= 3.1V
V
IN
= 3.6V
PLOSS
Efficiency vs V
IN
V
IN
(V)
3.1 3.3
60
EFFICIENCY (%)
70
85
3.5
3.9
4.1
3444 G03
65
80
75
3.7
4.3
4.5
I
OUT
= 100mA
I
OUT
= 65mA
I
OUT
= 50mA
V
OUT
= 1.0V
Operating Frequency
TEMPERATURE (°C)
–55
1.2
FREQUENCY (MHz)
1.3
1.4
1.5
1.6
1.8
–25
03565
3444 G08
95 125
1.7
Error Amp Source Current
TEMPERATURE (°C)
–55
5
E/A SOURCE CURRENT (μA)
9
13
17
–25
5
35 65
3444 G07
95
7
11
15
19
125
V
C
= 1V
FB = 0V
Li-Ion to 4.2V Efficiency
OUTPUT CURRENT (mA)
20
10
40
30
EFFICIENCY (%)
POWER
LOSS
(W)
80
70
90
60
50
1 10 100
3444 G04
0
100
0.10
0.05
0.20
0.15
0.40
0.35
0.45
0.30
0.25
0
0.50
1000
V
IN
= 3.6V
V
IN
= 3.1V
V
IN
= 4.4V
V
IN
= 3.1V
V
IN
= 4.4V
PLOSS
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LTC3444EDD#PBF

Mfr. #:
Buy LTC3444EDD#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Micropower Sych Buck-Boost DC/DC Converter
Lifecycle:
New from this manufacturer.
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