LTC3525-3/
LTC3525-3.3/LTC3525-5
400mA Micropower
Synchronous Step-Up DC/DC
Converter with Output Disconnect
FeaTures
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DescripTion
The LTC
®
3525-3/LTC3525-3.3/LTC3525-5 are high efficiency
synchronous step-up DC/DC converters with output discon-
nect that can start up with an input as low as 0.85V. They
offer a compact, high efficiency alternative to charge pumps
in single cell or dual cell alkaline or Li-Ion applications. Only
three small external components are required. The LTC3525
is offered in fixed output voltages of 3V, 3.3V or 5V.
The device includes a 0.5Ω N-channel MOSFET switch and
a 0.8Ω P-channel synchronous rectifier. Peak switch current
ranges from 150mA to 400mA, depending on load, providing
enhanced efficiency. Quiescent current is an ultralow 7µA,
maximizing battery life in portable applications.
Other features include <1µA shutdown current, anti-
ringing control and thermal shutdown. The LTC3525 is
available in a tiny 6-Lead SC70 package.
List of LTC3525 Options
PART NAME
LTC3525-3
LTC3525-3.3
LTC3525-5
LTC3525D-3.3
LTC3525L-3
INPUT START-UP
VOLTAGE
0.85V
0.85V
0.85V
0.85V
0.7V
OUTPUT
VOLTAGE
3V
3.3V
5V
3.3V
3V
V
OUT
STATUS IN
SHUTDOWN MODE
Output Disconnect
Output Disconnect
Output Disconnect
Pass Through Mode
Output Disconnect
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Up to 95% Efficiency
Output Disconnect and Inrush Current Limit
Fixed Output Voltages of 3V, 3.3V or 5V
Delivers 65mA at 3V from a 1V Input
Delivers 60mA at 3.3V from a 1V Input,
or 140mA at 3.3V from a 1.8V Input
Delivers 175mA at 5V from a 3V Input
Burst Mode
®
Operation: I
Q
= 7µA
Only Three External Components
V
IN
> V
OUT
Operation
<1µA Shutdown Current
Antiringing Control
Short-Circuit and Overtemperature Protection
Very Low Profile of 1mm
Tiny 6-Lead SC70 Package
applicaTions
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MP3 Players
Portable Instruments
Glucose Meters
Digital Cameras
L,
LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Patents pending.
Typical applicaTion
L1*
10µH
100
90
LTC3525-3.3
V
IN
OFF ON
1µF
SHDN
GND
SW
V
OUT
GND
V
OUT
3.3V
60mA
10µF
EFFICIENCY (%)
80
70
60
50
40
30
LTC3525-3.3 Efficiency and Power
Loss vs Load Current
100
10
EFFICIENCY
1
POWER LOSS (mW)
V
IN
1V TO 1.6V
POWER LOSS
0.1
V
IN
= 3V
V
IN
= 2.4V
V
IN
= 1.2V
0.1
1
10
LOAD (mA)
100
3525 TA01
*MURATA LQH32CN100K53
20
0.01
0.01
1000
LT3525 • TA02
3525fc
For more information
www.linear.com/LTC3525
1
LTC3525-3/
LTC3525-3.3/LTC3525-5
(Note 1)
absoluTe MaxiMuM raTings
pin conFiguraTion
TOP VIEW
SHDN
1
GND 2
V
IN
3
6 SW
5 GND
4 V
OUT
V
IN
, V
OUT
Voltage ........................................ – 0.3V to 6V
SW Voltage ................................................. – 0.3V to 6V
SW Voltage < 100ns.................................... –0.3V to 7V
SHDN
Voltage ............................................. –0.3V to 6V
Operating Junction Temperature Range
(Notes 2, 5) ............................................ –40°C to 125°C
Storage Temperature Range .................. –65°C to 125°C
Lead Temperature (Soldering, 10 sec)................... 300°C
SC6 PACKAGE
6-LEAD PLASTIC SC70
T
JMAX
= 125°C
θ
JA
= 256°C/W IN FREE AIR,
θ
JA
= 150°C/W ON BOARD OVER GROUND PLANE
orDer inForMaTion
LEAD FREE FINISH
LTC3525ESC6-3#PBF
LTC3525ISC6-3#PBF
LTC3525ESC6-3.3#PBF
LTC3525ISC6-3.3#PBF
LTC3525ESC6-5#PBF
LTC3525ISC6-5#PBF
TAPE AND REEL
LTC3525ESC6-3#TRPBF
LTC3525ISC6-3#TRPBF
LTC3525ESC6-3.3#TRPBF
LTC3525ISC6-3.3#TRPBF
LTC3525ESC6-5#TRPBF
LTC3525ISC6-5#TRPBF
PART MARKING
LCDR
LCDR
LBTG
LBTG
LBWT
LBWT
PACKAGE DESCRIPTION
6-Lead Plastic SC70
6-Lead Plastic SC70
6-Lead Plastic SC70
6-Lead Plastic SC70
6-Lead Plastic SC70
6-Lead Plastic SC70
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
2
3525fc
For more information
www.linear.com/LTC3525
LTC3525-3/
LTC3525-3.3/LTC3525-5
(LTC3525-3)
The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
T
A
= 25°C. V
IN
= 1.2V, V
SHDN
= 1.2V, V
OUT
= 3V unless otherwise noted. (Note 2)
PARAMETER
Input Start-Up Voltage
Output Voltage
Quiescent Current, V
OUT
Quiescent Current, V
IN
Quiescent Current, V
IN
– Shutdown
NMOS Switch Leakage Current
PMOS Switch Leakage Current
NMOS Switch On-Resistance
PMOS Switch On-Resistance
Peak Current Limit
SHDN
Threshold Voltage
SHDN
Input Current
V
SHDN
= V
IN
or V
OUT
(Note 6)
SHDN
= V
IN
(Note 4)
SHDN
= V
IN
(Note 4)
SHDN
= 0V, V
OUT
= 0V
Not Including Switch Leakage
V
IN
= V
OUT
= V
SW
= 5V,
SHDN
= 0V
V
IN
= V
SW
= 5V, V
OUT
= 0V,
SHDN
= 0V
(Note 3)
(Note 3)
0.4
0.4
l
elecTrical characTerisTics
CONDITIONS
MIN
2.91
TYP
0.85
3.00
7
0.5
0.1
0.1
0.1
0.6
0.9
0.45
0.6
0.01
MAX
1
3.09
15
3
1
1
3
UNITS
V
V
µA
µA
µA
µA
µA
Ω
Ω
A
1
1
V
µA
(LTC3525-3.3)
The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
T
A
= 25°C. V
IN
= 1.2V, V
SHDN
= 1.2V, V
OUT
= 3.3V unless otherwise noted. (Note 2)
PARAMETER
Input Start-Up Voltage
Output Voltage
Quiescent Current, V
OUT
Quiescent Current, V
IN
Quiescent Current, V
IN
– Shutdown
NMOS Switch Leakage Current
PMOS Switch Leakage Current
NMOS Switch On-Resistance
PMOS Switch On-Resistance
Peak Current Limit
SHDN
Threshold Voltage
SHDN
Input Current
V
SHDN
= V
IN
or V
OUT
(Note 6)
SHDN
= V
IN
(Note 4)
SHDN
= V
IN
(Note 4)
SHDN
= 0V, V
OUT
= 0V
Not Including Switch Leakage
V
IN
= V
OUT
= V
SW
= 5V,
SHDN
= 0V
V
IN
= V
SW
= 5V, V
OUT
= 0V,
SHDN
= 0V
(Note 3)
(Note 3)
0.4
0.4
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elecTrical characTerisTics
CONDITIONS
MIN
3.20
TYP
0.85
3.30
7
0.5
0.1
0.1
0.1
0.5
0.8
0.45
0.6
0.01
MAX
1
3.40
15
3
1
1
3
UNITS
V
V
µA
µA
µA
µA
µA
Ω
Ω
A
1
1
V
µA
3525fc
For more information
www.linear.com/LTC3525
3
LTC3525-3/
LTC3525-3.3/LTC3525-5
(LTC3525-5)
The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
T
A
= 25°C. V
IN
= 2.4V, V
SHDN
= 2.4V, V
OUT
= 5V unless otherwise noted. (Note 2)
PARAMETER
Input Start-Up Voltage
Output Voltage
Quiescent Current, V
OUT
Quiescent Current, V
IN
Quiescent Current, V
IN
– Shutdown
NMOS Switch Leakage Current
PMOS Switch Leakage Current
NMOS Switch On-Resistance
PMOS Switch On-Resistance
Peak Current Limit
SHDN
Threshold Voltage
SHDN
Input Current
V
SHDN
= V
IN
or V
OUT
(Note 6)
SHDN
= V
IN
(Note 4)
SHDN
= V
IN
(Note 4)
SHDN
= 0V, V
OUT
= 0V
Not Including Switch Leakage
V
IN
= V
OUT
= V
SW
= 5V,
SHDN
= 0V
V
IN
= V
SW
= 5V, V
OUT
= 0V,
SHDN
= 0V
(Note 3)
(Note 3)
0.4
0.4
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CONDITIONS
MIN
4.85
TYP
0.85
5.00
8
1.5
0.1
0.1
0.1
0.4
0.7
0.5
0.6
0.01
MAX
1
5.15
18
5
1
1
3
UNITS
V
V
µA
µA
µA
µA
µA
Ω
Ω
A
1
1
V
µA
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 LTC3525 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3525E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3525I is guaranteed
over the –40°C to 125°C operating junction temperature range. Note that
the maximum ambient temperature consistent with these specifications
is determined by specific operating conditions in conjunction with board
layout, the rated package thermal impedance and other environmental
factors. T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
• 150°C/W)
Note 3:
Specification is guaranteed by design and not 100% tested in
production.
Note 4:
Current Measurements are performed when the LTC3525 is not
switching.
Note 5:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 6:
Consult LTC Marketing for other output voltage options.
4
3525fc
For more information
www.linear.com/LTC3525
LTC3525-3/
LTC3525-3.3/LTC3525-5
Typical perForMance characTerisTics
T
A
= 25°C unless otherwise noted.
300
250
200
I
OUT
(mA)
150
100
50
0
0.5
50
LTC3525-3
LTC3525-5
LOAD (mA)
Maximum Output Current vs V
IN
(for V
OUT
to Drop 2.5%)
LTC3525-3.3
Maximum Startup Load vs V
IN
(Resistive Load)
250
LTC3525-5
50
45
40
35
I
IN
(µA)
150
LTC3525-3.3
30
25
20
15
10
5
No-Load Input Current vs V
IN
200
LTC3525-5
100
LTC3525-3
LTC3525-3.3
1.0
1.5
2.0
2.5 3.0
V
IN
(V)
3.5
4.0
4.5
0
0.5
1.0
1.5
2.0
V
IN
(V)
2.5
3.0
3525 G02
0
1.0
1.5
2.0
2.5 3.0
V
IN
(V)
3.5
4.0
4.5
3525 G01
3525 G03
LTC3525-3 Efficiency and Power
Loss vs Load
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
0.01
0.1
1
10
LOAD (mA)
V
IN
= 2.4V
V
IN
= 1.2V
100
0.1
EFFICIENCY
1
10
POWER LOSS (mW)
100
100
90
80
EFFICIENCY (%)
70
60
50
40
30
LTC3525-3.3 Efficiency and Power
Loss vs Load
100
100
90
10
EFFICIENCY
1
80
EFFICIENCY (%)
70
60
50
40
30
20
10
LTC3525-5 Efficiency and Power
Loss vs Load
1000
100
EFFICIENCY
10
POWER LOSS
POWER LOSS (mW)
POWER LOSS (mW)
POWER LOSS
POWER LOSS
1
0.1
V
IN
= 3V
V
IN
= 2.4V
V
IN
= 1.2V
0.1
1
10
LOAD (mA)
100
0.01
1000
20
0.01
0.01
1000
0
0.01
0.1
1
10
LOAD (mA)
V
IN
= 3.6V 0.1
V
IN
= 2.4V
V
IN
= 1.2V
0.01
100
1000
3525 G05
3525 G24
3525 G04
LTC3525-3.3 Load Regulation
2.5
2.0
1.5
CHANGE IN V
OUT
(%)
CHANGE IN V
OUT
(%)
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
0
10
20
30 40 50
LOAD (mA)
60
70
80
C
OUT
= 10µF
C
OUT
= 22µF
V
IN
= 1.2V
2.5
2.0
1.5
LTC3525-3.3 Load Regulation
V
IN
= 2.4V
2.5
2.0
1.5
CHANGE IN V
OUT
(%)
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0
20
40
60
80 100 120 140 160 180
LOAD (mA)
3525 G07
LTC3525-5 Load Regulation
V
IN
= 1.2V
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
C
OUT
= 22µF
C
OUT
= 10µF
C
OUT
= 22µF
C
OUT
= 10µF
–2.5
0
10
20
30
40
LOAD (mA)
50
60
3525 G08
3525 G06
3525fc
For more information
www.linear.com/LTC3525
5
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