LINER LTC3525D-3.3 400ma micropower synchronous step-up dc/dc converter with pass through mode Datasheet

LTC3525D-3.3
400mA Micropower
Synchronous Step-Up DC/DC
Converter with Pass Through Mode
Features
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Description
VOUT Connected to VIN in Shutdown
Up to 95% Efficiency
0.85V Minimum Input Start-Up Voltage
Fixed Output Voltage of 3.3V
Delivers 60mA at 3.3V from a 1V Input,
or 140mA at 3.3V from a 1.8V Input
Burst Mode® Operation: IQ = 7µA
VIN Range: 0.5V to 4.5V
Only Three External Components
VIN > VOUT Operation
Anti-Ringing Control
Short-Circuit and Overtemperature Protection
Very Low Profile of 1mm
Tiny 6-Lead SC70 Package
The LTC®3525D-3.3 is a high efficiency synchronous stepup DC/DC converter that can start up with an input as low
as 0.85V. It offers 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 LTC3525D features a fixed output voltage of 3.3V.
In shutdown, VOUT is connected to VIN through the inductor.
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 anti-ringing control and thermal
shutdown. The LTC3525D is available in a tiny 6-Lead
SC70 package.
Applications
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MP3 Players
Portable Instruments
Glucose Meters
Digital Cameras
List of LTC3525 Options
PART NAME
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.
INPUT START-UP
VOLTAGE
OUTPUT
VOLTAGE
VOUT STATUS IN
SHUTDOWN MODE
LTC3525-3
0.85V
3V
Output Disconnect
LTC3525-3.3
0.85V
3.3V
Output Disconnect
LTC3525-5
0.85V
5V
Output Disconnect
LTC3525D-3.3
0.85V
3.3V
LTC3525L-3
0.7V
3V
Typical Application
Pass Through Mode
Output Disconnect
LTC3525D-3.3 Efficiency and
Power Loss vs Load Current
L1*
10µH
100
100
90
PASS THROUGH ON
1µF
*MURATA LQH32CN100K53
SW
SHDN
VOUT
GND
GND
VOUT
3.3V
140mA
10µF
3525 TA01
EFFICIENCY (%)
VIN
70
10
POWER LOSS (mW)
80
LTC3525D-3.3
VIN
1.8V TO 3.2V
EFFICIENCY
60
1
POWER LOSS
50
40
0.1
VIN = 3V
VIN = 2.4V
VIN = 1.2V
30
20
0.01
0.1
1
10
LOAD (mA)
100
0.01
1000
LT3525 • TA02
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1
LTC3525D-3.3
Absolute Maximum Ratings
Pin Configuration
(Note 1)
VIN, VOUT 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
TOP VIEW
SHDN 1
6 SW
GND 2
5 GND
VIN 3
4 VOUT
SC6 PACKAGE
6-LEAD PLASTIC SC70
TJMAX = 125°C
θJA = 256°C/W IN FREE AIR, θJA = 150°C/W ON BOARD OVER GROUND PLANE
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC3525DESC6-3.3#PBF
LTC3525DESC6-3.3#TRPBF
LCQZ
6-Lead Plastic SC70
–40°C to 85°C
LTC3525DISC6-3.3#PBF
LTC3525DISC6-3.3#TRPBF
LCQZ
6-Lead Plastic SC70
–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/
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LTC3525D-3.3
Electrical Characteristics
The l denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
TA = 25°C. VIN = 1.2V, VSHDN = 1.2V, VOUT = 3.3V unless otherwise noted. (Note 2)
PARAMETER
CONDITIONS
MIN
Input Start-Up Voltage
MAX
0.85
1
UNITS
V
Output Voltage
(Note 6)
3.30
3.40
V
Quiescent Current, VOUT
SHDN = VIN (Note 4)
7
15
µA
Quiescent Current, VIN
SHDN = VIN (Note 4)
0.5
3
µA
Quiescent Current, VIN – Shutdown
SHDN = 0V, VOUT = VIN = 3.3V
Including Switch Leakage
3
10
µA
NMOS Switch On-Resistance
(Note 3)
0.5
Ω
PMOS Switch On-Resistance
(Note 3)
0.8
Ω
0.45
A
l
Peak Current Limit
0.4
SHDN Threshold Voltage
SHDN Input Current
3.20
TYP
0.4
VSHDN = VIN or VOUT
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 LTC3525D is tested under pulsed load conditions such that
TJ ≈ TA. The LTC3525DE 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 LTC3525DI 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. TJ is calculated from the ambient temperature TA and power
dissipation PD according to the following formula:
TJ = TA + (PD • 150°C/W)
0.6
1
V
0.01
1
µA
Note 3: Specification is guaranteed by design and not 100% tested in
production.
Note 4: Current Measurements are performed when the LTC3525D 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.
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3
LTC3525D-3.3
Typical Performance Characteristics
Maximum Output Current vs VIN
(for VOUT to Drop 2.5%)
TA = 25°C unless otherwise noted.
Maximum Startup Load vs VIN
(Resistive Load)
300
No-Load Input Current vs VIN
50
250
45
250
35
150
150
IIN (µA)
LOAD (mA)
200
IOUT (mA)
40
200
100
100
50
10
1.5
2.0
2.5 3.0
VIN (V)
4.0
3.5
4.5
0.5
1.0
1.5
2.0
VIN (V)
2.5
2.5
100
60
1
POWER LOSS
50
40
0.1
VIN = 3V
VIN = 2.4V
VIN = 1.2V
30
20
0.01
CHANGE IN VOUT (%)
EFFICIENCY (%)
EFFICIENCY
POWER LOSS (mW)
10
0.1
1
10
LOAD (mA)
100
0.01
1000
1.5
1.5
1.0
1.0
0.5
COUT = 22µF
0
COUT = 10µF
–0.5
–1.0
10
20
30 40 50
LOAD (mA)
60
0
20
40
60
80 100 120 140 160 180
LOAD (mA)
3525d33 G07
25
COUT = 10µF
COUT = 22µF
Start-Up Delay Coming Out of
Shutdown
120
100
SWITCHING DELAY (µs)
0.20
CHANGE IN VOUT (%)
30
1
LOAD (mA)
–2.5
80
VOUT Variation vs Temperature
(Normalized to 25°C)
0.30
0.1
70
3525d33 G06
35
0.10
–0.00
–0.10
–0.20
3525d33 G12
–0.40
–50
80
60
40
20
–0.30
10
4.5
COUT = 10µF
–1.0
–2.0
0.40
5
–0.5
–1.5
0
4.0
COUT = 22µF
0
–2.0
40
10
0.5
–1.5
–2.5
Light Load Burst Frequency
vs Load
15
3.5
VIN = 2.4V
2.0
3525d33 G04
20
2.5 3.0
VIN (V)
Load Regulation
2.5
VIN = 1.2V
2.0
90
80
2.0
3525d33 G03
Load Regulation
100
1.5
3525d33 G02
Efficiency and Power Loss
vs Load
70
0
1.0
3.0
CHANGE IN VOUT (%)
1.0
0
3525d33 G01
BURST FREQUENCY (kHz)
20
5
0
0.5
4
25
15
50
0
30
–25
0
25
50
75
TEMPERATURE (oC)
100
125
3525d33 G13
0
1.0
1.5
2.0
2.5 3.0
VIN (V)
3.5
4.0
4.5
3525d33 G14
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LTC3525D-3.3
Typical Performance Characteristics
Output Voltage Ripple
TA = 25°C unless otherwise noted.
Output Voltage Ripple
IOUT
5mA
IOUT
5mA
IOUT
40mA
IOUT
40mA
50mV/DIV
IOUT
80mA
50mV/DIV
IOUT
80mA
VIN = 1.2V
COUT = 10µF
50µs/DIV
3525d33 G16
VIN = 1.2V
COUT = 22µF
Output Voltage Ripple
50µs/DIV
3525d33 G17
50mA Load Step Response
IOUT
5mA
IOUT
100mA
50mV/DIV
OUTPUT
RIPPLE
50mV/DIV
LOAD
CURRENT
20mA/DIV
IOUT
190mA
VIN = 2.4V
COUT = 22µF
50µs/DIV
3525d33 G18
VIN = 1.2V
COUT = 22µF
500µs/DIV
3525d33 G21
100mA Load Step Response
OUTPUT
RIPPLE
50mV/DIV
LOAD
CURRENT
50mA/DIV
VIN = 2.4V
COUT = 22µF
500µs/DIV
3525d33 G22
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5
LTC3525D-3.3
Pin Functions
SHDN (Pin 1): Logic-Controlled Shutdown Input. Connect
to a voltage >1V to enable the LTC3525D. Connect to a
voltage <0.4V to disable the LTC3525D and connect VIN
to VOUT through the inductor.
GND (Pins 2, 5): Ground.
VIN (Pin 3): Input Voltage. The LTC3525D is powered from
VIN until VOUT exceeds VIN. Once VOUT is greater than
(VIN + 0.2V typical), it is powered from VOUT. Place a
ceramic bypass capacitor from VIN to GND. A minimum
value of 1µF is recommended.
6
VOUT (Pin 4): Output Voltage Sense and the Output of the
Synchronous Rectifier. Connect the output filter capacitor
from VOUT to GND, close to the IC. A minimum value of
10µF ceramic is recommended. Use 22µF for reduced
output ripple. The pass-through mode feature connects
VOUT to VIN through the inductor when SHDN is <0.4V.
SW (Pin 6): Switch Pin. Connect an inductor from this
pin to VIN. An internal antiringing resistor is connected
across SW and VIN after the inductor current has dropped
to zero to minimize EMI.
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LTC3525D-3.3
Block Diagram
SW
VIN
6
3
VOUT
VSEL
VBEST
WELL
SWITCH
VB
4 VOUT
SHUTDOWN
SHUTDOWN GATE DRIVERS
AND
ANTI-CROSS
CONDUCTION
+
OFFSET
VREF
UVLO
–
ADJUST
VREF
+
–
IPK
UVLO
+
IPK
COMPARATOR
START-UP
LOGIC
IVAL
SHUTDOWN
IVALLEY
COMPARATOR
TSD
–
ADJUST
+
–
THERMAL
SHUTDOWN
OFFSET
+
–
SHDN 1
WAKE
INTEGRATOR
FB
VREF
SLEEP
COMPARATOR
ADJUST
5
2
GND
GND
3525d33 BD
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7
LTC3525D-3.3
Operation
The LTC3525D is a high performance Burst Mode operation
only, synchronous boost converter requiring only three
small external components. Its simplicity and small size
make it a high efficiency alternative to charge pump designs.
It is designed to start up from a single alkaline or nickel
cell, with input voltages as low as 0.85V, or from two or
three cells (or a Li-Ion battery), with voltages as high as
4.5V. Once started, VIN can be as low as 0.5V (depending on load current) and maintain regulation. The output
voltage is preset internally to 3.3V. Peak switch current is
400mA minimum, providing regulation with load currents
up to 150mA, depending on input voltage.
in some applications. Therefore, in applications where
SHDN may be driven above VIN, a resistor divider or other
means must be employed to keep the SHDN voltage below
(VIN + 0.4V) to prevent the possibility of the test mode
being engaged. Please refer to Figure 1 for two possible
implementations.
Synchronous rectification provides high efficiency operation while eliminating the need for an external Schottky
diode.
When the LTC3525D is in shutdown, the internal P‑channel
MOSFET switch is turned on. This allows VIN to be connected to VOUT through the inductor in shutdown, creating
a pass-through mode.
The LTC3525D can maintain regulation with an input
voltage equal to or greater than VOUT. Note, however, that
the synchronous rectifier is not enabled in this mode,
resulting in lower efficiency and reduced output current
capability.
The operating quiescent current is only 7µA typical, allowing the converter to maintain high efficiency at extremely
light loads.
Shutdown
The LTC3525D is shut down by pulling SHDN below 0.4V,
and made active by raising it above 1V. Although SHDN can
be driven above VIN or VOUT (up to the absolute maximum
rating) without damage, the LTC3525D has a proprietary
test mode that may be engaged if SHDN is held in the
range of 0.5V to 1V higher than the greater of VIN or VOUT.
If the test mode is engaged, normal PWM switching action is interrupted, which can cause undesirable operation
LTC3525D-3.3
After the SHDN pin rises, there is a short delay before
switching starts. The delay is 20µs to 120µs, depending
on input voltage (see Typical Performance Characteristics
curve).
Pass-Through Mode
Start-up
A start-up oscillator allows the LTC3525D to start with input
voltages as low as 1V. It remains in start-up mode until
two conditions are met. VOUT must exceed VIN by at least
0.2V typical and either VIN or VOUT must be greater than
1.8V typical.
During start-up, the synchronous rectifier is not enabled,
and the internal P-channel synchronous rectifier acts
as a follower, causing the peak voltage on SW to reach
(VIN + 1V) typical. This limits inrush current by maintaining
control of the inductor current when VOUT is less than VIN.
To reduce power dissipation in the P-channel synchronous
rectifier when the output is shorted, a foldback feature is
incorporated that reduces the peak inductor current when
VIN is more than 1.7V greater than VOUT.
VIN
SHDN
SHDN
VCNTRL
LTC3525D-3.3
3525d33 F01
R
1M
VCNTRL
ZETEX ZC2811E
1M
R > (VCNTRL/(VIN + 0.4) – 1) MΩ
Figure 1
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LTC3525D-3.3
Operation
Normal Operation
Once VOUT has increased more than 0.2V typical above
VIN, and either voltage is above 1.8V, normal operation
begins, with synchronous rectification enabled. In this
mode, the internal N-channel MOSFET connected between SW and GND stays on until the inductor current
reaches a maximum peak value, after which it is turned
off and the P-channel synchronous rectifier is turned
on. It stays on, delivering current to the output, until the
inductor current has dropped below a minimum value at
which point it turns off and the cycle repeats. When the
output voltage reaches its regulated value both switches
are turned off and the LTC3525D goes to sleep, during
which time the output capacitor supplies current to the
load. Once the output voltage drops approximately 9mV
below the regulation value the IC leaves sleep mode and
switching is resumed.
The LTC3525D has been designed for low output voltage
ripple. The output voltage ripple is typically only 20mV
peak-to-peak at light load and 60mV peak-to-peak at
full load using the minimum recommended 10µF output
capacitor. An anti-ring circuit damps any oscillation at the
switch node when the inductor current falls to zero.
Power Adjust Feature
The LTC3525D incorporates a feature that maximizes
efficiency at light load while providing increased power
capability at heavy load by adjusting the peak and valley
of the inductor current as a function of load. Lowering the
peak inductor current to 150mA at light load optimizes
efficiency by reducing conduction losses in the internal
MOSFET switches. As the load increases, the peak inductor
current is automatically increased to a maximum of 400mA.
At intermediate loads, the peak inductor current may vary
from 150mA to 400mA. Figure 2 shows an example of
how the inductor current changes as the load increases.
Please note that output capacitor values greater than 47µF
will result in higher peak currents than necessary at light
load. This will lower the light load efficiency.
The valley of the inductor current is automatically adjusted
as well, to maintain a relatively constant inductor ripple
current. This keeps the switching frequency relatively
constant.
The maximum average load current that can be supported
is given by:
IO(MAX ) =
0.3 • VIN • η
Amps
VO
where η is the efficiency (see Typical Performance
Characteristics).
The “burst” frequency (how often the LTC3525D delivers
a burst of current pulses to the load) is determined by
the internal hysteresis (output voltage ripple), the load
current and the amount of output capacitance. All Burst
Mode operation or hysteretic converters will enter the
audible frequency range when the load is light enough.
However, due to the low peak inductor current at light load,
circuits using the LTC3525D does not typically generate
any audible noise.
INDUCTOR
CURRENT
100mA/DIV
LOAD
CURRENT
50mA/DIV
10µs/DIV
3525d33 F02
Figure 2. Inductor Current Changing as a Function of Load
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9
LTC3525D-3.3
Operation
Component Selection
Inductor values between 4.7µH and 15µH are recommended. In most applications 10µH will yield the best
compromise between size and efficiency. The inductor
should be a low loss ferrite design and must be rated
for peak currents of at least 400mA without saturating.
Inductors with lower DC resistance will improve efficiency.
Note that the inductor value does not have a significant
effect on ripple current, so while lower values will increase
the operating frequency, they do not reduce output voltage ripple.
Some recommended inductor examples are Murata
LQH32C, Coilcraft LPO4812, LPO3310, DO3314, DS1608
and MSS4020, Sumida CDRH2D14 and Taiyo Yuden
NR3015T.
A ceramic input bypass capacitor should be located as
close as possible to the VIN and GND pins of the IC. A
minimum value of 1µF is recommended. If the battery is
more than a few inches away, a bulk tantalum decoupling
cap of at least 10µF is recommended on VIN.
The output capacitor should also be a ceramic, located close
to the VOUT and GND pins. A minimum value of 10µF is
recommended. Increasing the value of the output capacitor
to 22µF will result in lower output ripple. Higher capacitor
values will only offer a small reduction in output ripple,
while reducing light load efficiency by causing the peak
inductor current to increase above its minimum value of
150mA. The input and output capacitors should be X5R
or X7R types, not Y5V.
Table 1. Inductor Vendor Information
SUPPLIER
PHONE
FAX
WEBSITE
Murata
USA: (814) 237-1431
USA: (814) 238-0490
www.murata.com
Coilcraft
(847) 639-6400
(847) 639-1469
www.coilcraft.com
Sumida
USA: (847) 956-0666
USA: (847) 956-0702
www.sumida.com
Taiyo Yuden
(408) 573-4150
(408) 573-4159
www.t-yuden.com
TOKO
(847) 297-0070
(847) 699-7864
www.toko.co.jp/products/en
TDK
(847) 699-2299
(847) 803-6296
www.tdk.com
Würth
(605) 886-4385
(605) 886-4486
www.we-online.com
Table 2. Capacitor Vendor Information
SUPPLIER
PHONE
FAX
WEBSITE
Murata
USA: (814) 237-1431
USA: (814) 238-0490
www.murata.com
Taiyo Yuden
(408) 573-4150
(408) 573-4159
www.t-yuden.com
TDK
(847) 803-6100
(847) 803-6296
www.component.tdk.com
AVX
(803) 448-9411
(803) 448-1943
www.avxcorp.com
SHDN
SHDN
SW
LTC3525D-3.3
VIN
GND
GND
VIN
VOUT
VOUT
3525d33 F03
Figure 3. Recommended Component Placement
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LTC3525D-3.3
Typical Applications
Single Alkaline or NiMH to 3.3V Converter with 1mm Profile
6.8µH*
1V TO 1.6V
3
PASS THROUGH ON
1
2
1µF
*COILCRAFT XPL2010-682ML
**MURATA GRM219R60J106KE191D
LTC3525D-3.3
VIN
SW
SHDN
VOUT
GND
GND
6
VOUT
3.3V
60mA
4
5
10µF**
6.3V
3525d33 TA04
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11
LTC3525D-3.3
Package Description
SC6 Package
6-Lead Plastic SC70
(Reference LTC DWG # 05-08-1638 Rev B)
0.47
MAX
0.65
REF
1.80 – 2.20
(NOTE 4)
1.00 REF
INDEX AREA
(NOTE 6)
1.80 – 2.40 1.15 – 1.35
(NOTE 4)
2.8 BSC 1.8 REF
PIN 1
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.10 – 0.40
0.65 BSC
0.15 – 0.30
6 PLCS (NOTE 3)
0.80 – 1.00
1.00 MAX
0.00 – 0.10
REF
GAUGE PLANE
0.15 BSC
0.26 – 0.46
0.10 – 0.18
(NOTE 3)
SC6 SC70 1205 REV B
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. DETAILS OF THE PIN 1 IDENTIFIER ARE OPTIONAL,
BUT MUST BE LOCATED WITHIN THE INDEX AREA
7. EIAJ PACKAGE REFERENCE IS EIAJ SC-70
8. JEDEC PACKAGE REFERENCE IS MO-203 VARIATION AB
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LTC3525D-3.3
Revision History
REV
DATE
DESCRIPTION
PAGE NUMBER
A
09/10
Updated “Shutdown” section
6
B
04/15
Added table to reference other LTC3525 family parts
1
Changed Operating Temperature Range to Operating Junction Temerature Range and changed the Operating
Temperature Range from 85°C to 125°C in the Absolute Maximum Ratings
2
Updated Order Information table
2
Changed Operating Temperature Range to Operating Junction Temperature Range and added Note 2 to the Electrical
Characteristics section
3
Updated Note 2 for addition of I Grade
3
Updated VOUT Variation vs Temperature curve
4
Updated Inductor Vendor Information in Table 1
10
Updated Inductor information
11
Added Typical Application circuit
14
Modified Related Parts table
14
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Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its
circuits as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LTC3525D3.3
13
LTC3525D-3.3
Typical Application
2-Alkaline or NiMH to 3.3V
10µH*
1.8V TO 3.2V
PASS THROUGH ON
3
1
2
1µF
LTC3525D-3.3
VIN
SW
SHDN
VOUT
GND
GND
*SUMIDA 252012CDMCQDS-100MC
6
VOUT
3.3V
140mA
4
5
10µF
3525d33 TA05
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
LTC3400/LTC3400B
600mA (ISW), 1.2MHz, Synchronous Step-Up DC/DC
Converter
92% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5V,
IQ = 19µA/300µA, ISD < 1µA, ThinSOT Package
LTC3401
1A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter
97% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5.5V,
IQ = 38µA, ISD < 1µA, MS Package
LTC3402
2A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter
97% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5.5V,
IQ = 38µA, ISD < 1µA, MS Package
LTC3421
3A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter
with Output Disconnect
95% Efficiency, VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V,
IQ = 12µA, ISD < 1µA, QFN-24 Package
LTC3429/LTC3429B
600mA, 500kHz Single/Dual Cell Micropower Synchronous
Boost Converter with Output Disconnect
95% Efficiency, VIN: 1V to 4.5V, VOUT(MAX) = 5V,
IQ = 20µA, ISD < 1µA, SC70 Package
LTC3458
1.4A (ISW), 1.5MHz, Synchronous Step-Up DC/DC Converter
with Output Disconnect
VIN: 1.5V to 6V, VOUT(MAX) = 7.5V, ISD < 1µA,
3mm × 4mm DFN Package
LTC3458L
1.7A (ISW), 1.5MHz, Synchronous Step-Up DC/DC Converter
with Output Disconnect
VIN: 1.5V to 6V, VOUT(MAX) = 6V, ISD <1 µA,
3mm × 4mm DFN Package
LTC3459
60mA, 10V Micropower Synchronous Boost Converter
95% Efficiency, VIN: 1.5V to 6V, VOUT(MAX) = 10V,
IQ =10µA, ISD < 1µA, ThinSOT Package
LT3464
85mA (ISW), High Efficiency Step-Up DC/DC Converter
with Integrated Schottky and PNP Disconnect
VIN: 2.3V to 10V, VOUT(MAX) = 34V, IQ = 25µA,
ISD < 1µA, ThinSOT Package
LT3427
500mA (ISW), 1.2MHz, Step-Up DC/DC Converter with Output VIN: 1.8V to 5V, VOUT(MAX) = 5V, ISD < 1µA,
Disconnect
2mm × 2mm DFN Package
LTC3525-3/LTC3525-3.3/ 400mA Synchronous Step-Up DC/DC Converter with Output
LTC3525-5
Disconnect
VIN: 0.5V to 4.5V, VOUT(MAX) = 5V, IQ = 7µA, ISD < 1µA,
SC70 Package
LTC3526/LTC3526B
500mA. 1MHz, Synchronous Step-Up DC/DC Converter
with Output Disconnect
VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 9µA, ISD < 1µA,
2mm × 2mm DFN-6 Package
LTC3528/LTC3528B
1A, 1MHz Synchronous Step-Up DC/DC Converter with
Output Disconnect
94% Efficiency, VIN Start-Up Voltage: 700mV, VOUT(MAX) = 5.25V,
IQ = 12µA, ISD < 1 µA, 2mm × 3mm DFN Package
LTC3529
1.5A, 1.5MHz, Synchronous Step-Up DC/DC Converter
95% Efficiency, VIN: 1.8V to 5.25V, VOUT(MAX) = 5.15V, ISD < 1µA,
2mm × 3mm DFN Package
LTC3539/LTC3539-2
2A, 1MHz/2MHz Synchronous Step-Up DC/DC Converter
94% Efficiency, VIN Start-Up Voltage: 700mV, VOUT(MAX) = 5.25V,
IQ = 12µA, ISD < 1 µA, 2mm × 3mm DFN Package
14
3525d33fb
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTC3525D3.3
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LTC3525D3.3
LT 0415 REV B • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2006