NJM2374A
PWM DC/DC CONVERTER IC
■GENERAL
DESCRIPTION
■PACKAGE
OUTLINE
The
NJM2374A
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
NJM2374AD
for EMI sensitive application.
( DIP8 )
■FEATURES
●Operating
Voltage
(2.5V* to 40V)
●NJM2374AE
Operating Voltage
(2.5V* to 48V)
●Wide
Oscillator Frequency
(100Hz to 100kHz)
●Internal
High Power Transistor
1.5A (max.)
●Internal
Over Current Limit Circuit
●PWM
form Switching Power Supply Control
●Bipolar
Technology
●Package
Outline
DIP8, DMP8, SOP8 JEDEC 150mil
SSOP14
*Ta =25°C. At low temperature, the minimum voltage is 3.0V.
NJM2374AM
( DMP8 )
NJM2374AE
( SOP8 )
NJM2374AV
( SSOP14 )
■PIN
CONFIGURATION
1
8
2
7
3
6
PIN FUNCTION
1. C
S
5. IN
+
2. E
S
6. V
+
3. C
T
7. S
I
4. GND
8. C
D
4
5
NJM2374AD
NJM2374AM
NJM2374AE
1
2
3
4
5
6
7
14
13
12
11
10
9
8
PIN FUNCTION
8. IN
+
1. C
S
2. NC
9. NC
3. E
S
10. V
+
4. NC
11. NC
5. C
T
12. S
I
6. NC
13. NC
7. GND
14. C
D
NJM2374AV
Ver.2011-12-08
-1-
NJM2374A
■BLOCK
DIAGRAM
C
S
1
Q
1.5A
160Ω
PWM
Logic
S
8
C
D
R
E
S
2
Vth=300mV
Maximum
ON duty 9:1
OSC BLOCK
Ipk Sense
7
S
I
C
T
3
PWM COMP
6
V
+
GND
4
Vref
1.25V
±2%
ERR.AMP
5
IN
+
(DIP8, DMP8, SOP8: PACKAGE)
C
S
1
Q
1.5A
160Ω
PWM
Logic
S
14
C
D
NC
2
R
13
NC
E
S
3
Vth=300mV
12
S
I
NC
4
Maximum
ON duty 9:1
OSC BLOCK
Ipk Sense
11
NC
C
T
5
PWM COMP
10
V
+
NC
6
Vref
1.25V
±2%
ERR.AMP
9
NC
GND
7
8
IN
+
(SSOP14: PACKAGE)
-2-
Ver.2011-12-08
NJM2374A
■ABSOLUTE
MAXIMUM RATINGS
PARAMETER
SYMBOL
Maximum Supply Voltage
V
+
Output Switch Current
Output Switch Voltage
Comparator Input Voltage
Power Dissipation
P
D
I
SW
V
SW
V
IR
(Ta=25°C )
UNIT
V
A
V
V
mW
Operating Temperature Range
Topr
°C
Storage Temperature Range
Tstg
°C
(note1) At on PC board.
In the case of Step-Down and Inverting Conversion with the internal power transistor,
the Output Voltage must be set lower than 6V(-6V).
RATINGS
40
(NJM2374AE: 48V)
1.5
40
(NJM2374AE: 48V)
-0.3 ~ 40
(NJM2374AE: 48V)
(DIP8)
875
(DMP8)
750 (note1)
(SOP8)
1,000 (note1)
(SSOP14)
375
-40 ~ +85
-50 ~ +150
■POWER
DISSIPATION vs. AMBIENT TEMPERATURE
(Topr=-40 to +85°C,Tj= to +150°C)
1200
1000
800
600
400
200
0
25
50
NJM2374AV
NJM2374AE
At on PC board
Power Dissipation P
D
(mW)
NJM2374AD
NJM2374AM
At on PC board
75
100
Ambient Temperature Ta (°C)
In the case of SSOP packaging, the power dissipation should carefully
be considered when designing this parts.
Ver.2011-12-08
-3-
NJM2374A
■ELECTRICAL
CHARACTERISTICS
DC Characteristics (V
+
=5V, Ta=25°C)
PARAMETER
SYMBOL
Operating Current 1
Operating Current 2
(NJM2374AE Only)
Charge Current
Discharge Current
Voltage Swing
Discharge to Charge
Current Ratio
Peak Current
Sense Voltage
Saturation Voltage 1
Saturation Voltage 2
Output Transistor
Bias Resistance
DC Voltage Gain
Collector Off-State
Current
Threshold Voltage
Input Bias Current
I
CC1
I
CC2
I
chg
I
dis
V
OSC
I
ratio
V
ipk
V
sat1
V
sat2
R
bias
h
FE
I
C(Off)
V
th
I
IB
I
SW
=0.7A, V
CE
=5.0V
V
CE
=40V
(NJM2374AE: V
CE
=48V)
IN =0V
+
TEST CONDITIONS
MIN.
–
–
12
110
–
–
250
–
–
–
35
–
1.225
–
TYP.
2.8
3.4
20
180
0.5
9
300
1.0
0.5
160
120
10
1.250
40
MAX.
4.0
4.5
30
300
–
–
350
1.3
0.7
–
–
–
1.275
400
UNIT
mA
mA
µA
µA
V
P-P
–
mV
V
V
Ω
–
nA
V
nA
C
T
=1nF, S
I
=V
+
, IN
+
> V
th
, E
S
=GND
V
+
=48V, C
T
=1nF, S
I
=V
+
,
IN
+
> V
th
, E
S
=GND
S
I
=V
+
I
chg
=I
dis
Darlington Connection
(C
S
=C
D
), I
SW
=0.7A
I
SW
=0.7A, Ic(driver)=50mA
(Forced
β≈14)
(note) Output switch tests are performed under pulsed conditions to minimize power dissipation.
■TIMING
CHART
High Voltage
Detect
Reference
Voltage
Output
Voltage
Oscillator
Waveform
HIGH
LOW
Collector-Emitter
Voltage
OFF
ON
Current-Limit
Active Point
OSC Block to
FF Reset
-4-
Ver.2011-12-08
NJM2374A
■TYPICAL
CHARACTERISTICS
Oscillator Frequency vs. Timing Capacitor
+
+
(V =5V,S
I
=V ,Pin5=GND,Ta=25°C)
1000
Switch ON/OFF Time vs. Timing Capacitor
+
+
(V =5V,S
I
=V ,Pin5=GND,Ta=25°C)
1000
Switch ON/OFF Time
t
ON
/ t
OFF
(µS)
Oscillator Frequency
f
OSC
(kHz)
100
100
t
ON
10
10
t
OFF
1
100
1000
Timing Capacitor C
T
(pF)
10000
1
100
1000
Timing Capacitor C
T
(pF)
10000
Saturation Voltage 1 V
sat1
(V)
1.5
1
0.5
0
0
0.5
1
1.5
Collector Current I
C
(A)
2
Saturation Voltage 2 V
sat2
(V)
2
Saturation Voltage 1 vs. Collector Current
+
(V =5V,C
S
=C
D
,Ta=25°C)
2
1.5
1
0.5
0
Saturation Voltage 2 vs. Collector Current
+
(V =5V,Ic(driver)=50mA,β=14,Ta=25°C)
0
0.5
1
1.5
Collector Current I
C
(A)
2
Operating Current I
CC
(mA)
4
3
2
1
0
Operating Current vs. Operating Voltage
+
+
(C
T
=1nF,S
I
=V ,IN >V
th
,E
S
=GND,Ta=25°C)
0
5
10
15
20
25
30
+
35
40
Operating Voltage V (V)
Ver.2011-12-08
-5-
嵌入式系统
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