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 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
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 ↑↑↑ ↑ abc 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 Symbol Vin Vst Vhold Iss Vout Ilx Ilxl Fosc Duty L=220μH, D=MA721, C=47μF, Vss=0V, Top=25°C Condition Min. Typ. Max. Unit 10 V RL=27kΩ 0.98 V Iout=1mA 0.7 V Vin=1.5V 9.0 18.0 μA Iout=1mA, Vin=1.5V 2.63 2.70 2.77 V Vout=2.6V, Vlx=0.4V 70 mA Vout=Vlx=10V 1.0 μA Vout=2.6V 35 55 75 kHz 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 Symbol Vin Vst Vhold Iss Vout Ilx Ilxl Fosc Duty L=220μH, D=MA721, C=47μF, Vss=0V, Top=25°C Condition Min. Typ. Max. Unit 10 V RL=33kΩ 0.98 V Iout=1mA 0.7 V Vin=1.5V 14.0 23.0 μA Iout=1mA, Vin=1.5V 3.21 3.30 3.39 V Vout=3.2V, Vlx=0.4V 80 mA Vout=Vlx=10V 1.0 μA Vout=3.2V 35 55 75 kHz 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 Symbol Vin Vst Vhold Iss Vout Ilx Ilxl Fosc Duty
L=220μH, D=MA721, C=47μF, Vss=0V, Top=25°C Condition Min. Typ. Max. Unit 10 V RL=50kΩ 0.98 V Iout=1mA 0.9 V Vin=3V 30.0 45.0 μA Iout=1mA, Vin=3V 4.87 5.00 5.13 V Vout=4.8V, Vlx=0.4V 110 mA Vout=Vlx=10V 1.0 μA Vout=4.8V 35 55 75 kHz 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 .1V 6 * 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
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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 recommends 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 output 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)