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Электронный компонент: NJM2381V

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NJM2381
Ver 3.2
- 1 -
SWITCHING REGULATOR CONTROL IC FOR FLYBACK
WITH CURRENT SENSE AMPLIFIER
s
GENERAL DESCRIPTION
sPACKAGE OUTLINE










s
FEATURES
q
PWM switching control
q
Operating Voltage
(3.6 to 32V)
q
Wide Oscillator Range
(5 to 350 kHz)
q
Current Sensing Amplifier
q
Soft-Start Function
q
UVLO(Under Voltage Lockouts)
q
Bipolar Technology
q
Package Outline DIP14, DMP14, SSOP10


s
PIN CONFIGURATION
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.
NJM2381D
NJM2381V
NJM2381M
1.IN
-
1
2.IN
-
2
3.F.B
4.GND
5.OUT
6. V
+
7.CS
8.CT
9.REF
10.IN
+
PIN FUNCTION
1
4
3
2
5
6
7
8
9
10
NJM2381D
NJM2381M
1.NC
2.IN
-
1
3.IN
-
2
4.F.B
5.GND
6.OUT
7.NC
8.NC
9. V
+
10.CS
11.CT
12.REF
13.IN
+
14.NC
PIN FUNCTION
1
4
3
2
14
11
12
13
5
6
7
8
9
10
NJM2381V
NJM2381
- 2 -

s
BLOCK DIAGRAM

1
V
REF
CURRENT
SENSE AMP
V
+
ERAMP
L.O
500
U.V.LO
OSC
PWM
9 8
7
6
5
4
3
2
10
CS
CT
IN
+
REF
IN
-
1 IN
-
2 OUT
GND
F.B
0.52V
11
12
13
14
NC
NC
NC
NC
(Package: DIP14, DMP14)


1
V
REF
CURRENT
SENSE AMP
V
+
ERAMP
L.O
500
U.V.LO
OSC
PWM
9 8
7
6
5
4
3
2
10
CS
CT
IN
+
REF
IN
-
1 IN
-
2 OUT
GND
F.B
0.52V
(Package: SSOP10)
NJM2381
- 3 -

s
ABSOLUTE MAXIMUM RATINGS (Ta=25C
)
PARAMETER SYMBOL
MAXIMUM
RATINGS
UNIT
Input Voltage
V
+
36 V
Reference Output Current
I
OR
10
mA
Output Current
I
O
50
mA
Differential Input Voltage
V
ID
2.5 V
Common Mode Input Voltage
V
IC
-0.3
2.5
V
Power Dissipation
P
D
(DIP 14) 700
(DMP 14) 300
(SSOP 10) 250
mW
Operating Temperature Range
T
OPR
-40
+85
C
Storage Temperature Range
T
STG
-50
+125
C


s
ELECTRICAL CHARACTERISTICS (V
+
=6V,R
T
=33k,C
T
=1000pF,Ta=25C)

REFERENCE VOLTAGE BLOCK
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Output Voltage
V
REF
I
OR
=1mA 2.45
2.50
2.55
V
Line Regulation
L
INE
V
+
=3.6
32V, I
OR
=1mA
6.8
20.7
mV
Load Regulation
L
OAD
I
OR
=0.1
5.0mA
5 30
mV

OSCILLATOR BLOCK
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Oscillation Frequency
f
OSC
R
T
=33k, C
T
=1000pF 85
105
125
kHz
Oscillate Fluctuations1
(Line Fluctuations)
f
dV
V
+
=3.6
32V
1 %
Oscillate Fluctuations2
(Temp Fluctuations)
f
dT
Ta=-40
85C
5 %

CURRENT SENSE AMPLIFIER BLOCK
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Input Offset Voltage1
V
IO
1
2
7 mV
Input Offset Current1
I
IO
1
5
50 nA
Input Bias Current1
I
B
1
5 100 nA
Open Loop Gain1
A
V
1
90
dB
Gain Bandwidth Product1
G
B
1
0.6
MHz
Input Common Mode
Voltage Ratio1
V
ICM
1
0
V
REF
-0.8
V
Maximum Output Voltage1
(F.B Pin)
V
OM-
1 R
NF
=100k
1
V
Maximum Source Current1
(F.B Pin)
I
OM+
1 V
OM
=0.5V 40
85
200
A
NJM2381
- 4 -
s
ELECTRICAL CHARACTERISTICS (V
+
=6V,R
T
=33k,C
T
=1000pF,Ta=25C)
ERROR AMPLIFIER BLOCK
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Reference Voltage2
V
B
2
0.51 0.52 0.53 V
Input Bias Voltage2
I
B
2
5 100 nA
Open Loop Gain2
A
V
2
90
dB
Gain Bandwidth Product2
G
B
2
0.6
MHz
Maximum Output Voltage2
(F.B Pin)
V
OM-
2 R
NF
=100k
1
V
Maximum Source Current2
(F.B Pin)
I
OM+
2 V
OM
=0.5V 40
85
200
A

PWM COMPARATE BLOCK
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Input Threshold Voltage
(F.B Pin)
V
TH0
dutycycle=0%
1.65 1.75 V
Input Threshold Voltage
(F.B Pin)
V
TH50
dutycycle=50%
1.88
V
Maximum Duty Cycle
M Current
Sense
Amp.=HIGH
Error Amp.=HIGH ,CS Pin=1.2V
55 64 85 %

SOFT START CIRCUIT BLOCK
PARAMETER SYMBOL
TEST
CONDITION
MIN.
TYP.
MAX.
UNIT
Input Bias Current (CS Pin)
I
BCS
CS
Pin=1.8V
250 650 nA
Input Threshold Voltage
(CS Pin)
V
THCS0
dutycycle=0%
0.25 0.35
V
Input Threshold Voltage
(CS Pin)
V
THCS50
dutycycle=50%
0.52
V

UNDER VOLTAGE LOCKOUT BLOCK
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
ON Threshold Voltage
V
THON
2.70
V
OFF Threshold Voltage
V
THOFF
2.52
V
Hysteresis Voltage
V
HYS
60 180
mV

OUTPUT BLOCK
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
H-Output Voltage (OUT Pin)
V
OH
R
L
=10k 3.50
4.00
V
L-Output Voltage (OUT Pin)
V
OL
Output Sink Current=20mA
0.25
0.65
V
Output Source Current
(OUT Pin)
I
SOURCE
OUT
Pin=0V
8
11
mA

GENERAL CHARACTERISTICS
PARAMETER SYMBOL TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Latch Mode
Threshold Voltage (CS Pin)
V
THLA
1.2 1.5 1.8 V
Quiescent Current
I
CCLA
Latch
Mode
1.6 2.2 mA
Average Quiescent Current
I
CCAV
RL= , dutycycle=50%
3.5
4.8
mA
NJM2381
- 5 -

s
TYPICAL APPLICATIONS
1
V
REF
CURRENT
SENSE AMP
ERAMP
L.O
500
U.V.LO
OSC
PWM
9 8 7 6
5
4
3
2
10
0.52V
36k
GND
2.50V
V
+
V
OUT
330k 330k
4.7F
1000pF
(Package:SSOP10)