ELM-TECH ELM9430B-S

ELM94xxB CMOS PFM step-up DC/DC converter
■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
High output voltage accuracy
Output current(e.g.)
Package
: 2.5V to 5.5V (by 0.1V)
: Vin≥0.98V (RL=30kΩ)
: 12μW (Typ. ELM9430B)
: Typ. 80%
: ±2.5%
: 20mA (When Vin=1.5V, Vout=3.0V)
: SOT-89
• Constant voltage source for batteryoperated devices
• Constant voltage source for cameras
• Portable communication equipments
• Local regulator
■Maximum absolute ratings
Parameter
Apply voltage to LX pin
Apply voltage to VOUT pin
Output current of LX pin
Power dissipation
Operating temperature
Storage temperature
Symbol
Vlx
Vout
Ilx
Pd
Top
Tstg
Limit
12
12
200
300
-40 to +85
-55 to +125
Unit
V
V
mA
mW
°C
°C
■Selection guide
ELM94xxB-x
Symbol
a, b
Output voltage
c
Product version
d
Taping direction
■Pin configuration
e.g. :
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 d
SOT-89 (TOP VIEW)
Pin No.
1
2
3
6-1
Pin name
VSS
VOUT
LX
ELM94xxB CMOS PFM step-up DC/DC converter
■Standard circuit
㪤㪘㪎㪉㪈
㪊㪊㪇㱘㪟
㪣㪯
㪭㫀㫅
㪜㪣㪤㪐㪋㫏㫏㪙
㪭㪦㪬㪫
㪭㫆㫌㫋
㪂
㪭㪪㪪
㪉㪉㱘㪝
■Block diagram
㪧㪅㪝㪅㪤㪅
㪣㪯
㪭㪦㪬㪫
㪂 㪄
㪭㫉㪼㪽
㪦㫊㪺㫀㫃㫃㪸㫋㫆㫉
㪪㫋㪸㫉㫋㪄㫌㫇
㪭㪪㪪
■Electrical characteristics
Vout=2.7V (ELM9427B)
Parameter
Input voltage
Starting voltage
Holding voltage
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
Symbol
Vin
Vst
Vhold
Iss
Vout
Ilx
Ilxl
Fosc
Duty
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition
Min. Typ. Max. Unit
10
V
RL=27kΩ
0.98
V
Iout=1mA
0.7
V
Iout=100μA, Vin=1.5V
3.5
7.0
μA
Iout=1mA, Vin=1.5V
2.63 2.70
2.77
V
Vout=2.6V, Vlx=0.4V
80
mA
Vout=Vlx=10V
1.0
μA
Vout=2.6V
22
35
55
kHz
Vout=2.6V, Switch"ON"
45
55
65
%
Symbol
Vin
Vst
Vhold
Iss
Vout
Ilx
Ilxl
Fosc
Duty
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition
Min. Typ. Max. Unit
10
V
RL=30kΩ
0.98
V
Iout=1mA
0.7
V
Iout=100μA, Vin=1.5V
4.0
8.0
μA
Iout=1mA, Vin=1.5V
2.92 3.00
3.08
V
Vout=2.9V, Vlx=0.4V
90
mA
Vout=Vlx=10V
1.0
μA
Vout=2.9V
22
35
55
kHz
Vout=2.9V, Switch"ON"
45
55
65
%
Vout=3.0V (ELM9430B)
Parameter
Input voltage
Starting voltage
Holding voltage
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
6-2
ELM94xxB CMOS PFM step-up DC/DC converter
Symbol
Vin
Vst
Vhold
Iss
Vout
Ilx
Ilxl
Fosc
Duty
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition
Min. Typ. Max. Unit
10
V
RL=33kΩ
0.98
V
Iout=1mA
0.7
V
Iout=100μA, Vin=1.5V
4.5
9.0
μA
Iout=1mA, Vin=1.5V
3.21 3.30
3.39
V
Vout=3.2V, Vlx=0.4V
100
mA
Vout=Vlx=10V
1.0
μA
Vout=3.2V
22
35
55
kHz
Vout=3.2V, Switch"ON"
45
55
65
%
Symbol
Vin
Vst
Vhold
Iss
Vout
Ilx
Ilxl
Fosc
Duty
L=330μH, D=MA721, C=22μF, Vss=0V, Top=25°C
Condition
Min. Typ. Max. Unit
10
V
RL=50kΩ
0.98
V
Iout=1mA
0.9
V
Iout=100μA, Vin=3V
7.0
14.0
μA
Iout=1mA, Vin=3V
4.87 5.00
5.13
V
Vout=4.8V, Vlx=0.4V
130
mA
Vout=Vlx=10V
1.0
μA
Vout=4.8V
22
35
58
kHz
Vout=4.8V, Switch"ON"
50
60
70
%
Vout=3.3V (ELM9433B)
Parameter
Input voltage
Starting voltage
Holding voltage
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
Vout=5.0V (ELM9450B)
Parameter
Input voltage
Starting voltage
Holding voltage
Current consumption
Output voltage
Output current of LX pin
Leakage current of LX pin
Oscillating frequency
Maximum duty ratio
■Marking
SOT-89
㪸
㪹
a : the integer digit of the output voltage
Mark
2
3
Vout
2.*V
3.*V
Mark
4
5
Vout
4.*V
5.*V
b : the decimal digit of the output voltage
㪺
㪻
Mark
0
1
2
3
4
Vout
*.0V
*.1V
*.2V
*.3V
*.4V
c : Assembly lot No.
0 to 9
d : Assembly lot No.
A to Z (excepted I, O, X)
6-3
Mark
5
6
7
8
9
Vout
*.5V
*.6V
*.7V
*.8V
*.9V
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
8 • L • Fosc • (Vout-Vin) * Duty=50%
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. Solution 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 methods 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 (%)
(%)
EFFICIENCY
100
Vout (V)
3
Iout =1mA
2
3mA
10mA
1
0
1
Efficiency
EFFICIENCY
90
200
150
80
RIPPLE
VOLTAGE
VRp-p
70
100
50
60
50
2
Vin (V)
(Iout =1mA)
250
0
1
0
2
Vin (V)
VRp-p (mV)(mV)
RIPPLE VOLTAGE
EFFICIENCY-Vin
ǯ,VRp-p - Vin
RIPPLE VOLTAGE-Vin
Vout - Vin
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(%)
(%)
EFFICIENCY
100
Vout (V)
3
Iout =1mA
2
3mA
10mA
1
0
1
Vin (V)
2
EFFICIENCY
Efficiency
90
200
80
150
RIPPLE
VOLTAGE
VRp-p
70
100
60
50
3
6-5
250
50
0
1
Vin (V)
2
3
0
(mV)(mV)
RIPPLE VRp-p
VOLTAGE
EFFICIENCY-Vin
ǯ,VRp-p - Vin (Iout =1mA)
RIPPLE VOLTAGE-Vin
Vout - Vin
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
Efficiency (%)
(%)
100
3
Vout (V)
Iout =1mA
3mA
2
10mA
EFFICIENCY
Efficiency
90
200
80
150
VRp-p
RIPPLE
VOLTAGE
70
100
60
1
0
1
Vin (V)
2
50
3
250
50
0
1
Vin (V)
2
3
RIPPLE VOLTAGE
VRp-p (mV)(mV)
EFFICIENCY-Vin
ǯ,VRp-p - Vin
RIPPLE VOLTAGE-Vin (Iout =1mA)
Vout - Vin
0
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
ǯ,VRp-p - Vin (Iout =1mA)
RIPPLE VOLTAGE-Vin
Vout - Vin
Vout (V)
5
Iout =1mA
3mA
4
3
10mA
0
1
Vin (V)
2
6-6
EFFICIENCY
Efficiency
90
400
80
300
VRp-p
RIPPLE
VOLTAGE
70
200
60
50
3
500
100
0
1
2
3
Vin (V)
4
5
0
VRp-p (mV)(mV)
RIPPLE VOLTAGE
Efficiency
(%)
EFFICIENCY
(%)
100