ELM95xxD
CMOS PWM step-up DC/DC converter
■General description
ELM95xxD series is CMOS PWM step-up DC/DC converter which consists of reference voltage source, error
amplifier, oscillation circuit, start-up circuit, PWM control circuit, switch transistor and output voltage setting
resistor. For external parts, coil, diode and capacitor are possible choices; with external parts, ELM95 series
can acquire constant output voltage higher than input voltage. The standard output voltages are 2.7V,3.0V,3.3V
and 5.0V; ELM95 series can also be designed as semi-custom IC within the range of 2.5V to 5.5V by 0.1V step.
With newly-developed PWM control circuit, ELM95 series is able to modulate switching time smoothly with
constant frequency and consequently generates stable output with small ripples.
■Features
•
•
•
•
•
•
•
•
•
Output voltage range
: 2.5V to 5.5V (by 0.1V)
Low voltage operation
: Vin≥0.98V (RL=30kΩ)
Low power operation
: 35μW (Typ. ELM9530D)
High efficiency
: Typ. 85%
High output voltage accuracy : ±2.5%
Output current (e.g.)
: 10mA (When Vin=1.5V, Vout=3.0V)
Constant output frequency : Typ. 55kHz
Small ripples
Package
: SOT-89
■Application
• Constant voltage source for battery-
operated 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
ELM95xxD-x
Symbol
e.g.:
27: Vout=2.7V
30: Vout=3.0V
33: Vout=3.3V
50: Vout=5.0V
D
S : Refer to PKG file
N : Refer to PKG file
a, b
Output voltage
ELM95 x x D - x
↑ ↑ ↑ ↑
a b c d
c
d
Product version
Taping direction
5- 1
ELM95xxD
CMOS PWM step-up DC/DC converter
■Pin configuration
SOT-89 (TOP VIEW)
Pin No.
1
2
3
Pin name
VSS
VOUT
LX
■Standard circuit
■Block diagram
■Electrical characteristics
Vout=2.7V (ELM9527D)
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
L=220μH, D=MA721, C=47μF, Vss=0V, Top=25°C
Symbol
Condition
Min. Typ. Max. Unit
Vin
10
V
Vst RL=27kΩ
0.98
V
Vhold Iout=1mA
0.7
V
Iss Vin=1.5V
9.0
18.0
μA
Vout Iout=1mA, Vin=1.5V
2.63 2.70
2.77
V
Ilx Vout=2.6V, Vlx=0.4V
70
mA
Ilxl Vout=Vlx=10V
1.0
μA
Fosc Vout=2.6V
35
55
75
kHz
Duty Vout=2.6V
45
60
75
%
L=220μH, D=MA721, C=47μF, Vss=0V, Top=25°C
Condition
Min. Typ. Max. Unit
10
V
RL=30kΩ
0.98
V
Iout=1mA
0.7
V
Vin=1.5V
12.0 20.0
μA
Iout=1mA, Vin=1.5V
2.92
3.00 3.08
V
Vout=2.9V, Vlx=0.4V
80
mA
Vout=Vlx=10V
1.0
μA
Vout=2.9V
35
55
75
kHz
Vout=2.9V
45
60
75
%
Vout=3.0V (ELM9530D)
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
5- 2
ELM95xxD
CMOS PWM step-up DC/DC converter
Vout=3.3V (ELM9533D)
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
L=220μH, D=MA721, C=47μF, Vss=0V, Top=25°C
Symbol
Condition
Min. Typ. Max. Unit
Vin
10
V
Vst RL=33kΩ
0.98
V
Vhold Iout=1mA
0.7
V
Iss Vin=1.5V
14.0
23.0
μA
Vout Iout=1mA, Vin=1.5V
3.21 3.30
3.39
V
Ilx Vout=3.2V, Vlx=0.4V
80
mA
Ilxl Vout=Vlx=10V
1.0
μA
Fosc Vout=3.2V
35
55
75
kHz
Duty Vout=3.2V
45
60
75
%
Vout=5.0V (ELM9550D)
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
L=220μH, D=MA721, C=47μF, Vss=0V, Top=25°C
Symbol
Condition
Min. Typ. Max. Unit
Vin
10
V
Vst RL=50kΩ
0.98
V
Vhold Iout=1mA
0.9
V
Iss Vin=3V
30.0
45.0
μA
Vout Iout=1mA, Vin=3V
4.87 5.00
5.13
V
Ilx Vout=4.8V, Vlx=0.4V
110
mA
Ilxl Vout=Vlx=10V
1.0
μA
Fosc Vout=4.8V
35
55
75
kHz
Duty Vout=4.8V
45
60
75
%
■Marking
SOT-89
a : the integer digit of the output voltage
Mark
Vout
Mark
2
2.*V
4
3
3.*V
5
b : the decimal digit of the output voltage
Mark
Vout
Mark
0
5
*.0V
1
6
*.1V
2
7
*.2V
3
8
*.3V
4
9
*.4V
c : Assembly lot No.
A to Z (excepted I, O, X)
d : Assembly lot No.
0 to 9
Vout
4.*V
5.*V
Vout
*.5V
*.6V
*.7V
*.8V
*.9V
5- 3
ELM95xxD
CMOS PWM step-up DC/DC converter
■External parts
To design DC/DC converter with ELM95 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 ELM95 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 ELM95 series, ELM recommends schottoky diodes.
3) Capacitor
When choosing capacitor, please select that whose capacity is comparatively large and voltage limit is at
least three times larger than rated output voltage of used ELM95 series. For ELM95 series, ELM recom-
mends to use “Aluminum electrolytic capacitor”. When using capacitors such as “Tantalum capacitor” or
“Laminated ceramic capacitor”, there may be cases that few hundred hertz wave motion will happen in out-
put voltage wave form. Under such circumstances, ELM recommends connecting resistance (1.0Ω approx.)
to capacitor serially as following.
■Typical characteristics
• Vout=2.7V (ELM9527D)
Vout - Vin
100
(Top=25°C, L=220μH, D=MA721, C=47μF)
EFFICIENCY-Vin
- Vin
Efficiency,VRp-p
(Iout =1mA)
RIPPLE VOLTAGE-Vin
EFFICIENCY
EFFICIENCY
50
40
30
VRp-p
RIPPLE VOLTAGE
20
10
0
3
90
80
70
60
50
2
Iout =1mA
3mA
10mA
1
0
1
Vin (V)
2
0
1
Vin (V)
2
5- 4
RIPPLE VOLTAGE (mA)
VRp-p (mV)
EFFICIENCY (%)
Efficiency (%)
Vout (V)
ELM95xxD
CMOS PWM step-up DC/DC converter
• Vout=3.0V (ELM9530D)
Vout - Vin
100
(Top=25°C, L=220μH, D=MA721, C=47μF)
EFFICIENCY-Vin
- Vin
Efficiency,VRp-p
(Iout=1mA)
RIPPLE VOLTAGE-Vin
Efficiency
EFFICIENCY
50
40
30
VRp-p
RIPPLE VOLTAGE
20
10
0
3
90
80
70
60
50
2
Iout =1mA
3mA
10mA
1
0
1
Vin (V)
2
3
0
1
Vin (V)
2
3
• Vout=3.3V (ELM9533D)
Vout - Vin
(Top=25°C, L=220μH, D=MA721, C=47μF)
100
EFFICIENCY-Vin
- Vin
Efficiency,VRp-p
(Iout =1mA)
RIPPLE VOLTAGE-Vin
EFFICIENCY
Efficiency
50
40
30
3
90
80
70
60
50
VRp-p
RIPPLE VOLTAGE
2
Iout =1mA
3mA
10mA
20
10
0
1
0
1
Vin (V)
2
3
0
1
Vin (V)
2
3
• Vout=5.0V (ELM9550D)
Vout - Vin
(Top=25°C, L=220μH, D=MA721, C=47μF)
100
EFFICIENCY-Vin
- Vin
Efficiency,VRp-p
(Iout =1mA)
RIPPLE VOLTAGE-Vin
Efficiency
EFFICIENCY
50
40
30
5
90
80
70
60
50
4
Iout =1mA
3mA
10mA
VRp-p
RIPPLE VOLTAGE
20
10
0
3
0
1
Vin (V)
2
3
0
1
2
Vin (V)
3
4
5
5- 5
VRp-p (mV)
RIPPLE VOLTAGE (mA)
EFFICIENCY (%)
Efficiency
Vout (V)
VRp-p (mV)
RIPPLE VOLTAGE (mA)
Efficiency (%)
EFFICIENCY (%)
Vout (V)
VRp-p (mV)
RIPPLE VOLTAGE (mA)
Efficiency (%)
EFFICIENCY (%)
Vout (V)
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