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Электронный компонент: R1223N152A

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PWM/VFM step-down DC/DC Converter
R1223N Series
`
99.12.8
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Rev. 1.11 - 1 -
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OUTLINE

The R1223N Series are PWM step-down DC/DC Converter controllers with low supply current by CMOS

process.
Each of these ICs consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier,
a soft-start circuit, a protection circuit, a PWM/VFM alternative circuit, a chip enable circuit, and resistors for
voltage detection. A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC
with only four external components, or a power-transistor, an inductor, a diode and a capacitor.
With a PWM/VFM alternative circuit, when the load current is small, the operation is automatically switching
into the VFM oscillator from PWM oscillator, therefore the efficiency at small load current is improved. The
R1223N XXXB type, which is without a PWM/VFM alternative circuit, is also available.
If the term of maximum duty cycle keeps on a certain time, the embedded protection circuit works. There are
two types of protection function. One is latch-type protection circuit, and it works to latch an external Power
MOSFET with keeping it disable. To release the condition of protection, after disable this IC with a chip enable
circuit, enable it again, or restart this IC with power-on. The other is Reset-type protection circuit, and it works to
restart the operation with soft-start and repeat this operation until maximum duty cycle condition is released.
Either of these protection circuits can be designated by users' request.
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FEATURES
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Range of Input Voltage
2.3V
~
13.2V
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Built-in Soft-start Function and Two choices of Protection Function (Latch-type or Reset type)
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Two choices of Oscillator Frequency
300kHz, 500kHz
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High Efficiency
TYP. 90%
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Output Voltage
Stepwise Setting with a step of 0.1V
in the range of 1.5V
~
5.0V
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Standby Current
TYP. 0A
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High Accuracy Output Voltage
2.0%
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Low Temperature-Drift Coefficient of Output Voltage
TYP. 100ppm/
C
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APPLICATIONS
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Power source for hand-held communication equipment, cameras, video instruments such as VCRs,
camcorders.
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Power source for battery-powered equipment.
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Power source for household electrical appliances.
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Rev. 1.11 - 2 -
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BLOCK DIAGRAM
OSC
V
IN
EXT
GND
V
OUT
Vref
CE
Chip Enable
Soft Start
Protection
PWM/VFM
CONTROL
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SELECTION GUIDE
In the R1223N Series, the output voltage, the oscillator frequency, the optional function, and the taping type for
the ICs can be selected at the user
'
s request.
The selection can be made by designating the part number as shown below;
R1223NXXXX-XX
-
-
-
-
a
b
c
d
Code
Contents
a
Setting Output Voltage(V
OUT
):
Stepwise setting with a step of 0.1V in the range of 1.5V to 5.0V is possible.
b
Designation of Oscillator Frequency
2 : fixed
c
Designation of Optional Function
A : 300kHz, with a PWM/VFM alternative circuit, Latch-type protection
B : 500 kHz, with a PWM/VFM alternative circuit, Latch-type protection
C : 300kHz, without a PWM/VFM alternative circuit, Latch-type protection
D : 500kHz, without a PWM/VFM alternative circuit, Latch-type protection
E : 300kHz, with a PWM/VFM alternative circuit, Reset-type protection
F : 500 kHz, with a PWM/VFM alternative circuit, Reset-type protection
G : 300kHz, without a PWM/VFM alternative circuit, Reset-type protection
H : 500kHz, without a PWM/VFM alternative circuit, Reset-type protection
d
Designation of Taping Type; Ex. :TR,TL(refer to Taping Specification)
"TR" is prescribed as a standard.
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Rev. 1.11 - 3 -
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PIN CONFIGURATION
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SOT-23-5
1
2
3
4
V
IN
EXT
CE GND
V
OUT
(mark side)
5
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PIN DESCRIPTION
Pin No.
Symbol
Description
1
CE
Chip Enable Pin
2
GND
Ground Pin
3
V
OUT
Pin for Monitoring Output Voltage
4
EXT
External Transistor Drive Pin
5
V
IN
Power Supply Pin
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ABSOLUTE MAXIMUM RATINGS
Symbol
Item
Rating
Unit
V
IN
V
IN
Supply Voltage
15
V
V
EXT
EXT Pin Output Voltage
-0.3
~
V
IN
+0.3
V
V
CE
CE Pin Input Voltage
-0.3
~
V
IN
+0.3
V
V
OUT
V
OUT
Pin Input Voltage
-0.3
~
V
IN
+0.3
V
I
EXT
EXT Pin Inductor Drive Output Current
25
mA
PD
Power Dissipation
250
mW
Topt
Operating Temperature Range
-40
~
+85
C
Tstg
Storage Temperature Range
-55
~
+125
C
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Rev. 1.11 - 4 -
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ELECTRICAL CHARACTERISTICS
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R1223N**2A(,C,E,G) Output Voltage : Vo
(Topt=25
C)
Symbol
Item
Conditions
MIN.
TYP.
MAX. Unit
V
IN
Operating Input Voltage
2.3
13.2
V
V
OUT
Step-down Output Voltage
V
IN
=V
CE
=Vo+1.2V,I
OUT
=-10mA
Vo
0.98
Vo
Vo
1.02
V
D
V
OUT
/
D
T
Step-down Output Voltage
Temperature Coefficient
-40
C
Topt
85
C
100
ppm
/
C
fosc
Oscillator Frequency
V
IN
=V
CE
=Vo+1.2V,I
OUT
=-100mA
240
300
360
kHz
D
f
OSC
/
D
T
Oscillator Frequency
Temperature Coefficient
-40
C
Topt
85
C
0.3
%
/
C
I
DD1
Supply Current1
V
IN
=13.2V,V
CE
=13.2V,V
OUT
=13.2V
100
160
m
A
I
stb
Standby Current
V
IN
=13.2V,V
CE
=0V,V
OUT
=0V
0
0.5
m
A
I
EXTH
EXT "H" Output Current
V
IN
=8V,V
EXT
=7.9V,V
OUT
=8V,V
CE
=8V
-10
-6
mA
I
EXTL
EXT "L" Output Current
V
IN
=8V,V
EXT
=0.1V,V
OUT
=0V,V
CE
=8V
10
20
mA
I
CEH
CE "H" Input Current
V
IN
=13.2V,V
CE
=13.2V,V
OUT
=13.2V
0
0.5
m
A
I
CEL
CE "L" Input Current
V
IN
=13.2V,V
CE
=0V,V
OUT
=13.2V
-0.5
0
m
A
V
CEH
CE "H" Input Voltage
V
IN
=8V,V
OUT
=0V
1.5V
0.8
1.2
V
V
CEL
CE "L" Input Voltage
V
IN
=8V,V
OUT
=1.5V
0V
0.3
0.8
V
Maxdty Oscillator Maximum Duty Cycle
100
%
VFMdty VFM Duty Cycle
only for A, E version
25
%
T
start
Delay Time by Soft-Start function
V
IN
= Vo+1.2V, V
CE
=0V
Vo+1.2V
specified at 80% for rising edge
5
10
16
ms
T
prot
Delay Time for protection circuit
V
IN
=V
CE
=Vo+1.2V
V
OUT
= Vo+1.2V
0V
1
3
5
ms
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Rev. 1.11 - 5 -
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R1223N**2B(,D,F,H) Output Voltage : Vo (Topt=25
C)
Symbol
Item
Conditions
MIN.
TYP.
MAX. Unit
V
IN
Operating Input Voltage
2.3
13.2
V
V
OUT
Step-down Output Voltage
V
IN
=V
CE
=Vo+1.2V,I
OUT
=-10mA
Vo
0.98
Vo
Vo
1.02
V
D
V
OUT
/
D
T
Step-down Output Voltage
Temperature Coefficient
-40
C
Topt
85
C
100
ppm
/
C
fosc
Oscillator Frequency
V
IN
=V
CE
=Vo+1.2V,I
OUT
=-100mA
400
500
600
kHz
D
f
OSC
/
D
T
Oscillator Frequency
Temperature Coefficient
-40
C
Topt
85
C
0.3
%
/
C
I
DD1
Supply Current1
V
IN
=13.2V,V
CE
=13.2V,V
OUT
=13.2V
140
200
m
A
I
stb
Standby Current
V
IN
=13.2V,V
CE
=0V,V
OUT
=0V
0
0.5
m
A
I
EXTH
EXT "H" Output Current
V
IN
=8V,V
EXT
=7.9V,V
OUT
=8V,V
CE
=8V
-10
-6
mA
I
EXTL
EXT "L" Output Current
V
IN
=8V,V
EXT
=0.1V,V
OUT
=0V,V
CE
=8V
10
20
mA
I
CEH
CE "H" Input Current
V
IN
=13.2V,V
CE
=13.2V,V
OUT
=13.2V
0
0.5
m
A
I
CEL
CE "L" Input Current
V
IN
=13.2V,V
CE
=0V,V
OUT
=13.2V
-0.5
0
m
A
V
CEH
CE "H" Input Voltage
V
IN
=8V,V
OUT
=0V
1.5V
0.8
1.2
V
V
CEL
CE "L" Input Voltage
V
IN
=8V,V
OUT
=1.5V
0V
0.3
0.8
V
Maxdty Oscillator Maximum Duty Cycle
100
%
VFMdty VFM Duty Cycle
only for B, F version
25
%
T
start
Delay Time by Soft-Start function
V
IN
= Vo+1.2V, V
CE
=0V
Vo+1.2V
specified at 80% for rising edge
3
6
10
ms
T
prot
Delay Time for protection circuit
V
IN
=V
CE
=Vo+1.2V
V
OUT
= Vo+1.2V
0V
1
2
4
ms