NJM2378
-
1
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Ver.2012-02-20
NJM2378M
(DMP8)
PWM SWITCHING REGULATOR CONTROL IC FOR SLAVE TYPE
■ GENERAL DESCRIPTION ■ PACKAGE OUTLINE
The NJM2378 is a high speed switching regulator control
IC, and directly drive an external Bipolar Transistor to use
internal totempole output circuit.
The NJM2378 operate slave mode which synchronous
external oscillation frequency, and the slave mode reduce
the total noise.
The NJM2378 is suitable for flyback type switching
regulation up to 10W and several output power supply for
LCD panel.
■ FEATURES
● Operating Voltage (3.6 to 32V)
● Reference Voltage (2.5V±2%)
● Input Outside
Oscillator Frequency (5 to 350 kHz)
● Output Switch Current (±8mA min.)
● Under Voltage Lockouts Circuit
● Bipolar Technology
● Package Outline DIP8, DMP8, SOP8 JEDEC 150mil, SSOP8
■ BLOCK DIAGRAM
NJM2378D
(DIP8)
NJM2378E
(
SOP8
)
PIN FUNCTION
1.IN-
2.F.B
3.GND
4.OUT
5.V+
6.CS
7.CT
8.REF
NJM2378V
(
SSOP8
)
1
VREF
V+
ER⋅AMP
L.O
500Ω
U.V.LO
PWM
8 7 6 5
432
CSCT REF
IN- OUTGNDF. B
0.52V
S.C.P
30uA
NJM2378
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-Ver.2012-02-20
■ ABSOLUTE MAXIMUM RATINGS (Ta=25°C)
PARAMETER SYMBOL RATINGS UNIT
Supply Voltage V+ 36 V
Reference Output Current IOR 10 mA
Output Current IO ±50 mA
CT Pin Voltage VCT 1.5 V
Power Dissipation PD (DIP8) 700 mW
(DMP8) 300
(SOP8) 300
(SSOP8) 250
Operating Temperature Range TOPR -40 to +85 °C
Storage Temperature Range TSTG -50 to +125 °C
■ RECOMMENDED OPERATING CONDITIONS (V+=6V, Ta=25°C)
PARAMETER SYMBOL MIN. MAX. UNIT
Operating Voltage V+ 3.6 32 V
Feed Back Resistor RNF 100 - kΩ
Oscillate fOSC 5 350 kHz
INPUT WAVEFORME
PARAMETER SYMBOL RECOMMENDED UNIT
Triangle Waveform VP-P 0.5 V
Offset Voltage VOFFSET 0.5 V
NJM2378
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Ver.2012-02-20
■ ELECTRICAL CHARACTERISTICS
(V+=6V, RT=33kΩ, CT=1000pF, Ta=25°C OSC:Triangle Waveform, VP-P=0.5V, Offset=0.5V, fOSC=100kHz)
REFERENCE VOLTAGE BLOCK
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Output Voltage VREF I
OR=1mA 2.45 2.50 2.55 V
Line Regulation LINE V
+=3.6 to 32V, IOR=1mA - 6.8 20.7 mV
Load Regulation LOAD I
OR=0.1 to 5.0mA - 5 30 mV
OSCILLATOR BLOCK
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Reference Voltage VB 0.51 0.52 0.53 V
Input Bias Current IB - 5 100 nA
Open Loop Gain AV - 90 - dB
Gain Band width Product GB - 0.6 - MHz
Maximum Output Voltage VOM+ R
NF=100kΩ V
REF-0.2 - - V
(F.B Pin) VOM- R
NF=100kΩ - - 200 mV
Output Source Current IOM+ V
OM=1V 40 85 200 µA
PWM COMPARATOR BLOCK
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Triangle Waveform Input
Minimum Voltage (CT Pin)
OSCLO CT Pin Triangle Waveform Input 0 - 0.4 V
Triangle Waveform Input
Maximum Voltage (CT Pin)
OSCHI CT Pin Triangle Waveform Input 0.7 - 1.3 V
Input Threshold Voltage (F.B Pin) VTH0 duty⋅cycle=0% - 0.55 0.65 V
Input Threshold Voltage (F.B Pin) VTH50 duty⋅cycle=50% - 0.87 - V
Maximum Duty Cycle αM F.B Pin=1.2V 55 64 85 %
SOFT START CIRCUIT BLOCK
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Input Bias Current (CS Pin) IBCS - 250 650 nA
Input Threshold Voltage (CS Pin) VTHCS0 duty⋅cycle=0% - 0.25 0.35 V
Input Threshold Voltage (CS Pin) VTHCS50 duty⋅cycle=50% - 0.52 - V
NJM2378
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■ ELECTRICAL CHARACTERISTICS
(V+=6V, RT=33kΩ, CT=1000pF, Ta=25°C OSC:Triangle Waveform, VP-P=0.5V, OFFSET=0.5V, fOSC=100kHz)
SHORT CIRCUIT PROTECTION
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Input Threshold Voltage (F.B Pin) VTHPC 1.20 1.50 1.80 V
Charge Current (CS Pin) ICHG CS Pin=0V,F.B Pin=2V 10 30 50 µA
Latch mode
Threshold Voltage (CS Pin)
VTHLA 1.20 1.50 1.80 V
UNDER VOLTAGE LOCKOUT
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
ON Threshold Voltage VTHON - 2.70 - V
OFF Threshold Voltage VTHOFF - 2.52 - V
Hysteresis Voltage VHYS 60 180 - mV
OUTPUT
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
H-Output Voltage (OUT Pin) VOH R
L=10kΩ 3.50 4.00 - V
L-Output Voltage (OUT Pin) VOL Output Sink Current=20mA - 0.25 0.65 V
Output Source Current (OUT Pin) ISOURCE OUT Pin=0V 8 11 - mA
GENERAL CHARACTERISTICS
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Quiescent Current ICCLA Latch Mode - 1.6 2.2 mA
Average Quiescent Current ICCAV RL=∞, duty⋅cycle=50% - 3.5 4.8 mA
NJM2378
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Ver.2012-02-20
■ TYPICAL APPLICATIONS
Synchronous mode with NJM2368
External pulse mode
When Short Circuit Protection (SCP) is activated, Output terminal (Pin 4) becomes high impedance and the external
switching transistor (Q1) is turned off.
However, small leak current from Output terminal at high ambient temperature may turn on the external switching transistor
causing malfunction of the SCP particularly when FET is used as a switching device.
To avoid this issue, insert a 100kΩ resistor between the Gate and the Source of the external transistor.
GND
V
+
VOUT
Rsf Rsr Cs
1
VREF
ER⋅AMP
L.O
500Ω
U.V.LO
PWM
8 7 6 5
432
0.52V
S.C.P
30uA
GND
CIN
Q1
Rf
CLP
R1
D1
R2
COUT
N1 N2
*100kΩ
Duty 50%
L
GND
0.5V
0.5V
Input Pulse
VOUT1
8 VOUT2
NJM2378
NJM2368
7 6 5
1 2 3 4
8 7 6 5
1 2 3 4
NJM2378
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(Ta=25℃)
0
1
2
3
4
5
0 10203040
OperatingVoltageV+(V)
OperatingCurrentICC(mA)
ICCLA
ICCAV
(Ta=25℃)
2.48
2.49
2.5
2.51
2.52
0 10203040
OperatingVoltage Ｖ
+
 （Ｖ）
ReferenceVoltage Ｖ
ＲＥＦ
 （Ｖ）
(V
+
=6V,OSC:TriangleWaveform
V
P-P
=0.5V,Offset=0.5V,fosc=100kHz,Ta=25
℃
0
0.2
0.4
0.6
0.8
1
0 102030405060
SinkCurrentＩ
ＳＩＮＫ
 (mA)
ＬOutputVoltage 
V
ＯＬ
 （Ｖ）
(V
+
=6V,OUTPin=0V,OSC:TriangleWavefor
m
V
P-P
=0.5V,Offset=0.5V,fosc=100kHz,Ta=25
0
1
2
3
4
5
6
7
8
024681012
SourceCurrentＩ
ＳＯＵＲＣＥ
 (mA）
HOutputVoltage V
OH
 （Ｖ）
■ TYPICAL CHARACTERISTICS
H Output Voltage(OUT Pin) vs. Source Current L Output Voltage(OUT Pin) vs. Sink Current
Reference Voltage vs. Operating Voltage Operating Current vs. Operating Voltage
NJM2378
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Ver.2012-02-20
(V
+
=6V,R
L
=∞,OSC:TriangleWaveform
V
P-P
=0.5V,Offset=0.5V,fosc=100kHz)
0
1
2
3
4
5
-50-250 255075100125
AmbientTemperature Ｔａ （℃）
AverageQuiescentCurrent
Ｉ
ＣＣＡＶ
 （ｍＡ）
(V+=6V,OSC:TriangleWaveform
VP-P=0.5V,Offset=0.5V,fosc=100kHz)
0
0.5
1
1.5
2
-50 -25 0 25 50 75 100 125
AmbientTemperature Ｔａ （℃）
QuiescentCurrent(LatchMode)
ＩＣＣＬＡ （ｍＡ）
(V
+
=6V,I
SINK
=20mA,OSC:TriangleWaveform
V
P-P
=0.5V,Offset=0.5V,fosc=100kHz)
0
0.05
0.1
0.15
0.2
0.25
0.3
-50 -25 0 25 50 75 100 125
AmbientTemperature Ｔａ （℃）
LOutputVoltage Ｖ
ＯＬ
 （Ｖ）
(V
+
=6V,R
L
=10kΩ,OSC:TriangleWaveform
V
P-P
=0.5V,Offset=0.5V,fosc=100kHz)
0
1
2
3
4
5
6
-50 -25 0 25 50 75 100 125
AmbientTemperature Ｔａ （℃）
HOutputVoltage Ｖ
ＯＨ
 （Ｖ）
(V
+
=6V,OSC:TriangleWaveform
V
P-P
=0.5V,Offset=0.5V,fosc=100kHz)
8
9
10
11
12
-50 -25 0 25 50 75 100 125
AmbientTemperature Ｔａ （℃）
OutputSourceCurrent
I
SOURCE
（mA）
(V
+
=6V,I
OR
=1mA)
2.4
2.45
2.5
2.55
2.6
-50 -25 0 25 50 75 100 125
AmbientTemperature Ｔａ （℃）
ReferenceVoltage Ｖ
ＲＥＦ
 （Ｖ）
■ TYPICAL CHARACTERISTICS
Reference Voltage vs. Temperature Output Source Current (OUT Pin) vs. Temperature
H Output Voltage (OUT Pin) vs. Temperature L Output Voltage (OUT Pin) vs. Temperature
Quiescent Current(Latch Mode) vs. Temperature Average Quiescent Current vs. Temperature
NJM2378
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8
-Ver.2012-02-20
[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.