elm612da

ELM612DA 3A 36V PWM step down DC/DC converter
■General description
ELM612DA is a of step-down switching regulator with PWM control, reference voltage source, oscillation
circuit, error amplifier, internal PMOS, etc. ELM612DA provides low-ripple power, high efficiency, and
excellent transient characteristics; PWM control circuit is able to vary the duty ratio linearly from 0 up to 100%.
ELM612DA also contains error amplifier circuit as well as soft-start circuit that prevents overshoot at during
startup. Internal enable function, over current protect function and short circuit protect function will reduce the
operation frequency from 150kHz to 30kHz when overmuch current or short circuit occurs. Meanwhile, internal
compensation block is able to minimize the quantity of required external component. With internal P-channel
Power MOS, and externally connected coil, capacitor, and diode, ELM612DA is able to function as stepdown switching regulator. By the small package of SOP-8, ELM612DA is capable of working as ideal power
supply units for many devices while providing outstanding features such as low current consumption. Since this
converter accommodates input voltage up to 36V, ELM612DA is also suitable for AC adapter applications.
■Features
■Application
• Input voltage
: 5.5V to 36V
• Output voltage
: 0.8V to Vin
• Output current
: 3.0A
• Duty ratio
: 0% to 100%
• Constant frequency
: Typ.150kHz
• Soft-start
• Thermal shutdown protection
• Short circuit protection
• Built-in internal P-channel MOS
• Package
: SOP-8
•
•
•
•
•
•
•
•
•
PC motherboard
LCD monitor
Graphic card
DVD, Blu-ray player
Telecom equipment
ADSL modem
Printer and other peripheral equipment
Microcomputer power supply
Network power supply
■Maximum absolute ratings
Parameter
VIN power supply voltage
Apply voltage to FB
Apply voltage to EN
Apply voltage to SW
Apply voltage to VC
Power dissipation
Operating temperature range
Storage temperature range
Symbol
Vin
Vfb
Ven
Vsw
Vc
Pd
Top
Tstg
Limit
-0.3 to +40
GND-0.3 to Vin
GND-0.3 to Vin+0.3
GND-0.3 to Vin+0.3
Vin-20 to Vin+0.3
300
-40 to +85
-65 to +150
Caution: Permanent damage to the device may occur when ratings above maximum absolute ones are used.
8- 1
Unit
V
V
V
V
V
mW
°C
°C
Rev.1.1
ELM612DA 3A 36V PWM step down DC/DC converter
■Selection guide
ELM612DA-N
Symbol
a
b
c
Package
Product version
Taping direction
ELM612DA - N
↑↑ ↑
ab c
D: SOP-8
A
N: Refer to PKG file
* Taping direction is one way.
■Pin configuration
SOP-8(TOP VIEW)
8
7
6
5
Pin No.
1
2
3
4
1
2
3
4
5, 6
7, 8
Pin name
Pin description
FB
Feedback(0.82V operation)
Enable / Disable
EN
H: Normal operation mode.(Step-down operation)
L: Shutdown mode.(All circuits deactivated)
Add an external capacitor to VIN.
VC
The voltage is set to Vin -7V
VIN
IC power supply
Switch. Connect external inductor/diode to here.
SW
Minimize trace area at this pin to reduce EMI.
GND
GND
■Standard circuit
VIN
FB
ELM612DA
24V +
-
EN
Cc=
0.1µF/16V
VC
L=47µH
SW
GND
Cin=330µF/50V
Cout=
330µF/16V
D=5A/40V
Vout
R1
R2
Vout=Vfb(1+R1/R2)
8- 2
Rev.1.1
ELM612DA 3A 36V PWM step down DC/DC converter
■Block diagram
Vin
VC
Oscillation circuit
SW
PWM
control circuit
Thermal
shutdown
protection
■Electrical characteristics
EN pin input voltage (*1)
Feedback voltage
Feedback bias current
Current limit
Quiescent current (switch off)
Current consumption
during power off
Voltage clamp
Oscillation frequency
Frequency of current limit
or short circuit protect
Reference
voltage source
and soft start
EN
GND
Parameter
Input voltage
FB
Error
amplifier
Symbol
Vin
Venh
Venl
Vfb
Ifb
Icl
Ignd
Vin=24V, Top=25°C, unless otherwise specified
Condition
Min.
Typ.
Max. Unit
5.5
36.0
V
Evaluate oscillation at SW pin
2.0
V
Evaluate oscillation stop at SW pin
0.8
Iout=0.1A
0.803 0.820 0.836
V
Iout=0.1A
0.1
0.5
µA
2.0
A
EN ≥ Ven_h, Vfb=1V
1
2
mA
1
10
µA
Vin-6
120
Vin-7
150
Vin-8
180
V
kHz
20
30
40
kHz
1
2
%
0.2
0.5
%
80
87
100
mΩ
%
50
μS
Ignd_off EN ≤ Ven_l
Vc
Fosc
No load
Foscl
ΔVout
Vin=12V to 36V, Iout=0.2A
Vout
ΔVout
Load regulation
Iout=0.1 to 1.3A
Vout
Internal MOSFET Rdson
Rds(on) Vfb=0V, Iout=1A
Efficiency
η
Vin=24V, Vout=5V, Iout=3.0A
(*1) : Rise time and fall time of the EN pin use under the following conditions, please.
EN pin rise time & fall time
tr, tf
Ven=VenI to VenH
Line regulation
8- 3
Rev.1.1
ELM612DA 3A 36V PWM step down DC/DC converter
■Application notes
PWM Control
ELM612DA is DC/DC converter which consists pulse-width modulation (PWM) system. In converters of
ELM612DA, the pulse width varies according toe the load current, within the range from 0 to 100%. The ripple
voltage produced by switching can easily be removed through the filter since switching frequency remains constant; ELM612DA is capable of providing low-ripple power within broad ranges of input voltage and load current.
■Test circuits
4
2
Cc=
0.1�F
Vin
Cin=
330�F
3
VIN
FB
EN
SW
1
L=47�H
ELM612DA
VC
Vout
5, 6
R1
GND
7, 8
RL
D
Cout=
330�F
C1
C2
R2
■Marking
SOP-8
ELM
612DA
abc
Mark
ELM612DA
Content
Product name
abc
Assembly lot No.:
000 to 999 repeated
8- 4
Rev.1.1
ELM612DA 3A 36V PWM step down DC/DC converter
■Typical characteristics
• Vout=3.3V :
Cin=330µF, Cout=330µF, R1=4kΩ, R2=1.3kΩ, C1=0.1μF, C2=0.1μF, L=47µH,
• D=5A/40V,
V=3.3V Top=25°C
Vout-Iout
3.4
EFFICIENCY-Iout
100
Vin=12V
Vin=6V
Vin=12V
3.1
4.0
10
1
100
Iout (mA)
1000
Vin=24V
40
20
0
0.1
10000
1
10
1000
10000
Start Response
Vout-Vin
Ven=2V, Vin=12V, No load
4
Iout=1mA
Iout=100mA Iout=1A
3
2
1
Iout=10mA
2.0
100
Iout (mA)
3.0
Vout (V)
Vin=6V
60
Vout (V)
3
80
0
2
1.0
1
0
0
4
8
0
12 16 20 24 28 32 36
Vin (V)
8- 5
1
2
Time (ms)
3
Ven (V)
Vout (V)
3.2
EFFICIENCY (%)
Vin=24V
3.3
4
Rev.1.1
ELM612DA 3A 36V PWM step down DC/DC converter
Load Transient Response
4
Vin=12V, Iout=100mA�1A
4
3.5
Vout (V)
3
2.5
3.5
3
2.5
1
0.5
0.5
0
5
0
10
Time (ms)
15
Iout (A)
1
0
20
0
5
10
Time (ms)
15
Iout (A)
Vout (V)
Load Transient Response
Vin=12V, Iout=10mA�1A
20
Vfb-Top
Vin=12V, Iout=0.1A
0.82
0.81
Vfb (V)
0.8
0.79
0.78
0.77
0.76
-40
-20
0
20
40
60
80
Top (�)
8- 6
Rev.1.1
ELM612DA 3A 36V PWM step down DC/DC converter
• Vout=5.0V :
Cin=330µF, Cout=330µF, R1=6.8kΩ, R2=1.3kΩ, C1=0.1μF, C2=0.1μF, L=47µH,
• D=5A/40V,
V=5.0V Top=25°C
Vout-Iout
5.2
Vin=12V
EFFICIENCY (%)
Vin=24V
5.1
Vin=12V
4.8
Vin=6V
4.7
4.6
6.0
10
1
100
Iout (mA)
1000
80
60
Vin=24V
40
20
0
0.1
10000
1
10
100
1000
10000
Iout (mA)
Start Response
Vout-Vin
Ven=2V, Vin=12V, No load
Iout=1mA
5
5.0
4
Iout=100mA
4.0
Iout=10mA
Vout (V)
Vout (V)
Vin=6V
Iout=1A
3.0
3
2
1
0
2.0
2
1.0
1
0
0
4
8
0
12 16 20 24 28 32 36
Vin (V)
8- 7
1
2
Time (ms)
3
Ven (V)
Vout (V)
5
4.9
EFFICIENCY-Iout
100
4
Rev.1.1
ELM612DA 3A 36V PWM step down DC/DC converter
Load Transient Response
4
10
Time (ms)
15
4
1
0.5
0.5
Iout (A)
1
0
5
5
0
20
0
5
10
Time (ms)
15
Iout (A)
5
0
Vin=12V, Iout=100mA�1A
6
Vout (V)
6
Vout (V)
Load Transient Response
Vin=12V, Iout=10mA�1A
20
Vfb-Top
Vin=12V, Iout=0.1A
0.82
0.81
Vfb (V)
0.8
0.79
0.78
0.77
0.76
-40
-20
0
20
40
60
80
Top (�)
8- 8
Rev.1.1
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