LTC3537EUD#PBF
更新时间：2024-09-18 17:52:29
品牌：Linear
描述：LTC3537 - 2.2 MHz, 600mA Synchronous Step-Up DC/DC Converter and 100mA LDO; Package: QFN; Pins: 16; Temperature Range: -40°C to 85°C
概述
规格参数
数据手册LTC3537EUD#PBF 概述
LTC3537 - 2.2 MHz, 600mA Synchronous Step-Up DC/DC Converter and 100mA LDO; Package: QFN; Pins: 16; Temperature Range: -40°C to 85°C 稳压芯片 开关式稳压器或控制器
LTC3537EUD#PBF 规格参数
| 是否Rohs认证： | 符合 | 生命周期： | Transferred |
| 零件包装代码： | QFN | 包装说明： | HVQCCN, LCC16,.12SQ,20 |
| 针数： | 16 | Reach Compliance Code： | compliant |
| ECCN代码： | EAR99 | HTS代码： | 8542.39.00.01 |
| 风险等级： | 3.17 | 其他特性： | ALSO OPERATES IN ADJUSTABLE MODE FROM 0.6V TO 5V; ALSO OPERATES AS LDO REGULATOR |
| 模拟集成电路 - 其他类型： | SWITCHING REGULATOR | 控制模式： | CURRENT-MODE |
| 控制技术： | PULSE WIDTH MODULATION | 最大输入电压： | 5 V |
| 最小输入电压： | 0.68 V | 标称输入电压： | 1.2 V |
| JESD-30 代码： | S-PQCC-N16 | JESD-609代码： | e3 |
| 长度： | 3 mm | 湿度敏感等级： | 1 |
| 功能数量： | 1 | 端子数量： | 16 |
| 最高工作温度： | 85 °C | 最低工作温度： | |
| 最大输出电流： | 0.75 A | 封装主体材料： | PLASTIC/EPOXY |
| 封装代码： | HVQCCN | 封装等效代码： | LCC16,.12SQ,20 |
| 封装形状： | SQUARE | 封装形式： | CHIP CARRIER, HEAT SINK/SLUG, VERY THIN PROFILE |
| 峰值回流温度（摄氏度）： | 260 | 认证状态： | Not Qualified |
| 座面最大高度： | 0.8 mm | 子类别： | Switching Regulator or Controllers |
| 表面贴装： | YES | 切换器配置： | BOOST |
| 最大切换频率： | 2400 kHz | 技术： | CMOS |
| 温度等级： | OTHER | 端子面层： | Matte Tin (Sn) |
| 端子形式： | NO LEAD | 端子节距： | 0.5 mm |
| 端子位置： | QUAD | 处于峰值回流温度下的最长时间： | 30 |
| 宽度： | 3 mm | Base Number Matches： | 1 |
LTC3537EUD#PBF 数据手册
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PDF下载LTC3537
2.2 MHz, 600mA
Synchronous Step-Up DC/DC
Converter and 100mA LDO
FEATURES
DESCRIPTION
TheLTC®3537combinesahighefficiency,2.2MHzstep-up
DC/DCconverterwithanindependent100mAlowdropout
regulator(LDO).Thestep-upconverterstartsfromaninput
voltage as low as 0.68V and contains an internal 0.4Ω
switch and a 0.6Ω synchronous rectifier that disconnects
from the output when disabled in shutdown.
n
High Efficiency Step-Up DC/DC Converter and LDO
Step-Up
n
V : 0.68V to 5V, V : 1.5V to 5.25V
OUT
2.2MHz Fixed Frequency Operation
Synchronous Rectifier with Output Disconnect
Burst Mode Operation (Pin Selectable)
IN
OUT
I
: 100mA at 3.3V, V >0.8V
IN
n
n
n
A switching frequency of 2.2MHz minimizes solution
footprint by allowing the use of tiny, low profile inductors
and ceramic capacitors. The current mode PWM design
is internally compensated, reducing external parts count.
Fixed frequency switching is maintained until a light load
current is sensed, at which point Burst Mode® operation is
engaged to maximize efficiency. For low noise operation,
Burst Mode Operation can be disabled. Anti-ring circuitry
reduces EMI by damping the inductor in discontinuous
mode. Additional features include a low shutdown current
of under 1μA and thermal overload protection.
Linear LDO Regulator
n
V : 1.8V to 5.5V, V : 0.6V to 5V
OUT
100mV Dropout Voltage at 50mA
24dB Ripple Rejection at f
IN
OUT
I
: 100mA
n
n
SW
Combined
n
Power Good Indicators
n
n
n
Low-Battery Comparator
30μA I
Q
Low Profile 3mm × 3mm × 0.75mm Package
The integrated LDO regulator provides a very low noise,
programmable low dropout supply.
L, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIONS
n
Wireless Microphones
n
Portable Medical instruments
n
Noise Cancelling/Portable Headsets
n
RF and Audio Power
TYPICAL APPLICATION
Efficiency and Power Loss
vs Load Current
100
90
80
70
60
50
40
30
20
10
0
1000
100
10
2.2μH
R6
V
SW
OUTB
V
V
OUTB
INB
665k
3.3V
EFFICIENCY
33pF
R2
LTC3537
LBI
LBO
V
ALKALINE
0.8V
INL
+
1.74M
10μF
R5
1.0M
TO
FBB
PGDB
PGDL
ENLDO
ENBST
MODE
1.6V
V
OLDO
V
OLDO
1μF
1
3V
POWER LOSS
R4
OFF ON
PWM BURST
2.05M
1μF
FBL
0.1
0.01
R1
1M
R3
SGND PGND
511k
V
, MODE = 1.8V
INB
10
LOAD CURRENT (mA)
0.01
0.1
1
100
1000
3537 TA01a
3537 TA01b
3537fd
1
LTC3537
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
TOP VIEW
V
and V Voltage................................... –0.3V to 6V
INL
INB
SW DC Voltage............................................. –0.3V to 6V
SW Pulsed (<100ns) Voltage ....................... –0.3V to 7V
FBB, FBL, PGDB, PGDL Voltage ................... –0.3V to 6V
MODE, ENBST, ENLDO Voltage ................... –0.3V to 6V
LBI and LBO Voltage.................................... –0.3V to 6V
16 15 14 13
MODE
LBI
1
2
3
4
12
11
10
9
V
V
INL
OLDO
17
SGND
FBL
FBB
V
INB
V
, V
............................................... –0.3V to 6V
OUTB OLDO
5
6
7
8
Operating Temperature (Notes 2, 5)......... –40°C to 85°C
Junction Temperature ........................................... 125°C
Storage Temperature Range................... –65°C to 125°C
UD PACKAGE
16-LEAD (3mm × 3mm) PLASTIC QFN
T
= 125°C, θ = 68°C/W (Note 6)
JA
JMAX
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
16-Lead (3mm × 3mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 85°C
LTC3537EUD#PBF
LTC3537EUD#TRPBF
LDBD
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/
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VINB = 1.2V, VOUTB = 3.3V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Boost Converter
V
V
V
Minimum Start-Up Voltage
Output Voltage Range
Feedback Voltage
I
= 1mA
0.68
0.8
5.25
1.240
50
V
V
INMIN
OUTB
FBB
LOAD
l
l
1.5
1.179
1.21
1
V
I
I
Feedback Input Current
Quiescent Current - Shutdown
nA
μA
FBB
V
V
= V = 0V, Not Including SW Leakage,
ENLDO
= 0V
0.02
1
QSHDN
ENBST
OUTB
I
I
Quiescent Current - Active
Quiescent Current - Burst
Measured on V
ENLDO
, Nonswitching, MODE = 1.2V,
, FBB >1.24V, MODE = 1.2V,
300
15
500
μA
μA
QACTIVE
OUTB
V
= 0V
Measured on V
QBURST
OUTB
V
V
V
= 0V
ENLDO
I
I
NMOS Switch Leakage Current
PMOS Switch Leakage Current
= 5V
0.1
0.1
5
μA
μA
NLEAK
PLEAK
SW
SW
= 5V, V
= 0V
10
OUTB
3537fd
2
LTC3537
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2) VINB = 1.2V, VOUTB = 3.3V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
R
NMOS Switch On Resistance
V
V
V
= 1.8V
= 3.3V
= 5V
0.8
0.4
0.3
Ω
Ω
Ω
NMOS
PMOS
OUTB
OUTB
OUTB
R
PMOS Switch On Resistance
V
OUTB
V
OUTB
V
OUTB
= 1.8V
= 3.3V
= 5V
1
0.6
0.4
Ω
Ω
Ω
l
I
t
NMOS Current Limit
(Note 4)
(Note 3)
600
87
750
40
mA
ns
LIM
Current Limit Delay Time to
Output
LIMDELAY
l
l
l
Max Duty Cycle
V
V
= 1.15V
= 1.3V
92
%
%
FBB
Min Duty Cycle
0
FBB
f
Switching Frequency
ENBST Input High Voltage
ENBST Input Low Voltage
ENBST Input Current
MODE Input High Voltage
MODE Input Low Voltage
MODE Input Current
Soft-Start Time
2
2.2
2.4
MHz
V
SW
V
V
0.8
ENBSTH
ENBSTL
ENBSTIN
0.3
0.3
V
I
V
V
= 5.5V
= 5.5V
1.5
μA
V
ENBST
V
V
0.8
MODEH
MODEL
MODEIN
SS
V
I
t
1.5
0.5
553
35
μA
ms
mV
mV
nA
mV
μA
mV
μA
MODE
V
LBI Feedback Voltage
LBI Hysteresis Voltage
LBI Input Current
Falling Threshold
530
575
50
1
FBLBI
I
V
LBI
= 1V
10
LBIIN
V
LBO Voltage Low
I
= 5mA
= 5.5V
200
0.01
200
0.01
94
LBOLOW
LBO
I
LBO Leakage Current
PGDB Voltage Low
PGDB Leakage Current
PGDB Trip Point Voltage
PGDB Hysteresis
V
LBO
LBOLEAK
V
I
= 5mA
= 5.5V
PGDBLOW
PGDB
I
V
V
1
PGDBLEAK
PGDB
Rising
% V
OUTB
FBB
6
%
The ldenotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2)
VINL = 3.3V, VOLDO = 3V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
LDO Regulator
V
V
Input Voltage Range
Output Voltage Range
Max Output Current
Feedback Voltage
Line Regulation
1.8
5.5
5
V
V
INL
I
= 100mA
V
FBL
OLDO
OUTMAX
LOAD
l
l
I
100
590
mA
mV
%
V
600
0.1
0.4
100
610
FBL
V
= 1.8V to 5.5V
INL
Load Regulation
I
= 10mA to 90mA
%
LOAD
V
Dropout Voltage
I = 50mA
O
mV
DROPOUT
3537fd
3
LTC3537
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2) VINL = 3.3V, VOLDO = 3V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
24
MAX
UNITS
dB
PSRR
Ripple Rejection
f = 2.2MHz at I
= 100mA (Note 3)
LOAD
l
I
Short Circuit Current Limit
ENLDO Input High Voltage
ENLDO Input Low Voltage
ENLDO Input Current
PGDL Voltage Low
PGDL Leakage Current
PGDL Trip Point
V
= 0V
110
0.8
150
mA
V
SHORT
OLDO
V
V
ENLDOH
ENLDOL
ENLDO
0.3
1
V
I
V
= 5.5V
= 5.5V
1.5
200
0.01
96
μA
ENLDO
V
I
= 5mA
mV
μA
PGDLLOW
PGDLLEAK
PGDL
I
V
V
PGDL
Rising
% V
OLDO
FBL
PGDL Hysteresis
3
%
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 LTC3537 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 4: Current measurements are made when the output 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 result in device degradation or failure.
Note 6: Failure to solder the exposed backside of the package to the PC
board ground plane will result in a thermal resistance much higher than
68°C/W.
Note 3: Specification is guaranteed by design and not 100% tested in
production.
3537fd
4
LTC3537
TA = 25°C unless otherwise noted.
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Load Current and
VINB for VOUTB = 1.8V
Efficiency vs Load Current and
VINB for VOUTB = 3.3V
No-Load Input Current vs VINB
100
90
80
70
60
50
40
30
20
10
0
1000
100
10
180
160
140
120
100
80
100
90
80
70
60
50
40
30
20
10
0
1000
100
10
V
= 5V
OUTB
OUTB
OUTB
OUTB
V
V
V
= 3.3V
= 2.5V
= 1.8V
V
V
V
V
= 1.2V
= 1.8V
= 2.4V
= 2.8V
INB
INB
INB
INB
1
1
V
V
V
= 1V
= 1.2V
= 1.5V
INB
INB
INB
60
PLOSS AT V = 1.2V
40
INB
0.1
0.1
0.01
PLOSS AT V = 1V
INB
PLOSS AT V = 1.8V
INB
PLOSS AT V = 1.2V
20
INB
PLOSS AT V = 2.4V
INB
PLOSS AT V = 1.5V
INB
PLOSS AT V = 2.8V
INB
0.01
0
0.6 1.2 1.8 2.4
3
3.6 4.2 4.8
0.01
0.1
1
10
100
1000
0.01
0.1
1
10
100
1000
V
(V)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
INB
3537 G02
3537 G01
3537 G03
Efficiency vs Load Current and
VINB for VOUTB = 5V
Minimum Load Resistance During
Start-Up vs VINB
Maximum Output Current vs VINB
100
90
80
70
60
50
40
30
20
10
0
1000
100
10
1000
900
800
700
600
500
400
300
200
100
0
1000
100
10
V
= 5V
OUTB
V
= 3.3V
OUTB
V
V
V
V
= 1.2V
INB
INB
INB
INB
INB
INB
= 2.4V
= 3.6V
= 4.2V
1
V
= 2.5V
OUTB
PLOSS AT V = 1.2V
V
= 1.8V
OUTB
0.1
PLOSS AT V = 2.4V
PLOSS AT V = 3.6V
INB
INB
PLOSS AT V = 4.2V
0.01
0.01
0.1
1
10
100
1000
0.5
1
1.5
2
2.5
(V)
3
3.5
4
4.5
0.8 0.9
1
1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
LOAD CURRENT (mA)
V
V
(V)
INB
INB
3537 G04
3537 G05
3537 G06
Burst Mode Threshold Current
vs VINB
Burst Mode Threshold Current
vs VINB
Start-Up Delay Time vs VINB
60
50
40
30
20
10
0
45
40
35
30
25
20
15
10
5
50
45
40
35
30
25
20
15
10
5
V
C
= 1.8V
= 10μF
V
C
= 2.5V
= 10μF
OUTB
OUTB
OUTB
OUTB
L = 2.2μH
L = 2.2μH
LEAVE BURST
LEAVE BURST
ENTER BURST
ENTER BURST
0
0
1
1.5
2
2.5
3
3.5
4
4.5
5
0.8
1
1.1
(V)
1.2
1.3
1.4
0.8
1.2
1.4
(V)
1.6
1.8
2
3537 G09
0.9
1
V
(V)
V
V
INB
INB
INB
3537 G07
3537 G08
3537fd
5
LTC3537
TA = 25°C unless otherwise noted.
TYPICAL PERFORMANCE CHARACTERISTICS
Burst Mode Threshold Current
vs VINB
Burst Mode Threshold Current
vs VINB
Oscillator Frequency Change
vs VOUTB
1
0
60
50
40
30
20
10
0
180
160
140
120
100
80
V
C
= 3.3V
= 10μF
V
C
= 5V
OUTB
OUTB
OUTB
OUTB
NORMALIZED TO 3.3V
= 10μF
L = 2.2μH
L = 2.2μH
–1
–2
–3
–4
–5
–6
LEAVE BURST
ENTER BURST
LEAVE BURST
60
40
ENTER BURST
20
0
1.5
2
2.5
3
3.5
(V)
4
4.5
5
0.8
1.2 1.4 1.6 1.8
(V)
2
2.2 2.4
0.9 1.4 1.9 2.4 2.9 3.4 3.9 4.4
(V)
1
V
V
V
INB
OUTB
INB
3537 G12
3537 G10
3537 G11
Oscillator Frequency Change vs
Temperature
RDS(ON) vs VOUTB
RDS(ON) Change vs Temperature
1
0
30
20
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
NORMALIZED TO 25°C
NORMALIZED TO 25°C
10
–1
–2
–3
–4
PMOS
0
PMOS
NMOS
–10
–20
–30
NMOS
2.5
–40 –20
0
20
40
60
80
–40 –20
0
20
40
60
80
1.5
2
3
3.5
(V)
4
4.5
5
TEMPERATURE (°C)
TEMPERATURE (°C)
V
OUTB
3537 G14
3537 G15
3537 G13
Feedback Voltage Change
vs Temperature
Burst Mode Quiescent Current
vs VOUTB
Start-Up Voltage vs Temperature
0.05
0.00
0.80
0.75
0.70
0.65
0.60
0.55
0.50
60
50
40
30
20
10
NORMALIZED TO 20°C
V
AND V
FBL
FBB
–0.10
–0.15
–0.20
–0.25
–0.30
V
= 1.2V
INB
ENLDO = HIGH
–40 –20
0
20
40
60
80
–40 –20
0
20
40
60
80
1.8
2.3
2.8
3.3
3.8
(V)
4.3
4.8
TEMPERATURE (°C)
TEMPERATURE (°C)
V
OUTB
3537 G16
3537 G17
3537 G18
3537fd
6
LTC3537
TA = 25°C unless otherwise noted.
TYPICAL PERFORMANCE CHARACTERISTICS
Fixed Frequency Switching
Waveform and VOUTB Ripple
VOUTB and IINB During Soft-Start
Burst Mode Waveforms
ENBST
V
OUTB
20mV/DIV
SW
2V/DIV
V
OUTB
2V/DIV
V
OUTB
I
L
20mV/
DIV
10mA/DIV
I
VINB
200mA/
DIV
3537 G21
3537 G20
V
= 1.2V
3537 G19
INB
V
V
C
= 2.4V
100μs/DIV
200ns/DIV
INB
10μs/DIV
V
V
C
= 2.4V
INB
V
C
= 3.3V
OUTB
OUTB
LOAD
= 3.3V
= 10μF
OUTB
OUTB
= 3.3V
OUTB
OUTB
= 4.7μF
= 10mA
= 4.7μF
I
Load Current Step Response
(Fixed Frequency)
Load Current Step Response
(from Burst Mode Operation)
Load Current Step Response
(Fixed Frequency)
V
V
V
OUTB
OUTB
OUTB
100mV/
DIV
100mV/
DIV
100mV/
DIV
I
LOAD
I
I
LOAD
100mA/
DIV
LOAD
100mA/
DIV
100mA/
DIV
3537 G24
3537 G23
3537 G22
V
V
C
= 3.6V
100μs/DIV
V
V
C
= 2.4V
INB
V
V
C
= 2.4V
100μs/DIV
100μs/DIV
INB
INB
= 5V
= 3.3V
OUTB
OUTB
= 3.3V
OUTB
OUTB
OUTB
OUTB
= 4.7μF
= 4.7μF
= 4.7μF
LDO Dropout Voltage vs
Load Current
LDO Input Ripple Rejection vs
Frequency
Load Current Step Response
(from Burst Mode Operation)
140
120
100
80
60
50
40
30
20
10
0
V
V
C
= 3.3V
INL
= 3V
OLDO
OLDO
LOAD
= 4.7μF
= 50mA
I
V
OUTB
100mV/
DIV
60
I
LOAD
40
100mA/
DIV
20
0
3537 G25
V
V
C
= 3.6V
100μs/DIV
0
10 20 30 40 50 60 70 80 90 100
INB
0.01
0.1
1
10
100
= 5V
OUTB
OUTB
LOAD CURRENT (mA)
FREQUENCY (kHz)
= 4.7μF
3537 G26
3537 G29
3537fd
7
LTC3537
TA = 25°C unless otherwise noted.
LDO Load Current Step Response
TYPICAL PERFORMANCE CHARACTERISTICS
LDO Current Limit vs Temperature
7
NORMALIZED TO 25°C
6
5
V
4
3
OLDO
100mV/
DIV
2
1
I
LOAD
100mA/
DIV
0
–1
–2
3537 G31
–40
–20
0
20
40
60
80
100μs/DIV
V
V
C
= 3.3V
INL
TEMPERATURE (°C)
= 3V
OLDO
3537 G30
= 1μF
OUT
LDO Load Current Step Response
LDO Load Current Step Response
V
V
OLDO
100mV/
DIV
OLDO
100mV/
DIV
I
I
LOAD
LOAD
100mA/
DIV
100mA/
DIV
3537 G32
3537 G33
V
V
C
= 5V
100μs/DIV
V
V
C
= 5V
100μs/DIV
INL
OLDO
INL
OLDO
= 3V
= 1μF
= 1.8V
= 1μF
OUT
OUT
3537fd
8
LTC3537
PIN FUNCTIONS
MODE (Pin 1): Logic Controlled Input for the Auto-Burst
Mode Feature.
FBB (Pin 9): Feedback Input to the g Error Amplifier
m
of the Boost Converter. Connect resistor divider tap to
this pin. The output voltage can be adjusted from 1.5V
to 5.25V by:
MODE = High: PWM operation with Burst Mode
Operation
MODE = Low: PWM operation only
V
= 1.21V • [1 + (R2/R1)]
OUTB
LBI(Pin2):Low-BatteryComparatorNon-InvertingInput.
FBL (Pin 10): Feedback Input to the g Error Amplifier of
m
(Comparator enabled with ENBST or ENLDO)
theLDO.Connectresistordividertaptothispin.Theoutput
voltage can be adjusted from 0.6V (typical) to 5V by:
SGND (Pin 3): Signal Ground. Provide a short direct PCB
path between GND and the (–) side of the input and output
capacitors.
V
OLDO
= 0.6V • [1 + (R4/R3)]
V
OLDO
(Pin 11): LDO Regulator Output. PCB trace from
OLDO
V
V
(Pin 4): Input Supply for the Step-Up Converter.
to the output filter capacitor (1μF minimum) should
INB
Connect a minimum of 1μF ceramic decoupling capacitor
be as short and as wide as possible.
from this pin to ground.
V
V
(Pin 12): Input Supply for the LDO Regulator.
INL
PGDB (Pin 5): Power Good Indicator for the Boost Con-
(Pin 13): Output Voltage Sense Input and Drain
OUTB
verter. This is an open-drain output that sinks current
of the Internal Synchronous Rectifier. PCB trace length
when V
is less than 94% of the programmed voltage.
OUTB
from V
to the output filter capacitor (4.7μF minimum)
OUTB
ENBST (Pin 6): Logic controlled shutdown input for the
boost converter.
should be as short and wide as possible.
SW (Pin 14): Switch Pin. Connect the inductor between
ENBST = High: Normal operation
ENBST = Low: Shutdown
SW and V . Keep these PCB trace lengths as short and
INB
wideaspossibletoreduceEMI.Iftheinductorcurrentfalls
to zero or ENBST is low, an internal anti-ringing switch is
PGDL (Pin 7): Power Good Indicator for the LDO Regula-
connected from SW to V to minimize EMI.
INB
tor. This is an open-drain output that sinks current when
V
is less than 96% of the programmed voltage.
PGND (Pin 15): Power Ground. Provide a short direct
PCB path between GND and the (–) side of the input and
output capacitors.
OLDO
ENLDO (Pin 8): Logic Controlled Shutdown Input for the
LDO Regulator.
LBO (Pin 16): Low-Battery Comparator Output. (Open-
Drain)
ENLDO = High: Normal operation
ENLDO = Low: Shutdown
GND (Exposed Pad Pin 17): Power Ground. The Exposed
Pad must be soldered to the PCB.
3537fd
9
LTC3537
BLOCK DIAGRAM
SW
V
INB
V
OUT
WELL
SWITCH
V
BEST
V
BEST
V
OUTB
R2
R1
GATE DRIVERS
AND
ANTI-CROSS
CONDUCTION
FBB
SHUTDOWN
SHUTDOWN
ENBST
ENLDO
Σ
–
+
+
–
1.21V
REF
SLOPE
COMPENSATION
V
V
V
REF
REF
UVLO
STARTUP
LOGIC
MODE
CONTROL
2.2MHz
OSC
WELL
SWITCH
CLAMP
THERMAL
SHUTDOWN
V
INL
+
1.14V
V
OLDO
PGDB
PGDL
R4
R3
–
FBB
GATE
DRIVER
+
–
+
–
–
0.58V
FBL
0.6V
0.55V
+
FBL
LBI
LBO
MODE
SGND
PGND
3537 BD
V
IN
R6
R5
3537fd
10
LTC3537
OPERATION
The LTC3537 is a 2.2MHz synchronous step-up (boost)
converter and LDO regulator housed in a 16-lead 3mm
× 3mm QFN package. Included with the ability to start
up and operate from inputs less than 0.7V, the LTC3537
features fixed frequency, current mode PWM control for
exceptional line and load regulation.
LOW NOISE FIXED FREQUENCY OPERATION
Soft-Start
The LTC3537 contains internal circuitry to provide soft-
start operation. The soft-start circuitry slowly ramps the
peakinductorcurrentfromzerotoitspeakvalueof750mA
(typical) in approximately 0.5ms, allowing start-up into
heavy loads. The soft-start circuitry is reset in the event
of a shutdown command or a thermal shutdown.
The current mode architecture with adaptive slope com-
pensation provides excellent transient load response,
requiring minimal output filtering. Internal soft-start and
loop compensation simplifies the design process while
minimizingthenumberofexternalcomponents.Withitslow
Oscillator
R
DS(ON)
and low gate charge internal N-channel MOSFET
An internal oscillator sets the switching frequency to
2.2MHz.
switch and P-channel MOSFET synchronous rectifier, the
LTC3537 achieves high efficiency over a wide range of
load currents. Automatic Burst Mode operation maintains
high efficiency at very light loads, reducing the quiescent
current to just 30μA. Operation can be best understood
by referring to the Block Diagram.
Shutdown
Shutdown of the boost converter is accomplished by
pulling ENBST below 0.3V and enabled by pulling ENBST
above 0.8V. Note that ENBST can be driven above V or
INB
V
, as long as it is limited to less than the absolute
OUTB
maximum rating.
LOW VOLTAGE START-UP
The LTC3537 step-up converter includes an independent
start-up oscillator designed to operate at an input voltage
of 0.68V (typical). Soft-start and inrush current limiting
are provided during start-up, as well as normal mode.
Boost Error Amplifier
The non-inverting input of the transconductance error
amplifier is internally connected to the 1.2V reference
and the inverting input is connected to FBB. Clamps limit
the minimum and maximum error amp output voltage for
improvedlarge-signaltransientresponse.Powerconverter
controlloopcompensationisprovidedinternally.Anexter-
When either V or V
exceeds 1.4V typical, the IC
OUTB
INB
enters normal operating mode. When the output voltage
exceedstheinputby0.24V,theICpowersitselffromV
OUTB
instead of V . At this point the internal circuitry has no
INB
nalresistivevoltagedividerfromV
the output voltage via FBB from 1.5V to 5.25V.
togroundprograms
OUTB
dependency on the V
input voltage, eliminating the
INB
requirement for a large input capacitor. The input voltage
can drop as low as 0.5V after start-up is achieved. The
limiting factor for the application becomes the availability
of the power source to supply sufficient energy to the
output at low voltages, and maximum duty cycle, which
is clamped at 92% typical. Note that at low input voltages,
small voltage drops due to series resistance become
critical, and greatly limit the power delivery capability of
the converter.
⎛
⎞
⎟
⎠
R2
R1
VOUTB = 1.21V 1+
⎜
⎝
Boost Current Sensing
Losslesscurrentsensingconvertsthepeakcurrentsignalof
theN-channelMOSFETswitchintoavoltagethatissummed
with the internal slope compensation. The summed signal
is compared to the error amplifier output to provide a peak
current control command for the PWM.
3537fd
11
LTC3537
OPERATION
Boost Current Limit
Thermal Overload Protection
The current limit comparator shuts off the N-channel
MOSFET switch once its threshold is reached. The cur-
rent limit comparator delay to output is typically 40ns.
Peak switch current is limited to approximately 750mA,
If the die temperature exceeds 160°C typical, the LTC3537
boost converter will shut down. All switches will be off
and the soft-start capacitor will be discharged. The boost
converter will be enabled when the die temperature drops
by approximately 15°C.
independent of input or output voltage, unless V
falls
OUTB
below 0.8V, in which case the current limit is cut in half.
BOOST BURST MODE OPERATION
Boost Zero Current Comparator
When enabled (MODE pin high), the LTC3537 will auto-
matically enter Burst Mode operation at light load current
and return to fixed frequency PWM mode when the load
increases.RefertotheTypicalPerformanceCharacteristics
The zero current comparator monitors the inductor cur-
rent to the output and shuts off the synchronous rectifier
when this current reduces to approximately 30mA. This
prevents the inductor current from reversing in polarity,
improving efficiency at light loads.
to see the Burst Mode Threshold Current vs V . The
INB
load current at which Burst Mode operation is entered can
be changed by adjusting the inductor value. Raising the
inductor value will lower the load current at which Burst
Mode operation is entered.
Boost Synchronous Rectifier
To control inrush current and to prevent the inductor cur-
rent from running away when V
is close to V , the
OUTB
INB
In Burst Mode operation, the LTC3537 still switches at a
fixed frequency of 2.2MHz, using the same error amplifier
and loop compensation for peak current mode control.
This control method eliminates any output transient when
switching between modes. In Burst Mode operation, en-
ergy is delivered to the output until it reaches the nominal
voltage regulation value, then the LTC3537 transitions to
sleep mode where the outputs are off and the LTC3537
P-channel MOSFET synchronous rectifier is only enabled
when V > (V + 0.24V).
OUTB
INB
Boost Anti-Ringing Control
The anti-ringing control connects a resistor across the
inductor to prevent high frequency ringing on the SW pin
during discontinuous current mode operation. Although
the ringing of the resonant circuit formed by L and C
SW
consumes only 30μA of quiescent current from V
OUTB
(capacitance on SW pin) is low energy, it can cause EMI
including the current required to keep the LDO enabled.
When the output voltage droops slightly, switching re-
sumes. This maximizes efficiency at very light loads by
minimizing switching and quiescent losses. Burst Mode
output voltage ripple, which is typically 1% peak-to-peak,
can be reduced by using more output capacitance (10μF
or greater), or with a small capacitor (10pF to 50pF) con-
radiation.
Boost Output Disconnect
The LTC3537 is designed to allow true output disconnect
by eliminating body diode conduction of the internal P-
channel MOSFET synchronous rectifier. This allows V
OUTB
to go to zero volts during shutdown, drawing no current
from the input source. It also allows inrush current limit-
ing at turn-on, minimizing surge currents seen by the
input supply. Note that to obtain the advantages of output
disconnect, there cannot be an external Schottky diode
nected between V
and FBB.
OUTB
As the load current increases, the LTC3537 will automati-
cally leave Burst Mode operation. Note that larger output
capacitorvaluesmaycausethistransitiontooccuratlighter
loads.OncetheLTC3537hasleftBurstModeoperationand
returned to normal operation, it will remain there until the
output load is reduced below the burst threshold.
connected between the SW pin and V
. The output
OUTB
to be pulled high,
disconnect feature also allows V
OUTB
above the nominal regulation voltage, without any reverse
current into the power source connected to V
.
INB
3537fd
12
LTC3537
OPERATION
BurstModeoperationisinhibitedduringstart-upandsoft-
LDO Current Sensing and Limiting
start and until V
is at least 0.24V greater than V
.
OUTB
INB
Current is sensed across an internal resistor. The guaran-
teed minimum output current is 100mA.
The LTC3537 will operate at a continuous PWM frequency
of2.2MHzbyconnectingMODEtoGND.Atverylightloads,
the LTC3537 will exhibit pulse-skip operation.
LOW-BATTERY INDICATOR
The LTC3537 includes a low-battery comparator. The non-
inverting input of the comparator is internally connected
to a 0.58V reference and the inverting input is connected
Single Cell to 5V Step-Up Applications
Due to the high inductor current slew rate in applications
boosting to 5V from a single-cell (alkaline, NiCd or NiMH),
theLTC3537maynotenterBurstModeoperationforinput
voltages less than 1.2V. Refer to the Typical Performance
Characteristics curves for the Burst Mode thresholds for
different input and output voltages.
to LBI. An external resistive voltage divider from V to
INL
ground programs the threshold voltage. When the volt-
age at LBI drops below 0.58V, the open-drain N-channel
MOSFET will turn on. The N-channel MOSFET device is
forced off when both the step-up converter and LDO are
in shutdown.
LDO REGULATOR OPERATION
⎛
⎝
⎞
⎟
⎠
R6
R5
VLBI = 0.58V 1+
⎜
TheLTC3537includesanindependent100mAlowdropout
linear regulator (LDO). The V pin can be connected to
INL
an independent source or connected to the output of the
boost regulator. An input capacitor on V is optional, but
BOOST POWER-GOOD INDICATOR
INL
it will help to improve transient responses. The LDO will
The LTC3537 includes a power-good comparator for the
step-upconverter.Thenon-invertinginputofthecompara-
tor is internally connected to a 1.08V reference and the
invertinginputisconnectedtotheFBBpin.Theopen-drain
MOSFET on PGDB will turn off when the output voltage
is typically within 6% of the programmed output voltage.
operate with a V down to 1.5V, but specifications are
INL
guaranteed with V from 1.8V to 5.5V.
INL
Shutdown
Shutdown of the LDO is accomplished by pulling ENLDO
below0.3VandenabledbypullingENLDOabove0.8V.Note
OutputsequencingcanbeachievedbyconnectingPGDBto
the LDO enable pin (ENLDO). This would allow the user to
keep the LDO off until the step-up converter is regulating.
The N-channel MOSFET is forced on in shutdown.
that ENLDO can be driven above V or V
, as long
INL
OLDO
as it is limited to less than the absolute maximum rating.
In the event that the LDO output voltage is held above the
inputvoltage,theLDOgoesintoshutdownuntiltheoutput
drops back below the input voltage. In shutdown the LDO
will block reverse current from V
to V
.
LDO POWER-GOOD INDICATOR
OLDO
INL
The LTC3537 includes a power-good comparator for the
LDO.Thenon-invertinginputofthecomparatorisinternally
connected to a 540mV reference and the inverting input is
connected to the FBL pin. The open-drain MOSFET on the
PGDL pin will turn off when the output voltage is typically
within 4% of the programmed output voltage.
LDO Error Amplifier
The non-inverting input of the transconductance error
amplifier is internally connected to a 0.6V reference and
the inverting input is connected to FBL. The control loop
compensation is provided internally. An external resistive
voltagedividerfromV
voltage via FBL from 0.6V to 5V.
togroundprogramstheoutput
OLDO
OutputsequencingcanbeachievedbyconnectingPGDLto
theboostenablepin(ENBST). Thiswouldallowtheuserto
keep the step-up converter off until the LDO is regulating.
The N-channel MOSFET is forced on in shutdown.
3537fd
⎛
⎞
⎟
⎠
R4
R3
VOLDO = 0.6V 1+
⎜
⎝
13
LTC3537
APPLICATIONS INFORMATION
V
> V
OPERATION
will help to lower the die temperature. A multilayer board
with a separate ground plane is ideal, but not absolutely
necessary.
INB
OUTB
TheLTC3537step-upconverterwillmaintainvoltageregu-
lation even when the input voltage is above the desired
outputvoltage.Notethattheefficiencyismuchlowerinthis
mode, and the maximum output current capability will be
less. Refer to the Typical Performance Characteristics.
COMPONENT SELECTION
Inductor Selection
The LTC3537 can utilize small surface mount chip induc-
tors due to its fast 2.2MHz switching frequency. Inductor
values between 1μH and 4.7μH are suitable for most ap-
plications. Larger values of inductance will allow slightly
greater output current capability (and lower the Burst
Mode threshold) by reducing the inductor ripple current.
Increasing the inductance above 10μH will increase size
while providing little improvement in output current capa-
bility. The minimum inductance value is given by:
STEP-UP SHORT-CIRCUIT PROTECTION
The LTC3537 output disconnect feature provides output
shortcircuitprotection.Toreducepowerdissipationunder
short-circuit conditions, the peak switch current limit is
reduced to 400mA (typical).
SCHOTTKY DIODE
Although it is not required, adding a Schottky diode from
SW to V
will improve efficiency by about 4%. Note
OUTB
V
• V
− V
INB(MIN)
OUTB(MAX)
(
)
INB(MIN)
that this defeats the output disconnect and short-circuit
L >
2.2 •Ripple•VOUTB(MAX)
protection features.
where:
PCB LAYOUT GUIDELINES
Ripple = Allowable inductor current ripple (amps
peak-peak)
ThehighspeedoperationoftheLTC3537demandscareful
attention to board layout. A careless layout will result in
reduced performance. Figure 1 shows the recommended
component placement. A large ground pin copper area
V
V
= Minimum converter input voltage
INB(MIN)
= Maximum output voltage
OUTB(MAX)
The inductor current ripple is typically set for 20% to
40% of the maximum inductor current. High frequency
ferritecoreinductormaterialsreducefrequencydependent
power losses compared to cheaper powdered iron types,
improving efficiency. The inductor should have low ESR
V
OUTB
LBO
SW
16 15 14 13
2
V
V
1
2
3
4
12
11
MODE
LBI
INL
(seriesresistanceofthewindings)toreducetheI Rpower
losses, and must be able to support the peak inductor
current without saturating. Molded chokes and some chip
inductorsusuallydonothaveenoughcoreareatosupport
thepeakinductorcurrentsof750mAseenontheLTC3537.
To minimize radiated noise, use a shielded inductor. See
Table 1 for suggested components and suppliers.
OLDO
SGND
10 FBL
+
9
FBB
V
INB
5
6
7
8
3537 F01
MULTIPLE VIAS
TO INNER GROUND LAYERS
PGDB ENBST PGDL ENLDO
Figure 1
3537fd
14
LTC3537
APPLICATIONS INFORMATION
Table 1: Recommended Inductors
wide voltage and temperature ranges. Y5V types should
not be used.
VENDOR
PART/STYLE
Coilcraft
LPO4815
TheinternalloopcompensationoftheLTC3537isdesigned
to be stable with a minimum output capacitor value of
4.7μF when in PWM mode on the boost regulator and
1μF or greater on the LDO regulator. Although ceramic
capacitors are recommended, low ESR tantalum capaci-
tors may be used as well. For the LDO, see Figures 2 and
3 for output capacitor value and ESR requirements. To
reduce Burst Mode boost output voltage ripple, 10μF is
recommended.
(847) 639-6400
www.coilcraft.com
LPS4012, LPS4018
MSS5131
MSS4020
MOS6020
ME3220
DS1605, DO1608
Coiltronics
www.cooperet.com
SD10, SD12, SD14, SD18,
SD20,
SD52, SD3114, SD3118
FDK
(408) 432-8331
www.fdk.com
MIP3226D4R7M,
MIP3226D3R3M
MIPF2520D4R7
MIPWT3226D3R0
1.6
1.4
1.2
1.0
0.8
Murata
(714) 852-2001
www.murata.com
LQH43C
LQH32C (-53 series)
301015
Sumida
(847) 956-0666
www.sumida.com
CDRH5D18
CDRH2D14
CDRH3D16
CDRH3D11
0.6
CR43
REGION OF
OPERATION
CMD4D06-4R7MC
CMD4D06-3R3MC
0.4
0.2
0.0
Taiyo-Yuden
www.t-yuden.com
NP03SB
NR3015T
NR3012T
1
10
100
CAPACITANCE (μF)
3537 F02
TDK
VLP
VLF, VLCF
Figure 2. LDO Regulator Output Capacitance vs ESR
(847) 803-6100
www.component.tdk.com
Toko
(408) 432-8282
www.tokoam.com
D412C
D518LC
D52LC
D62LCB
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Wurth
WE-TPC Type S, M
(201) 785-8800
www.we-online.com
Output and Input Capacitor Selection
Low ESR (equivalent series resistance) capacitors should
be used to minimize the output voltage ripple. Multilayer
ceramic capacitors are an excellent choice as they have
extremely low ESR and are available in small footprints.
A 4.7μF to 10μF output capacitor is sufficient for most
boost applications. Larger values up to 22μF may be used
to obtain extremely low output voltage ripple and improve
transient response. X5R and X7R dielectric materials are
preferred for their ability to maintain capacitance over
1
2
3
4
5
6
7
V
/V
INL OLDO
3537 F03
Figure 3. LDO Regulator Minimum Output Capacitance
vs VINL/VOLDO
3537fd
15
LTC3537
APPLICATIONS INFORMATION
Forthestep-upconverter,atantalumcapacitormaybeused
in demanding applications that have large load transients.
Another method of improving the transient response is to
add a small feedforward capacitor across the top resistor
it is not required. Table 2 shows a list of several ceramic
capacitor manufacturers. Consult the manufacturers di-
rectlyfordetailedinformationontheirselectionofceramic
capacitors.
ofthefeedbackdivider(fromV
of 22pF will generally suffice.
toFBB).Atypicalvalue
OUTB
Table 2. Capacitor Vendor Information
SUPPLIER
AVX
PHONE
WEBSITE
Ceramic capacitors are also a good choice for input de-
coupling of the step-up converter and should be located
as close as possible to the device. A 2.2μF input capacitor
is sufficient for most applications, although larger values
may be used without limitations. The LDO regulator will
have improved performance with an input capacitor, but
(803) 448-9411
(714) 852-2001
(408) 573-4150
(847) 803-6100
(408) 544-5200
www.avxcorp.com
www.murata.com
www.t-yuden.com
www.component.tdk.com
www.sem.samsung.com
Murata
Taiyo-Yuden
TDK
Samsung
3537fd
16
LTC3537
TYPICAL APPLICATIONS
1-Cell to 1.8V, 1.5V
2.2μH
SW
R6
V
OUTB
V
V
INB
OUTB
665k
1.8V
33pF
R2
499k
LTC3537
LBI
V
+
INL
10μF
LBO
ALKALINE
R5
1M
0.8V
TO
FBB
PGDB
PGDL
ENDLO
ENBST
MODE
V
OLDO
V
1.6V
OLDO
1μF
1.5V
R4
OFF ON
1.5M
1μF
PVM BURST
FBL
R1
1M
R3
1M
SGND PGND
3537 TA02
1-Cell to 3.3V, 2.8V
2.2μH
R6
V
SW
OUTB
V
V
OUTB
INB
665k
3.3V
33pF
R2
1.74M
LTC3537
LBI
LBO
V
+
INL
10μF
ALKALINE
R5
1M
0.8V
TO
PGDB
PGDL
ENDLO
ENBST
MODE
FBB
V
OLDO
V
1.6V
OLDO
1μF
2.8V
R4
OFF ON
1.1M
1μF
PVM BURST
FBL
R1
1M
R3
301k
SGND PGND
3537 TA03
3537fd
17
LTC3537
TYPICAL APPLICATIONS
2-Cell to Low Noise 3.3V
2.2μH
R6
2M
SW
V
V
OUTB
INB
+
2-CELL
ALKALINE
1.6V TO 3.2V
33pF
R2
2M
LTC3537
LBI
LBO
V
INL
10μF
R5
FBB
PGDB
PGDL
ENDLO
ENBST
MODE
1M
V
OLDO
V
OLDO
3.3V
1μF
R4
2.37M
OFF ON
1μF
PVM BURST
FBL
R1
1M
R3
523k
SGND PGND
3537 TA04
2-Cell to 5V, 1.8V
2.2μH
R6
V
SW
OUTB
V
V
OUTB
INB
2M
5V
+
2-CELL
ALKALINE
1.6V TO 3.2V
33pF
R2
1.91M
LTC3537
LBI
LBO
V
INL
10μF
R5
1M
FBB
PGDB
PGDL
ENDLO
ENBST
MODE
1μF
V
1.8V
OLDO
V
OLDO
R4
2M
OFF ON
1μF
PVM BURST
FBL
R1
604k
R3
1M
SGND PGND
3537 TA05
3537fd
18
LTC3537
TYPICAL APPLICATIONS
Li-Ion to 5V, 3.3V
2.2μH
SW
R6
V
OUTB
V
V
OUTB
INB
2M
5V
33pF
R2
1.91M
LTC3537
LBI
V
+
INL
10μF
LBO
Li-Ion
2.8V
TO
R5
499k
FBB
PGDB
PGDL
ENDLO
ENBST
MODE
V
3.3V
OLDO
V
OLDO
4.2V
1μF
R4
2.37M
OFF ON
PVM BURST
1μF
FBL
R1
604k
R3
523k
SGND PGND
3537 TA06
Single Cell or 5V Input to 3.3V
USB
OR
0.8V TO 1.6V
ALKALINE
2.2μH
5V ADAPTER
10ꢀF
+
R6
510k
SW
3.3V/100mA
V
V
OUTB
INB
+
R3
1.74M
33pF
1μF
LBI
V
INL
LBO
10μF
R5
1.02M
LTC3537
FBB
PGDB
PGDL
ENLDO
ENBST
MODE
R2
511k
V
OFF ON
OLDO
FBL
PWM BURST
R1
487k
SGND PGND
3537 TA07
3537fd
19
LTC3537
PACKAGE DESCRIPTION
UD Package
16-Lead Plastic QFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1691)
0.70 p 0.05
3.50 p 0.05
2.10 p 0.05
1.45 p 0.05
(4 SIDES)
PACKAGE OUTLINE
0.25 p 0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
BOTTOM VIEW—EXPOSED PAD
PIN 1 NOTCH R = 0.20 TYP
OR 0.25 s 45o CHAMFER
R = 0.115
TYP
0.75 p 0.05
3.00 p 0.10
(4 SIDES)
15 16
PIN 1
TOP MARK
(NOTE 6)
0.40 p 0.10
1
2
1.45 p 0.10
(4-SIDES)
(UD16) QFN 0904
0.200 REF
0.25 p 0.05
0.00 – 0.05
0.50 BSC
NOTE:
1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WEED-2)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
3537fd
20
LTC3537
REVISION HISTORY (Revision history begins at Rev D)
REV
DATE
12/12 Corrected from LBO to LBO
Corrected Burst Mode Quescent Current Graph
Corrected Typos
DESCRIPTION
PAGE NUMBER
D
Throughout
6
9
3537fd
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
21
LTC3537
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC3401
1A (I ), 3MHz, Synchronous Step-Up DC/DC Converter
97% Efficiency, V : 0.5V to 5V, V
= 6V, I = 38μA, I <1μA,
Q SD
SW
IN
OUT(MAX)
OUT(MAX)
10-Lead MS Package
LTC3402
LTC3421
LTC3422
2A (I ), 3MHz, Synchronous Step-Up DC/DC Converter
97% Efficiency, V : 0.5V to 5V, V
= 6V, I = 38μA, I <1μA,
Q SD
SW
IN
10-Lead MS Package
3A (I ), 3MHz, Synchronous Step-Up DC/DC Converter
95% Efficiency, V : 0.5V to 4.5V, V
= 5.25V, I = 12μA, I <1μA,
Q SD
SW
IN
OUT(MAX)
OUT(MAX)
OUT(MAX)
OUT(MAX)
with Output Disconnect
QFN24 Package
1.5A (I ), 3MHz Synchronous Step-Up DC/DC Converter 95% Efficiency, V : 0.5V to 4.5V, V
= 5.25V, I = 25μA, I <1μA,
Q SD
SW
IN
with Output Disconnect
3mm × 3mm DFN Package
LTC3423/LTC3424 1A/2A (I , 3MHz, Synchronous Step-Up DC/DC
95% Efficiency, V : 0.5V to 5.5V, V
= 5.5V, I = 38μA, I <1μA,
Q SD
SW)
Converters
IN
10-Lead MS Package
LTC3426
LTC3428
LTC3429
LTC3458
LTC3458L
2A (I ), 1.2MHz, Step-Up DC/DC Converter
92% Efficiency, V : 1.6V to 4.3V, V
= 5V, I <1μA,
SD
SW
IN
SOT-23 Package
500mA (I ), 1.25MHz/2.5MHz, Synchronous Step-Up
92% Efficiency, V : 1.8V to 5V, V
= 5.25V, I <1μA,
OUT(MAX) SD
SW
IN
DC/DC Converters with Output Disconnect
2mm × 2mm DFN Package
600mA (I ), 500kHz, Synchronous Step-Up DC/DC
96% Efficiency, V : 0.5V to 4.4V, V
= 5V, I = 20μA/300μA,
OUT(MAX) Q
SW
IN
Converter with Output Disconnect and Soft-Start
I
SD
<1μA, ThinSOT Package
1.4A (I ), 1.5MHz, Synchronous Step-Up DC/DC
93% Efficiency, V : 1.5V to 6V, V
= 7.5V, I = 15μA, I <1μA,
OUT(MAX) Q SD
SW
IN
Converter/Output Disconnect/Burst Mode Operation
DFN12 Package
1.7A (I ), 1.5MHz, Synchronous Step-Up DC/DC
94% Efficiency, V = 6V, I = 12μA, DFN12 Package
OUT(MAX) Q
SW
Converter with Output Disconnect, Automatic Burst Mode
Operation
LTC3459
LTC3522
70mA (I ), 10V Micropower Synchronous Boost
V : 1.5V to 5.5V, V
= 10V, I = 10μA, I <1μA,
SW
IN
OUT(MAX) Q SD
Converter/Output Disconnect/Burst Mode Operation
ThinSOT Package
400mA Synchronous Buck-Boost and 200mA
Synchronous Buck Converter
95% Efficiency, V : 2.4V to 5.5V, V : 5.25V to 0.6V, I = 25μA,
IN OUT Q
I
SD
< 1μA, 3mm × 3mm DFN Package
LTC3525-3/
LTC3525-3.3/
LTC3525-5
400mA Micropower Synchronous Step-Up DC/DC
Converter with Output Disconnect
95% Efficiency, V : 1V to 4.5V, V
SD
= 3.0V, 3.3V or 5V, I = 7μA,
OUT Q
IN
I
<1μA, SC-70 Package
LTC3525L-3
400mA Micropower Synchronous Step-Up DC/DC
Converter with Output Disconnect
90% Efficiency, V : 0.7V to 4.5V, V
= 3V, I = 7μA, I < 1μA,
OUT Q SD
IN
SC70 Package
LTC3526L/
LTC3526LB
550mA, 1MHz Synchronous Step-Up DC/DC Converter
95% Efficiency, V : 0.75V to 5V, V
SD
: 1.5V to 5.25V, I = 9μA,
OUT(MAX) Q
IN
I
<1μA, DFN6 Package
LTC3528/
LTC3528B
1A, 1MHz, Synchronous Step-Up DC/DC Converters
94% Efficiency, V : 0.7V to 5V, V : 1.6V to 5.25V, I = 12μA, I < 1μA,
IN OUT Q SD
2mm × 3mm DFN Package, LTC3528B (PWM Mode Only)
ThinSOT is a trademark of Linear Technology Corporation.
3537fd
LT 1212 REV D • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
22
●
●
© LINEAR TECHNOLOGY CORPORATION 2007
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
LTC3537EUD#PBF CAD模型
引脚图
封装焊盘图
LTC3537EUD#PBF 相关器件
| 型号 | 制造商 | 描述 | 价格 | 文档 |
| LTC3537EUD-PBF | Linear | 2.2 MHz, 600mA Synchronous Step-Up DC/DC Converter and 100mA LDO | 获取价格 |
|
| LTC3537EUD-TRPBF | Linear | 2.2 MHz, 600mA Synchronous Step-Up DC/DC Converter and 100mA LDO | 获取价格 |
|
| LTC3538 | Linear | 800mA Synchronous Buck-Boost DC/DC Converter | 获取价格 |
|
| LTC3538 | ADI | 800mA 同步降压-升压型 DC/DC 转换器 | 获取价格 |
|
| LTC3538EDCB | Linear | 800mA Synchronous Buck-Boost DC/DC Converter | 获取价格 |
|
| LTC3538EDCB#PBF | Linear | LTC3538 - 800mA Synchronous Buck-Boost DC/DC Converter; Package: DFN; Pins: 8; Temperature Range: -40&deg;C to 85&deg;C | 获取价格 |
|
| LTC3538EDCB#TR | Linear | 暂无描述 | 获取价格 |
|
| LTC3538EDCB#TRM | Linear | IC 0.8 A SWITCHING REGULATOR, 1200 kHz SWITCHING FREQ-MAX, PDSO8, 2 X 3 MM, PLASTIC, DFN-8, Switching Regulator or Controller | 获取价格 |
|
| LTC3538EDCB-PBF | Linear | 800mA Synchronous Buck-Boost DC/DC Converter | 获取价格 |
|
| LTC3538EDCB-TR | Linear | 800mA Synchronous Buck-Boost DC/DC Converter | 获取价格 |
|
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