NJRC NJM2381

NJM2381
SWITCHING REGULATOR CONTROL IC FOR FLYBACK
WITH CURRENT SENSE AMPLIFIER
■GENERAL DESCRIPTION
■PACKAGE OUTLINE
The NJM2381 is a low voltage operation DC/DC converter
control IC.
It features totem pole output directly driving external
bipolar transistor and operates at high switching frequency
which improves transient response.
It is suitable for LCD back light, and other portable
applications.
■FEATURES
● PWM switching control
● Operating Voltage
(3.6 to 32V)
● Wide Oscillator Range
(5 to 350 kHz)
● Current Sensing Amplifier
● Soft-Start Function
● UVLO(Under Voltage Lockouts)
● Bipolar Technology
● Package Outline
DIP14, DMP14, SSOP10
NJM2381D
NJM2381M
NJM2381V
■PIN CONFIGURATION
1
14
2
13
3
12
4
11
5
10
6
9
7
8
PIN FUNCTION
8.NC
1.NC
9. V+
2.IN 1
3.IN 2
10.CS
11.CT
4.F.B
12.REF
5.GND
13.IN+
6.OUT
7.NC
14.NC
NJM2381D
NJM2381M
1
10
2
9
3
8
4
7
5
6
NJM2381V
PIN FUNCTION
6. V+
1.IN-1
2.IN-2
7.CS
8.CT
3.F.B
9.REF
4.GND
10.IN+
5.OUT
Ver 3.2 - 1 -
NJM2381
■BLOCK DIAGRAM
NC
IN+
REF
CT
CS
V+
NC
14
13
12
11
10
9
8
VREF
CURRENT
SENSE AMP
OSC
L.O
U.V.LO
500Ω
ER·AMP
PWM
0.52V
1
2
3
4
NC
IN-1
IN-2
F.B
5
GND
6
7
OUT
NC
(Package: DIP14, DMP14)
IN+
REF
10
9
CT
CS
V+
8
7
6
VREF
CURRENT
SENSE AMP
OSC
L.O
U.V.LO
500Ω
ER·AMP
PWM
0.52V
1
-
IN 1
2
3
-
F.B
IN 2
4
GND
5
OUT
(Package: SSOP10)
-2-
NJM2381
■ABSOLUTE MAXIMUM RATINGS (Ta=25°C )
PARAMETER
SYMBOL
Input Voltage
V+
Reference Output Current
IOR
Output Current
IO
Differential Input Voltage
VID
Common Mode Input Voltage
VIC
Power Dissipation
PD
Operating Temperature Range
Storage Temperature Range
MAXIMUM RATINGS
36
10
±50
2.5
-0.3 ∼ 2.5
(DIP 14)
700
(DMP 14) 300
(SSOP 10) 250
-40 ∼ +85
-50 ∼ +125
TOPR
TSTG
UNIT
V
mA
mA
V
V
mW
°C
°C
■ELECTRICAL CHARACTERISTICS (V+=6V,RT=33kΩ,CT=1000pF,Ta=25°C)
REFERENCE VOLTAGE BLOCK
PARAMETER
SYMBOL
Output Voltage
Line Regulation
Load Regulation
OSCILLATOR BLOCK
PARAMETER
Oscillation Frequency
Oscillate Fluctuations1
(Line Fluctuations)
Oscillate Fluctuations2
(Temp Fluctuations)
VREF
LINE
LOAD
IOR=1mA
+
V =3.6 ∼ 32V, IOR=1mA
IOR=0.1 ∼ 5.0mA
SYMBOL
TEST CONDITION
RT=33kΩ, CT=1000pF
MIN.
TYP.
MAX.
UNIT
2.45
–
–
2.50
6.8
5
2.55
20.7
30
V
mV
mV
MIN.
TYP.
MAX.
UNIT
105
1
125
–
kHz
%
fOSC
fdV
V =3.6 ∼ 32V
85
–
fdT
Ta=-40 ∼ 85°C
–
5
–
%
MIN.
TYP.
MAX.
UNIT
–
–
–
–
–
–
7
50
100
–
–
–
mV
nA
nA
dB
MHz
V
1
V
200
µA
CURRENT SENSE AMPLIFIER BLOCK
PARAMETER
SYMBOL
Input Offset Voltage1
Input Offset Current1
Input Bias Current1
Open Loop Gain1
Gain Bandwidth Product1
Input Common Mode
Voltage Ratio1
Maximum Output Voltage1
(F.B Pin)
Maximum Source Current1
(F.B Pin)
TEST CONDITION
+
TEST CONDITION
VIO1
IIO1
IB1
A V1
GB1
VICM1
VOM-1
RNF=100kΩ
–
2
5
5
90
0.6
0∼
VREF-0.8
–
IOM+1
VOM=0.5V
40
85
-3-
NJM2381
■ELECTRICAL CHARACTERISTICS (V+=6V,RT=33kΩ,CT=1000pF,Ta=25°C)
ERROR AMPLIFIER BLOCK
PARAMETER
SYMBOL
TEST CONDITION
MIN.
Reference Voltage2
Input Bias Voltage2
Open Loop Gain2
Gain Bandwidth Product2
Maximum Output Voltage2
(F.B Pin)
Maximum Source Current2
(F.B Pin)
PWM COMPARATE BLOCK
PARAMETER
VB2
IB2
A V2
GB2
VOM-2
RNF=100kΩ
IOM+2
VOM=0.5V
SYMBOL
Input Threshold Voltage
(F.B Pin)
Input Threshold Voltage
(F.B Pin)
Maximum Duty Cycle
TEST CONDITION
H-Output Voltage (OUT Pin)
L-Output Voltage (OUT Pin)
Output Source Current
(OUT Pin)
-4-
0.52
5
90
0.6
–
0.53
100
–
–
1
V
nA
dB
MHz
V
40
85
200
µA
MIN.
TYP.
MAX.
UNIT
1.65
1.75
V
VTH50
duty·cycle=50%
–
1.88
–
V
Current Sense Amp.=HIGH
Error Amp.=HIGH ,CS Pin=1.2V
55
64
85
%
MIN.
TYP.
MAX.
UNIT
TEST CONDITION
IBCS
VTHCS0
CS Pin=1.8V
duty·cycle=0%
–
–
250
0.25
650
0.35
nA
V
VTHCS50
duty·cycle=50%
–
0.52
–
V
MIN.
TYP.
MAX.
UNIT
–
–
60
2.70
2.52
180
–
–
–
V
V
mV
MIN.
TYP.
MAX.
UNIT
3.50
–
8
4.00
0.25
11
–
0.65
–
V
V
mA
MIN.
TYP.
MAX.
UNIT
1.2
1.5
1.8
V
–
–
1.6
3.5
2.2
4.8
mA
mA
TEST CONDITION
VTHON
VTHOFF
VHYS
SYMBOL
VOH
VOL
ISOURCE
GENERAL CHARACTERISTICS
PARAMETER
SYMBOL
Latch Mode
Threshold Voltage (CS Pin)
Quiescent Current
Average Quiescent Current
0.51
–
–
–
–
–
UNDER VOLTAGE LOCKOUT BLOCK
PARAMETER
SYMBOL
OUTPUT BLOCK
PARAMETER
UNIT
duty·cycle=0%
SOFT START CIRCUIT BLOCK
PARAMETER
SYMBOL
ON Threshold Voltage
OFF Threshold Voltage
Hysteresis Voltage
MAX.
VTH0
αM
Input Bias Current (CS Pin)
Input Threshold Voltage
(CS Pin)
Input Threshold Voltage
(CS Pin)
TYP.
TEST CONDITION
RL=10kΩ
Output Sink Current=20mA
OUT Pin=0V
TEST CONDITION
VTHLA
ICCLA
ICCAV
Latch Mode
RL=
, duty·cycle=50%
NJM2381
■ TYPICAL APPLICATIONS
330kΩ
4.7µF
330kΩ
V
+
1000pF
36kΩ
2.50V
10
9
8
VREF
CURRENT
SENSE AMP
7
6
VOUT
OSC
L.O
U.V.LO
500Ω
0.52V
1
ER·AMP
PWM
2
3
GND
4
5
(Package:SSOP10)
-5-
NJM2381
■TIPICAL CHARACTERISTICS
H Output Voltage vs. Source Current
(V+=6V,RT=33kΩ,CT=1000pF,
OUT Pin=0V,Ta=25°C)
1
L Output Voltage VOL (V)
H Output Voltage VOH (V)
8
7
6
5
4
3
2
1
0.8
0.6
0.4
0.2
0
0
Oscilltor Frequency f OSC
(kHz)
1000
2
4
6
8
10
20
30
40
50
60
Sink Current ISINK (mA)
Oscillator Frequency vs. Timing Resistor
(V+=6V,Ta=25°C)
Oscillator Frequency vs. Timing Capacitor
(V+=6V,Ta=25°C)
1000
CT=470pF
100
CT=1000pF
RT=10kΩ
RT=33kΩ
10
1
RT=100kΩ
1
1
10
100
1000
Timing Resistor RT (kΩ)
10000
10
Reference Voltage vs. Operating Voltage
(V+=6V,Ta=25°C)
2.52
2.51
2.5
2.49
2.48
100
1000
10000
Timing Capacitor CT (pF)
100000
Operating Current vs. Operating Voltage
(Ta=25°C)
6
Operating Voltage ICC (mA)
Reference Voltage VREF (V)
10
Source Current ISOURCE (mA)
100
10
0
12
Oscillator Frequencey fOSC
(kHz)
0
5
4
ICCAV
3
2
ICCLA
1
0
0
10
20
30
+
Operating Voltage V (V)
-6-
L Output Voltage vs. Sink Current
(V+=6V,RT=33kΩ,CT=1000pF,Ta=25°C)
40
0
10
20
30
+
Operating Voltage V (V)
40
NJM2381
Maximum Duty Cycle vs. Oscillator Frequency
(V+=6V,Ta=25°C)
80
70
60
50
40
30
20
10
0
10
Duty Cycle α (%)
Maximum Duty Cycle αM (%)
■TIPICAL CHARACTERISTICS
100
Oscillator Frequency f OSC (kHz)
1000
Duty Cycle vs. CS Pin Voltage
(V+=6V,Ta=25°C)
80
70
60
50
40
30
20
10
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
CS Pin Voltage VTHCS (V)
-7-
NJM2381
■TIPICAL CHARACTERISTICS
3
140
Reference Voltage
VREF (V)
Oscillator Frequency
f OSC (kHz)
160
Oscillator Frequency vs. Temperature
(V+=6V,RT=33kΩ,CT=1000pF)
120
100
80
2.8
2.6
2.4
2.2
2
60
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (°C)
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (°C)
H Output Voltage vs. Temperature
(V =6V,RL=10kΩ,RT=33kΩ,CT=1000pF)
L Output Voltage vs. Trmperature
(V =6V,ISINK=20mA,RT=33kΩ,CT=1000pF)
+
+
0.5
L Output Voltage V OL (V)
H Output Voltage VOH (V)
10
Reference Voltage vs. Temperature
(V+=6V,IOR=1mA)
8
6
4
2
0.4
0.3
0.2
0.1
0
0
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (°C)
Operating Current ICC (mA)
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (°C)
5
Operating Current vs. Temperature
(V+=6V,RT=33kΩ,CT=1000pF)
4
3
ICCAV
2
ICCLA
1
0
-50 -25
0
25
50
75 100 125 150
Ambient Temperature Ta (°C)
-8-
[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.