NJM2392
PWM DC/DC Converter IC
■GENERAL
DESCRIPTION
The NJM2392 is a PWM DC/DC converter IC.
It features fixed frequency type PWM control for better noise
handling and to avoid intermittent oscillation observed in a
simplified controller.
It is suitable for Step-Up, Step-Down and Inverting applications.
In addition, it contains a pulse-by-pulse current limit circuit
and can be set by an external resistance.
■PACKAGE
OUTLINE
NJM2392D
NJM2392M
■FEATURES
●
Operating Voltage
3.0V to 40V
●
Wide Oscillator Frequency
1kHz to 150kHz
●
Internal High Power Transistor
1.5A max.
●
Internal Over Current Limit Circuit
●
PWM switching control
●
Bipolar Technology
●
Package Outline
NJM2392D
: DIP8
NJM2392M
: DMP8
■PIN
CONFIGURATION
■BLOCK
DIAGRAM
1
2
3
4
8
7
6
5
NJM2392D
NJM2392M
PIN FUNCTION
1. C
S
2. E
S
3. C
T
4. GND
5. IN-
6. V
+
7. S
I
8. C
D
C
S
1
Q
PWM
Logic
R
8
C
D
1.5A
160Ω
E
S
2
OSC Block
MAX
ON Duty
9:1
C
T
3
Error AMP
Vref
1.25V
S
7
S
I
Ipk Sense
300mV
6
PWM COMP
V
+
GND
4
Buffer
5
IN-
Ver.2008-08-29
-1-
NJM2392
■ABSOLUTE
MAXIMUM RATINGS (Ta=25°C)
PARAMETER
SYMBOL
Maximum Supply Voltage
V
+
Comparator Input Voltage
V
IR
Output Driver Voltage
V
C
(driver)
Output Switch Voltage
V
SW
Output Driver Current
I
C
(driver)
Output Switch Current
I
SW
Power Dissipation
Operating Temperature Range
Storage Temperature Range
P
D
Topr
Tstg
°C
°C
(note) When supply voltage is less than 40V, the absolute maximum input voltage is equal to the supply voltage.
(*1) At on PC board : 114.3mm
×
76.2mm
×
1.6mm(2 layer FR-4) : Conform to EIA/JEDEC
(*2) At on PC board :114.3mm
×
76.2mm
×
1.6mm(4 layer FR-4) : Conform to EIA/JEDEC
MAXIMUM RATINGS
40
-0.3 ~ 40 (note)
40
40
100
1.5
DIP8
875
DMP8
580 (*1)
750 (*2)
-40 ~ +85
-50 ~ +150
UNIT
V
V
V
V
mA
A
mW
■POWER
DISSIPATION vs. AMBIENT TEMPERATURE
Power Dissipation vs. Ambient Temperature
1000
(mW)
800
600
400
200
0
0
25
50
75
100
o
Ambient Temperature Ta ( C)
DMP8
At on 4 layer PC Board
At on 2 layer PC Board
(Topr=-40~+85
o
C, Tj= ~150
o
C)
DIP8
Power Dissipation P
D
-2-
Ver.2008-08-29
NJM2392
■ELECTRICAL
CHARACTERISTICS
DC Characteristics (V
+
=5V, Ta=25°C)
PARAMETER
SYMBOL
OSCILLATOR BLOCK
Oscillation Frequency
Charge Current
Discharge Current
Voltage Swing
Discharge to Charge
Current Ratio
CURRENT LIMIT
Peak Current
Sense Voltage
OUTPUT SWITCH
Saturation Voltage 1
Saturation Voltage 2
Output Transistor
Bias Resistance
DC Voltage Gain
Collector Off-State Current
ERROR AMPLIFIER
Threshold Voltage
Input Bias Current
TEST CONDITIONS
MIN.
TYP.
MAX.
UNIT
f
OSC
I
chg
I
dis
V
OSC
I
ratio
IN-=0V, C
T
=1nF
C
T
=1nF
I
chg
/I
dis
18
11
110
–
–
27
18
180
0.5
9
36
27
300
–
–
kHz
µA
µA
V
P-P
–
V
ipk
250
300
350
mV
V
sat1
V
sat2
R
bias
h
FE
I
C(Off)
Darlington Connection
(C
S
=C
D
), I
SW
=0.7A
I
SW
=0.7A, I
C
(driver)=50mA
(Forced
β≈14)
–
–
–
1.0
0.5
160
120
0.01
1.3
0.7
–
–
1
V
V
Ω
–
µA
I
SW
=0.7A,V
CE
=5.0V
V
CE
=40V
35
–
V
th
I
IB
IN-=0V
1.225
–
1.250
300
1.275
900
V
nA
GENERAL CHARACTERISTICS
Operating Current
I
CC
C
T
=1nF, S
I
=V
+
, IN->V
th
, E
S
=GND
–
2.8
4.0
mA
(note) Output switch tests are performed under pulsed conditions to minimize power dissipation.
Ver.2008-08-29
-3-
NJM2392
■TYPICAL
APPLICATIONS
Step-Down Converter
V
IN
R
SC
L1
7
8
1
2
C1
5
R2
C
IN
C
T
D1
R1
V
OUT
NJM2392
6
4
3
C
OUT
Step-Up Converter
V
IN
R
SC
L1
D1
V
OUT
R
C
C
OUT
C1
R2
7
8
1
2
NJM2392
6
C
IN
4
3
5
C
T
R1
Inverting Converter
V
IN
R
SC
D1
7
8
1
2
C1
3
C
T
5
R2
L1
R1
V
OUT
NJM2392
6
C
IN
4
C
OUT
D1 use to schottky diode.
-4-
Ver.2008-08-29
NJM2392
■
TYPICAL APPLICATIONS
Step-Down Converter (High Current)
V
IN
R
SC
R
BE
R
BC
L1
7
8
1
2
C1
5
R2
C
IN
C
T
F
D1
R1
V
OUT
NJM2392
6
4
3
C
OUT
Step-Up Converter (High Current)
R
SC
V
IN
L1
D1
V
OUT
R
C2
R
C1
C
OUT
C1
R2
7
8
1
2
NJM2392
6
C
IN
4
C
T
3
5
R
BE
R1
D1 use to schottky diode.
Ver.2008-08-29
-5-
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