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.
■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, EMP8, SSOP14
NJM2374AE
NJM2374AM
NJM2374AV
*Ta =25°C. At low temperature, the minimum voltage is 3.0V.
■PIN CONFIGURATION
1
8
2
7
3
6
4
5
PIN FUNCTION
1.CS
5.IN+
2.ES
6.V+
3.CT
7.SI
4.GND
8.CD
NJM2374AD
NJM2374AM
NJM2374AE
1
14
2
13
3
12
4
11
5
10
6
9
7
8
PIN FUNCTION
8.IN+
1.CS
2.NC
9.NC
3.ES
10.V+
4.NC
11.NC
5.CT
12.SI
6.NC
13.NC
7.GND
14.CD
NJM2374AV
Ver.2007-06-08
-1-
NJM2374A
■BLOCK DIAGRAM
CS
1
Q
S
8
CD
7
SI
6
V+
5
IN+
PWM
Logic
1.5A
R
160Ω
ES
2
Vth=300mV
Maximum
ON duty 9:1
OSC BLOCK
Ipk Sense
CT
3
PWM COMP
GND
Vref
1.25V
±2%
4
ERR.AMP
(DIP8, DMP8, EMP8: PACKAGE)
CS
1
NC
2
Q
S
PWM
Logic
1.5A
R
14
CD
13
NC
12
SI
11
NC
10
V+
9
NC
8
IN+
160Ω
ES
3
Vth=300mV
NC
4
CT
5
Maximum
ON duty 9:1
OSC BLOCK
Ipk Sense
PWM COMP
NC
GND
6
7
Vref
1.25V
±2%
ERR.AMP
(SSOP14: PACKAGE)
-2-
Ver.2007-06-08
NJM2374A
■ABSOLUTE MAXIMUM RATINGS (Ta=25°C )
PARAMETER
SYMBOL
Maximum Supply Voltage
V+
Output Switch Current
Output Switch Voltage
RATINGS
40
(NJM2374AE: 48V)
1.5
40
(NJM2374AE: 48V)
-0.3 ~ 40
(NJM2374AE: 48V)
(DIP8)
875
(DMP8)
750 (note1)
(EMP8)
1,000 (note1)
(SSOP14)
375
-40 ~ +85
-50 ~ +150
ISW
VSW
Comparator Input Voltage
VIR
Power Dissipation
PD
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).
■POWER DISSIPATION vs. AMBIENT TEMPERATURE
(Topr=-40 to +85°C,Tj= to +150°C)
Power Dissipation PD (mW)
1200
NJM2374AE
At on PC board
1000
NJM2374AD
800
600
NJM2374AM
At on PC board
400
NJM2374AV
200
0
25
50
75
100
Ambient Temperature Ta (°C)
In the case of SSOP packaging, the power dissipation should carefully
be considered when designing this parts.
Ver.2007-06-08
-3-
NJM2374A
■ELECTRICAL CHARACTERISTICS
DC Characteristics (V+=5V, Ta=25°C)
PARAMETER
SYMBOL
ICC1
ICC2
TEST CONDITIONS
+
+
TYP.
MAX.
UNIT
–
–
2.8
3.4
4.0
4.5
mA
mA
20
180
0.5
9
30
300
–
–
µA
µA
VP-P
–
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
Ichg
Idis
VOSC
Iratio
SI=V+
12
110
–
–
Vipk
Ichg=Idis
250
300
350
mV
Vsat1
–
1.0
1.3
V
Saturation Voltage 2
Vsat2
Darlington Connection
(CS=CD), ISW=0.7A
ISW=0.7A, Ic(driver)=50mA
(Forced β≈14)
–
0.5
0.7
V
Output Transistor
Bias Resistance
DC Voltage Gain
Collector Off-State
Current
Threshold Voltage
Input Bias Current
Rbias
–
160
–
Ω
35
–
120
10
–
–
–
nA
1.225
–
1.250
40
1.275
400
V
nA
hFE
IC(Off)
Vth
IIB
CT=1nF, SI=V , IN > Vth, ES=GND
V+=48V, CT=1nF, SI=V+,
IN+> Vth, ES=GND
MIN.
ISW=0.7A, VCE=5.0V
VCE=40V
(NJM2374AE: VCE=48V)
IN+=0V
(note) Output switch tests are performed under pulsed conditions to minimize power dissipation.
■TIMING CHART
High Voltage
Detect
Current-Limit
Active Point
Reference
Voltage
Output
Voltage
Oscillator
Waveform
OSC Block to
FF Reset
HIGH
LOW
Collector-Emitter
Voltage
OFF
ON
-4-
Ver.2007-06-08
NJM2374A
■TIPICAL CHARACTERISTICS
Switch ON/OFF Time
tON / tOFF (µS)
Oscillator Frequency
f OSC (kHz)
1000
Switch ON/OFF Time vs. Timing Capacitor
+
+
(V =5V,SI=V ,Pin5=GND,Ta=25°C)
1000
Oscillator Frequency vs. Timing Capacitor
+
+
(V =5V,SI=V ,Pin5=GND,Ta=25°C)
100
10
2
1000
Timing Capacitor CT (pF)
1
0.5
0
Operating Current ICC (mA)
4
tOFF
1000
10000
Timing Capacitor CT (pF)
1.5
0.5
1
1.5
Collector Current IC (A)
10
10000
Saturation Voltage 1 vs. Collector Current
+
(V =5V,CS=CD,Ta=25°C)
0
tON
1
100
Saturation Voltage 2 Vsat2 (V)
Saturation Voltage 1 Vsat1 (V)
1
100
100
Saturation Voltage 2 vs. Collector Current
+
(V =5V,Ic(driver)=50mA,β=14,Ta=25°C)
2
1.5
1
0.5
0
2
0
0.5
1
1.5
Collector Current IC (A)
2
Operating Current vs. Operating Voltage
+
+
(CT=1nF,SI=V ,IN >Vth,ES=GND,Ta=25°C)
3
2
1
0
0
5
10
15
20
25
30
35
40
+
Operating Voltage V (V)
Ver.2007-06-08
-5-
NJM2374A
■TIPICAL CHARACTERISTICS
Threshold Voltage vs. Temperature
+
(V =5V)
10
Discharge to Charge Current
Ratio Iratio
Threshold Voltage Vth (V)
1.3
1.28
1.26
1.24
1.22
-50 -25
0
25
50
9
8
7
6
75 100 125 150
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (°C)
Saturation Voltage 1 vs. Temperature
+
(V =5V,CS=CD,ISW =0.7A)
Saturation Voltage 2 Vsat2 (V)
Saturation Voltage 1 Vsat1 (V)
Ambient Temperature Ta (°C)
1.2
1.1
1
0.9
0.8
0.7
0.6
-50 -25
0
25
50
Discharge to Charge Current Ratio vs.
+
+
Temperature (V =5V,SI=V )
0.8
Saturation Voltage 2 vs. Temperature
+
(V =5V,ISW =0.7A,Ic(driver)=50mA,β=14)
0.6
0.4
0.2
0
-50 -25
75 100 125 150
0
25
50
75 100 125 150
Ambient Temperature Ta (°C)
Ambient Temperature Ta (°C)
Operating Current vs. Temperature
+
+
(V =5V,CT=1nF,SI=V ,IN >Vth,ES=GND)
+
Operating Current ICC
(mA)
5
4
3
2
1
0
-50 -25
0
25
50
75 100 125 150
Ambient Temperature Ta (°C)
-6-
Ver.2007-06-08
NJM2374A
■TYPICAL APPLICATIONS
Step-Down Converter
VIN=25V
RSC
0.22Ω
L1 220µH
1
8
7
VOUT=5V
2
NJM2374A
R2 3.6kΩ
5
6
4
CIN
100µF
3
R1
1.2kΩ
D1
CT
470pF
COUT
470µF
In the case of Step-Down Conversion with the internal power transistor,
the Output Voltage must be set lower than 6V.
Step-Up Converter
VIN=14V
RSC
0.22Ω
L1 180µH
D1
VOUT=30V
RC
180Ω
COUT
150µF
R2
46kΩ
8
1
7
2
NJM2374A
6
5
4
3
CIN
100µF
CT
1500pF
R1
2kΩ
Inverting Converter
VIN=5V
RSC
0.22Ω
D1
8
1
7
NJM2374A
R2 1.2kΩ
6
5
4
CIN
100µF
VOUT=-5V
2
3
CT
680pF
L1
100µH
R1
3.6kΩ
COUT
1000µF
In the case of Inverting Conversion with the internal power transistor,
the Output Voltage must be set lower than -6V.
D1 use to schottky diode.
In the case of SSOP packaging, the power dissipation should carefully
be considered when designing this parts.
Ver.2007-06-08
-7-
NJM2374A
Step-Down Converter (High Current)
VIN=20V
RSC
0.05Ω
RBE
75Ω
RBC
300Ω
2SA1010
L1 33µF
1
8
7
VOUT=10V
2
NJM2374A
R2 70kΩ
6
5
4
3
CIN
300µF
D1
CT
330pF
R1
10kΩ
COUT
300µF
Step-Up Converter (High Current)
VIN=5V
RSC
0.075Ω
L1 22µH
D1
VOUT=7V
RC1
100Ω
RC2
680Ω
COUT
940µF
R2
46kΩ
8
1
2SC3255
2
7
NJM2374A
5
6
4
CIN
940µF
3
CT
330pF
RBE
220Ω
R1
10kΩ
D1 use to schottky diode.
[CAUTION]
The specifications on this databook are only
given for information , without any guarantee
as regards either mistakes or omissions. The
application circuits in this databook are
described only to show representative usages
of the product and not intended for the
guarantee or permission of any right including
the industrial rights.
-8-
Ver.2007-06-08