概述
数据手册ELM9427B-S 概述
CMOS PFM step-up DC/DC converter CMOS PFM升压DC / DC转换器
ELM9427B-S 数据手册
通过下载ELM9427B-S数据手册来全面了解它。这个PDF文档包含了所有必要的细节，如产品概述、功能特性、引脚定义、引脚排列图等信息。
PDF下载CMOS PFM step-up DC/DC converter
ELM94xxB
■General description
ELM94xxB is CMOS step-up DC/DC converter which consists of reference voltage source, error amplifier,
oscillation circuit, start-up circuit, PFM control circuit, switching transistor and output voltage setting resistor.
For external parts, coil, diode and capacitor are possible choices; with external parts, ELM94 series is able to
acquire constant output voltage higher than input voltage. The standard output voltages are 2.7V, 3.0V, 3.3V, and
5.0V; ELM94 series can also be designed as semi-custom IC within the range of 2.5V to 5.5V by 0.1V step.
■Features
■Application
• Output voltage range
• Low voltage operation
• Low power operation
• High efficiency
: 2.5V to 5.5V (by 0.1V)
: Vin≥0.98V (RL=30kΩ)
: 12μW (Typ. ELM9430B)
: Typ. 80%
• Constant voltage source for battery-
operated devices
• Constant voltage source for cameras
• Portable communication equipments
• Local regulator
• High output voltage accuracy : 2.5%
• Output current(e.g.)
• Package
: 20mA (When Vin=1.5V, Vout=3.0V)
: SOT-89
■Maximum absolute ratings
Parameter
Apply voltage to LX pin
Apply voltage to VOUT pin
Output current of LX pin
Power dissipation
Symbol
Vlx
Vout
Ilx
Pd
Top
Limit
12
12
200
300
-40 to +85
-55 to +125
Unit
V
V
mA
mW
°C
Operating temperature
Storage temperature
Tstg
°C
■Selection guide
ELM94xxB-x
Symbol
e.g. :
a, b
Output voltage
27: Vout=2.7V 30: Vout=3.0V
33: Vout=3.3V 50: Vout=5.0V
B
S : Refer to PKG file
N: Refer to PKG file
ELM94 x x B - x
↑ ↑ ↑ ↑
a b c
c
Product version
Taping direction
d
d
■Pin configuration
SOT-89 (TOP VIEW)
Pin No.
Pin name
VSS
VOUT
LX
1
2
3
6 - 1
ELM94xxB CMOS PFM step-up DC/DC converter
■Standard circuit
᎔ᎈ፹፸
፺፺፷ᕈᎏ
᎓
᎖
ᎰᎵ
ᎶᎼᎻ
፹፹ᕈᎍ
ᎌ᎓᎔ᎀ፻ᎿᎿᎉ
፲
■Block diagram
᎗፵ᎍ፵᎔፵
᎓
᎖
፲
፴
ᎹᎬᎭ
᎖ᎺᎪᎰᎳᎳᎨᎻᎶᎹ
ᎻᎨᎹᎻ፴ᎼᎷ
■Electrical characteristics
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition Min. Typ. Max. Unit
Vout=2.7V (ELM9427B)
Parameter
Symbol
Vin
Vst RL=27kΩ
Vhold Iout=1mA
Input voltage
Starting voltage
Holding voltage
10
0.98
0.7
V
V
V
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
Iss Iout=100μA, Vin=1.5V
Vout Iout=1mA, Vin=1.5V
Ilx Vout=2.6V, Vlx=0.4V
Ilxl Vout=Vlx=10V
Fosc Vout=2.6V
Duty Vout=2.6V, Switch"ON"
3.5
7.0
μA
V
mA
μA
kHz
%
2.63 2.70 2.77
80
1.0
55
65
22
45
35
55
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition Min. Typ. Max. Unit
Vout=3.0V (ELM9430B)
Parameter
Input voltage
Starting voltage
Holding voltage
Symbol
Vin
Vst RL=30kΩ
10
0.98
0.7
V
V
V
Vhold Iout=1mA
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
Iss Iout=100μA, Vin=1.5V
Vout Iout=1mA, Vin=1.5V
Ilx Vout=2.9V, Vlx=0.4V
Ilxl Vout=Vlx=10V
Fosc Vout=2.9V
Duty Vout=2.9V, Switch"ON"
4.0
8.0
μA
V
mA
μA
kHz
%
2.92 3.00 3.08
90
1.0
55
65
22
45
35
55
6 - 2
ELM94xxB CMOS PFM step-up DC/DC converter
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition Min. Typ. Max. Unit
Vout=3.3V (ELM9433B)
Parameter
Input voltage
Symbol
Vin
Vst RL=33kΩ
Vhold Iout=1mA
10
0.98
0.7
V
V
V
Starting voltage
Holding voltage
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
Iss Iout=100μA, Vin=1.5V
Vout Iout=1mA, Vin=1.5V
Ilx Vout=3.2V, Vlx=0.4V
Ilxl Vout=Vlx=10V
Fosc Vout=3.2V
Duty Vout=3.2V, Switch"ON"
4.5
9.0
μA
V
mA
μA
kHz
%
3.21 3.30 3.39
100
1.0
55
65
22
45
35
55
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition Min. Typ. Max. Unit
Vout=5.0V (ELM9450B)
Parameter
Input voltage
Starting voltage
Holding voltage
Symbol
Vin
Vst RL=50kΩ
10
0.98
0.9
V
V
Vhold Iout=1mA
V
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
Iss Iout=100μA, Vin=3V
Vout Iout=1mA, Vin=3V
Ilx Vout=4.8V, Vlx=0.4V
Ilxl Vout=Vlx=10V
Fosc Vout=4.8V
Duty Vout=4.8V, Switch"ON"
7.0
14.0
μA
V
mA
μA
kHz
%
4.87 5.00 5.13
130
1.0
58
70
22
50
35
60
■Marking
a : the integer digit of the output voltage
SOT-89
Mark
2
3
Vout
2. V
3. V
*
Mark
4
5
Vout
4. V
*
*
Ꭸ
Ꭺ
Ꭹ
Ꭻ
5. V
*
b : the decimal digit of the output voltage
Mark
Vout
Mark
Vout
0
1
2
3
4
.0V
.1V
.2V
.3V
.4V
5
6
7
8
9
.5V
.6V
.7V
.8V
.9V
*
*
*
*
*
*
*
*
*
*
c : Assembly lot No.
0 to 9
d : Assembly lot No.
A to Z (excepted I, O, X)
6 - 3
ELM94xxB CMOS PFM step-up DC/DC converter
■External parts
To design DC/DC converter with ELM94 series, coil, diode, and capacitor are necessary.
(Refer to standard circuit configuration.)
1) Coil
When choosing choke coil, please select that whose core is not magnetically saturated, DC resistance is
low, and which has sufficient margin for rated current.
For ELM94 series, ELM recommends following coil.
• CM-5/CM-5N (Sumida Electric Co., Ltd.)
2) Diode
When choosing diode, please select that whose forward voltage is small, switching speed is high and which
has sufficient margin for rated current.
For ELM94 series, ELM recommends schottoky diodes.
3) Capacitor
When choosing capacitor, please select that which is generally used for smoothing power supply circuit,
with comparatively large capacity and whose rated voltage is at least three times larger than rated output
voltage of used ELM94 series.
For ELM94 series, ELM recommends Aluminum electrolytic or Tantalum capacitor.
■Design of DC/DC converter
In DC/DC converter which consists of ELM94 series and above-mentioned external parts, the output is
acquired as follows:
1) Output current of DC/DC converter
The current from output terminal (Vout) of the circuit is:
Vin 2
Iout = K
Duty=50%
*
8 • L • Fosc • (Vout-Vin)
K: the efficiency of whole circuit (≈75% to ≈85%)
2) Remedies for noise
This DC/DC converter may cause electromagnetic noise due to switching of coil under large current. Solu-
tion is necessary especially when the IC is used in wireless devices.
To reduce noise, this IC is designed in consideration of coil switching characteristics. The following meth-
ods are also effective to reduce noise.
• Use shield-type, or magnetic shield coil.
• Locate coil and diode to the LX terminal of IC as close as possible.
• Select ground wire as thick and short as possible.
• Connect ground wire of circuit to one point.
6 - 4
ELM94xxB CMOS PFM step-up DC/DC converter
■Typical characteristics
䊶 㪭㫆㫌㫋㪔㪉㪅㪎㪭㩷㩿㪜㪣㪤㪐㪋㪉㪎㪙㪀㩷㩷㩷㩷㩷㩿㪫㫆㫇㪔㪉㪌㷄㪃㩷㪣㪔㪊㪊㪇㱘㪟㪃㩷㪛㪔㪤㪘㪎㪉㪈㪃㩷㪚㪔㪉㪉㱘㪝㪀㩷
EFFICIENCY-Vin
Vout - Vin
(Iout =1mA)
250
RIPPLE VOLTAGE-Vin
100
90
80
70
60
50
EFEFfIfCicIEieNnCcyY
200
150
100
50
3
2
1
Iout =1mA
3mA
RIPPLVERVpO-pLTAGE
10mA
0
0
1
2
0
1
2
Vin (V)
Vin (V)
䊶 㪭㫆㫌㫋㪔㪊㪅㪇㪭㩷㩿㪜㪣㪤㪐㪋㪊㪇㪙㪀㩷㩷㩷㩷㩷㩿㪫㫆㫇㪔㪉㪌㷄㪃㩷㪣㪔㪊㪊㪇㱘㪟㪃㩷㪛㪔㪤㪘㪎㪉㪈㪃㩷㪚㪔㪉㪉㱘㪝㪀㩷
EFFICIENCY-Vin
Vout - Vin
(Iout =1mA)
RIPPLE VOLTAGE-Vin
100
90
80
70
60
50
250
200
150
100
50
EFFICIENCY
Efficiency
3
2
1
Iout =1mA
3mA
RIPPLVERVpO-pLTAGE
10mA
0
0
1
2
3
0
1
2
3
Vin (V)
Vin (V)
6 - 5
ELM94xxB CMOS PFM step-up DC/DC converter
䊶 㪭㫆㫌㫋㪔㪊㪅㪊㪭㩷㩿㪜㪣㪤㪐㪋㪊㪊㪙㪀㩷㩷㩷㩷㩷㩿㪫㫆㫇㪔㪉㪌㷄㪃㩷㪣㪔㪊㪊㪇㱘㪟㪃㩷㪛㪔㪤㪘㪎㪉㪈㪃㩷㪚㪔㪉㪉㱘㪝㪀㩷
EFFICIENCY-Vin
Vout - Vin
(Iout =1mA)
RIPPLE VOLTAGE-Vin
100
90
80
70
60
50
250
200
150
100
50
EFFICIENCY
Effciency
3
2
1
Iout =1mA
3mA
RIPPLVERVpO-LpTAGE
10mA
0
0
1
2
3
0
1
2
3
Vin (V)
Vin (V)
䊶 㪭㫆㫌㫋㪔㪌㪅㪇㪭㩷㩿㪜㪣㪤㪐㪋㪌㪇㪙㪀㩷㩷㩷㩷㩷㩿㪫㫆㫇㪔㪉㪌㷄㪃㩷㪣㪔㪊㪊㪇㱘㪟㪃㩷㪛㪔㪤㪘㪎㪉㪈㪃㩷㪚㪔㪉㪉㱘㪝㪀㩷
EFFICIENCY-Vin
Vout - Vin
(Iout =1mA)
RIPPLE VOLTAGE-Vin
100
90
80
70
60
50
500
400
300
200
100
0
EFFICIENCY
Efciency
5
4
3
Iout =1mA
3mA
RIPPLVERVpOpLTAGE
10mA
0
1
2
3
4
5
0
1
2
3
Vin (V)
Vin (V)
6 - 6
ELM9427B-S 相关器件
| 型号 | 制造商 | 描述 | 价格 | 文档 |
| ELM9430B-N | ELM-TECH | CMOS PFM step-up DC/DC converter | 获取价格 |
|
| ELM9430B-S | ELM-TECH | CMOS PFM step-up DC/DC converter | 获取价格 |
|
| ELM9433B-N | ELM-TECH | CMOS PFM step-up DC/DC converter | 获取价格 |
|
| ELM9433B-S | ELM-TECH | CMOS PFM step-up DC/DC converter | 获取价格 |
|
| ELM9450B-N | ELM-TECH | CMOS PFM step-up DC/DC converter | 获取价格 |
|
| ELM9450B-S | ELM-TECH | CMOS PFM step-up DC/DC converter | 获取价格 |
|
| ELM95 | ELM-TECH | CMOS PWM step-up DC/DC converter | 获取价格 |
|
| ELM95-SERIES | ELM-TECH | CMOS PWM step-up DC/DC converter | 获取价格 |
|
| ELM9527D-N | ELM-TECH | CMOS PWM step-up DC/DC converter | 获取价格 |
|
| ELM9527D-S | ELM-TECH | CMOS PWM step-up DC/DC converter | 获取价格 |
|
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