SE3507-LF [SEAWARD]
1MHz, 2.5A Step-up Current Mode PWM Converter;
| 型号： | SE3507-LF |
| 厂家： | 
Seaward Electronics Inc. |
| 描述： | 1MHz, 2.5A Step-up Current Mode PWM Converter |
| 文件： | 总7页 (文件大小：441K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
General Description
Features
The SE3507 is a current mode boost DC-DC
converter. Its PWM circuitry with built-in 0.16Ω power
MOSFET make this regulator highly power efficient.
The internal compensation network also minimizes as
Adjustable Output up to 6V
Internal Fixed PWM frequency: 1.0MHz
Precision Feedback Reference Voltage: 1.275V
(±2%)
much as
6
external component counts. The
Internal 0.16Ω, 2A, 6V Power MOSFET
Shutdown Current: 0.1μA
non-inverting input of error amplifier connects to a
1.275V precision reference voltage and internal
soft-start function can reduce the inrush current.
The SE3507 is available in the SOT23-6 package and
provides space-saving PCB for the application fields.
Over Temperature Protection
Adjustable Over Current Protection: 0.5A ~ 2.5A
Package: SOT23-6
Application
Chargers
LCD Displays
Digital Cameras
Handheld Devices
Portable Products
Typical Application
R1
R2
Vout 1.275V 1
Rev1.0
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc. • www.seawardinc.com.cn • Page 1
1/7/2013
Pin Configuration
Pin Description
Number
Pin
SW
GND
FB
Pin Function Description
1
2
3
4
5
6
Switch pin
Power ground
Feedback pin
EN
Shutdown control input, Connect this pin to logic high level to enable the device
Input power supply pin
IN
OC
Adjustable Current Limit
Ordering Information
Marking Information
Package
Part Number
Remarks
Starting with 5, a bar on top of 5 is for
production year 2011, and underlined 5
is for year 2012. The next character is
marked on top for 2013, and underlined
for 2014. The naming pattern continues
with consecutive characters for later
years.
SE3507-LF
SOT23-6
The character “x” is the week code.
(A-Z: 1-26, a-z: 27-52)
The last character “L” is for lead-free
process.
A dot on bottom left corner is Pin 1.
Rev1.0
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc. • www.seawardinc.com.cn • Page 2
1/7/2013
Functional Block Diagram
Absolute Maximum Ratings
Parameter
Supply Voltage VIN
Symbol
VCC
Maximum
Units
V
6
6
SW Voltage
VSW
V
FB, EN Voltage
6
V
Power Dissipation
PD
θJA
TJ
455
mW
°C /W
°C
Thermal Resistance
Junction Temperature
Operating Temperature
Storage Temperature
Lead Temperature (Soldering, 10 sec)
+220
+150
-40 to +85
-65 to 150
+260
TOP
TST
°C
°C
°C
Recommended Operating Conditions
Parameter
Supply Voltage
Symbol
Min
2.6
Typ
Max
Unit
V
VIN
TA
5.5
Operating Temperature Range
-40
+85
℃
Rev1.0
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc. • www.seawardinc.com.cn • Page 3
1/7/2013
Electrical Characteristics
VIN = 3.3V, TA= 25℃; unless otherwise specified
Symbol
Parameter
Test Conditions
Min
Typ
Max
Unit
System Supply Input
VCC
Input Supply Range
Under Voltage Lockout
UVLO Hysteresis
2.6
5.5
V
V
VUVLO
2.6
0.1
0.3
2
V
ICC
ICC
Quiescent Current
VFB=1.3V, No switching
VFB=1.2V, Switching
VEN=GND
mA
mA
μA
Average Supply Current
Shutdown Supply Current
ICC
0.1
Oscillator
FOSC
Operation Frequency
Frequency Change with Voltage
Maximum Duty Cycle
VFB=1.0V
MHZ
%
0.8
1.0
5
1.2
1.3
0.7
VCC=2.6V to 5.5V
△f / △V
TDUTY
90
%
Reference Voltage
VREF
Reference Voltage
Line Regulation
1.25 1.275
0.05
V
VCC=2.6V_5.5V
%/V
Enable Control
VEN
Enable Voltage
0.9
V
V
VEN
Shutdown Voltage
MOSFET
RDS (ON)
Protection
IOCP
On Resistance of Driver
Isw=2A
0.16
Ω
OCP Current
Adjustable OCP Current
OTP Temperature
With External Resistor：20k
2
A
A
IOCP
With External Resistor：16k~80k
0.5
2.5
TOTP
+150
℃
Rev1.0
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc. • www.seawardinc.com.cn • Page 4
1/7/2013
Functional Description
Operation
Current Limit Program
The SE3507 is a current mode boost converter.
A resistor between OC and GND pin programs
The constant switching frequency is 1MHz and peak switch current. The resistor value should be
operates with pulse width modulation (PWM). Build-in between 16k and 80k. The current limit will be set
6V / 2A MOSFET provides a high output voltage. The from 2.5A to 0.5A. Keep traces at this pin as short as
control loop architecture is peak current mode control; possible.
therefore slope compensation circuit is added to the Do not put capacitance at this pin. To set the over
current signal to allow stable operation for duty cycles current trip point according to the following equation:
larger than 50%.
40000
IOCP
R3
Soft Start Function
Soft start circuitry is integrated into SE3507 to
avoid inrush current during power on. After the IC is
Over Temperature Protection (OTP)
SE3507 will turn off the power MOSFET
enabled, the output of error amplifier is clamped by automatically when the internal junction temperature
the internal soft-start function, which causes PWM is over 150°C. The power MOSFET wake up when the
pulse width increasing slowly and thus reducing input junction temperature drops 30°C under the OTP
surge current.
threshold temperature.
Application Information
Inductor Selection
Inductance value is decided based on different condition. 3.3uH to 4.7μH inductor value is recommended
for general application circuit. There are three important inductor specifications, DC resistance, saturation
current and core loss. Low DC resistance has better power efficiency. Also, it avoids inductor saturation which
will cause circuit system unstable and lower core loss at 1 MHZ.
Capacitor Selection
The output capacitor is required to maintain the DC voltage. Low ESR capacitors are preferred to reduce
the output voltage ripple. Ceramic capacitor of X5R and X7R are recommended, which have low equivalent
series resistance (ESR) and wider operation temperature range.
Diode Selection
Schottky diodes with fast recovery times and low forward voltages are recommended. Ensure the diode
average and peak current ratings exceed the average output current and peak inductor current. In addition, the
diode’s reverse breakdown voltage must exceed the output voltage.
Rev1.0
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc. • www.seawardinc.com.cn • Page 5
1/7/2013
Output Voltage Programming
The output voltage is set by a resistive voltage divider from the output voltage to FB. The output voltage
is:
R1
R2
VOUT 1.275V 1
Layout Considerations
1. The power traces, consisting of the GND trace, the SW trace and the VIN trace should be kept short, direct
and wide.
2.SW、L and D switching node, wide and short trace to reduce EMI.
3. Place CIN near VIN pin as closely as possible to maintain input voltage steady and filter out the pulsing input
current.
4. The resistive divider R1and R2 must be connected to FB pin directly as closely as possible.
5. FB is a sensitive node. Please keep it away from switching node, SW.
6. The GND of the IC, CIN and COUT should be connected close together directly to a ground plane.
Rev1.0
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc. • www.seawardinc.com.cn • Page 6
1/7/2013
Outline Drawing For SOT23-6
联系方式：
北京思旺电子技术有限公司–中国总部
地址：中国北京市海淀区信息路 22 号上地科技综合楼 B 座二层
邮编：100085
电话:010-82895700/1/5
传真:010-82895706
Seaward Electronics Corporation – 台湾办事处
2F, #181, Sec. 3, Minquan East Rd,
Taipei, Taiwan R.O.C
电话: 886-2-2712-0307
传真: 886-2-2712-0191
Seaward Electronics Incorporated – 北美办事处
1512 Centre Pointe Dr.
Milpitas, CA95035, USA
电话: 1-408-821-6600
Rev1.0
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc. • www.seawardinc.com.cn • Page 7
1/7/2013
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