NJM2368
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1
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Ver.2011-12-22
NJM2368D NJM2368M
( DIP8 ) ( DMP8 )
NJM2368E NJM2368V
( SOP8 ) ( SSOP8 )
SWITCHING REGULATOR CONTROL IC FOR FLYBACK
■GENERAL DESCRIPTION ■PACKAGE OUTLINE
■FEATURES
● Operating Voltage (3.6V ~ 32V)
● Wide Oscillator Range (5kHz ~ 350 kHz)
● Soft-Start function.
● Under Voltage Lockouts (U.V.L.O.)
● Bipolar Technology
● Package Outline DIP8, DMP8, SOP8 JEDEC 150mil,
SSOP8
■BLOCK DIAGRAM
1
VREF
V+
ER⋅AMP
L.O
500Ω
U.V.LO
OSC
PW M
8 7 6 5
432
CSCTREF
IN- OUTGNDF. B
0.52V
S.C.P
30uA
The NJM2368 is a high speed switching regulator control I
C
which can operate at low voltage.
It uses a totempole output circuit , so that it can drive an
external Bipolar Transistor directly.
It is suitable for applications of flyback type switching
regulation of up to 10W.
1. IN-
2. F.B
3. GND
4. OUT
5. V+
6. CS
7. CT
8. REF
PIN FUNCTION
NJM2368
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2
-Ver.2011-12-22
■ABSOLUTE MAXIMUM RATINGS (Ta=25°C)
PARAMETER SYMBOL MAXIMUM RATINGS UNIT
Input Voltage V+ 36 V
Reference Output Current IOR 10 mA
Output Current IO ±50 mA
Power Dissipation PD
(DIP 8) 700
(DMP 8) 300
(SOP 8) 300
(SSOP 8) 250
mW
Operating Temperature Range TOPR -40 ~ +85 °C
Storage Temperature Range TSTG -50 ~ 125 °C
■RECOMMENDED OPERATING CONDITIONS (V+=6V, Ta=25°C)
PARAMETER SYMBOL RATINGS MIN. MAX. UNIT
Operating Voltage V+ 3.6 32 V
Feed Back Resistor RNF 100 – kΩ
Oscillator Timing Capacitor CT 220 22,000 pF
Oscillator Timing Resistor RT 22 100 kΩ
Oscillate fOSC 5 350 kHz
■ELECTRICAL CHARACTERISTICS (V+=6V, RT=33kΩ, CT=1,000pF, Ta=25°C)
REFERENCE VOLTAGE BLOCK
PARAMETER SYMBOL RATINGS MIN. TYP. MAX. UNIT
Output Voltage VREF I
OR=1mA 2.45 2.50 2.55 V
Line Regulation LINE V
+=3.6V ~ 32V, IOR=1mA – 6.8 20.7 mV
Load Regulation LOAD IOR=0.1mA ~ 5.0mA – 5 30 mV
OSCILLATOR BLOCK
PARAMETER SYMBOL RATINGS MIN. TYP. MAX. UNIT
Oscillate fosc CT=1,000pF, RT=33kΩ 85 105 125 kHz
Oscillate Fluctuations1
(Line Fluctuations)
fdv V+=3.6V ~ 32V – 1 – %
Oscillate Fluctuations2
(Temp Fluctuations)
fdt Ta =-40 °C ~ +85°C – 5 – %
ERROR AMPLIFIER BLOCK
PARAMETER SYMBOL RATINGS 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
VOM+ R
NF=100kΩ V
REF-0.2 – – V
Maximum Output Voltage
(F.B Pin) VOM- R
NF=100kΩ – – 200 mV
Output Source Current
(F.B Pin) IOM+ V
OM=1V 40 85 200 uA
NJM2368
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3
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Ver.2011-12-22
■ELECTRICAL CHARACTERISTICS (V+=6V, RT=33kΩ, CT=1,000pF, Ta=25°C)
PWM COMPARATE BLOCK
PARAMETER SYMBOL RATINGS MIN. TYP. MAX. UNIT
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 RATINGS 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
SHORT CIRCUIT PROTECTION
PARAMETER SYMBOL RATINGS 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 uA
Latch mode Threshold Voltage
(CS Pin) VTHLA 1.20 1.50 1.80 V
UNDER VOLTAGE LOCKOUT
PARAMETER SYMBOL RATINGS 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 RATINGS 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 CHARACTERISTIC
PARAMETER SYMBOL RATINGS MIN. TYP. MAX. UNIT
Quiescent Current ICCLA Latch Mode – 1.6 2.2 mA
Average Quiescent Current ICCAV R
L=∞, duty·cycle=50% – 3.5 4.8 mA
NJM2368
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4
-Ver.2011-12-22
■ TYPICAL APPLICATIONS
RT
36kΩ
GND
V+
VOUT
+5V
Rsf
330kΩ
Rsr
180kΩ
Cs
4.7uF
CT
1,000pF
1
VREF
ER⋅AMP
L.O
500Ω
U.V.LO
OSC
PWM
8 7 6 5
43 2
0.52V
S.C.P
30uA
GND
CIN
Q1
RNF
1MΩ
CLP
2,200pF
R2
22kΩ
D1
R1
2.2kΩ
COUT
N1 N2
2kΩ
*100kΩ
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.
NJM2368
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5
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Ver.2011-12-22
■TYPICAL CHARACTERISTICS
0
1
2
3
4
5
6
7
8
024681012
H Output Voltage vs. Source Current
(V+=6V, RT=33kΩ, CT=1,000pF, Ta=25oC)
Source Current I
SOURCE (mA)
H Output Voltage VOH (V)
0
0.2
0.4
0.6
0.8
1
0 102030405060
L Output Voltage vs. Sink Current
(V+=6V, RT=33kΩ, CT=1,000pF, Ta=25
oC)
Sink Current I
SINK (mA)
L Output Voltage VOL (V)
1
10
100
1000
10 100
Oscillator Frequency vs. Timing Resistor
(V+=6V, Ta=25oC)
Timing Resistor R
T (kΩ)
Oscillator Frequency fOSC (kHz)
CT=1,000pF
CT=470pF
1
10
100
1000
10 100 1000 10000 100000
RT=33kΩ
Oscillator Frequency fOSC (kHz)
Oscillator Frequency vs. Timing Capacitor
(V+=6V, Ta=25oC)
Timing Capacitor CT (pF)
RT=100kΩ
2.48
2.49
2.5
2.51
2.52
0 10203040
Reference Voltage vs. Operating Voltage
(Ta=25oC)
Operating Voltage V+ (V)
Reference Voltage VREF (V)
0
1
2
3
4
5
6
0 10203040
Operating Current vs. Operating Voltage
(Ta=25oC)
Operating Voltage V
+ (V)
Operating Current ICC (mA)
ICCAV
ICCLA
NJM2368
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-Ver.2011-12-22
■TYPICAL CHARACTERISTICS
60
80
100
120
140
160
-50 -25 0 25 50 75 100 125
Ambient Temperature Ta (
oC)
Oscillator Frequency fOSC (kHz)
Oscillator Frequency vs. Temperature
(V+=6V, RT=33kΩ, CT=1,000pF)
2
2.2
2.4
2.6
2.8
3
-50 -25 0 25 50 75 100 125
Ambient Temperature Ta (
oC)
Referece Voltage VREF (V)
Referece Voltage vs. Temperature
(V+=6V, I
OR=1mA)
0
2
4
6
8
10
-50 -25 0 25 50 75 100 125
Ambient Temperature Ta (
oC)
H Output Voltage VOH (V)
H Output Voltage vs. Temperature
(V+=6V, RL=10kΩ, RT=33kΩ, CT=1,000pF)
0
0.1
0.2
0.3
0.4
0.5
-50 -25 0 25 50 75 100 125
Ambient Temperature Ta (
oC)
L Output Voltage VOL (V)
L Output Voltage vs. Temperature
(V+=6V, ISINK=20mA, RT=33kΩ, CT=1,000pF)
1
1.2
1.4
1.6
1.8
2
-50 -25 0 25 50 75 100 125
Ambient Temperature Ta (
oC)
Quiescent Current
ICCLA (mA)
Quiescent Current vs. Temperature
(Latch Mode, V+=6V, RT=33kΩ, CT=1,000pF)
0
1
2
3
4
5
-50 -25 0 25 50 75 100 125
Ambient Temperature Ta (
oC)
Average Quiescent Current
ICCAV (mA)
Average Quiescent Current vs. Temperature
(V+=6V, RL=∞, duty cycle=50%, R
T=33kΩ, CT=1,000pF)
NJM2368
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7
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Ver.2011-12-22
■TYPICAL CHARACTERISTICS
0
10
20
30
40
50
60
70
80
10 100 1000
Maximum Duty Cycle vs. Oscillator Frequency
(V+=6V, Ta=25oC)
Oscillator Frequency f
OSC (kHz)
Maximum Duty Cycle αM (%)
0
10
20
30
40
50
60
70
80
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Duty Cycle vs. CS Pin Voltage
(V+=6V, Ta=25oC)
CS Pin Voltage V
THCS (V)
Duty Cycle α (%)
[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.
