NJM2377
Ver 2.0
- 1 -
SWITCHING REGULATOR CONTROL IC
GENERAL DESCRIPTION
PACKAGE OUTLINE
FEATURES
PWM switching control
Operating Voltage
(2.7 to 18V)
Wide Oscillator Range
(10 to 500 kHz)
ON/OFF Maximum Duty Cycle (Ton:Toff = 9:1)
Totem Pole Output
Soft-Start Function
UVLO (Under Voltage Lockout)
Bipolar Technology
Package Outline DIP8, DMP8, SSOP8, VSP8
BLOCK DIAGRAM
The
NJM2377
is a high speed low voltage operation
switching regulator control IC.
It features a totem pole driver circuit that can directly drive
an external Bipolar transistor.
The
NJM2377
is suitable for potable applications, including
TFT panel supply with fly-back configuration.
NJM2377D
NJM2377V
NJM2377M
NJM2377R
1. IN
-
2. F.B
3. GND
4. OUT
5. V
+
6. CS
7. CT
8. REF
PIN FUNCTION
1
V
REF
ERAMP
L.O
U.V.LO
OSC
PWM
8 7 6 5
4
3
2
0.52V
S.C.P
30uA
IN
-
F.B GND
OUT
V
+
CS
CT
REF
NJM2377
- 2 -
ABSOLUTE MAXIMUM RATINGS (Ta=25C)
PARAMETER SYMBOL
MAXIMUM
RATINGS
UNIT
Input Voltage
V
+
18 V
Output Current
I
O
50
mA
Power Dissipation
P
D
(DIP 8)
700
(DMP 8)
300
(SSOP 8) 250
(VSP 8) 320
mW
Operating Temperature Range
T
OPR
-40
+85
C
Storage Temperature Range
T
STG
-50
+125
C
RECOMEND OPERATING CONDITIONS (V
+
=3V, Ta=25C)
PARAMETER SYMBOL
MIN.
MAX.
UNIT
Operating Voltage
V
+
2.7 18 V
Feed Back Resistor
R
NF
100
k
Oscillator Timing Capacitor
C
T
220
22,000 pF
Oscillator Timing Resistor
R
T
5 100 k
Oscillation Frequency
f
OSC
10 500 kHz
NJM2377
- 3 -
ELECTRICAL CHARACTERISTICS (V
+
=3V,R
T
=39k,C
T
=470pF,Ta=25C)
REFERENCE VOLTAGE BLOCK
PARAMETER SYMBOL
TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Output Voltage
V
REF
I
OR
=1mA 1.47
1.50
1.53
V
Line Regulation
V
O
-V
IN
V
+
=2.7
18V, I
OR
=1mA
3.8
11.5
mV
Load Regulation
V
O
-I
O
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
=39k, C
T
=470pF 80
100
120
kHz
Oscillate Fluctuations1
(Line Fluctuations)
f
dV
V
+
=2.7
18V
1 %
Oscillate Fluctuations2
(Temp Fluctuations)
f
dT
Ta=-40C
+85C
5 %
ERROR AMPLIFIER BLOCK
PARAMETER SYMBOL
TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Reference Voltage
V
B
0.51 0.52 0.53 V
Input Bias Voltage
I
B
5 100 nA
Open Loop Gain
A
V
90 dB
Gain Bandwidth Product
G
B
1.0 MHz
Maximum Output Voltage
(F.B Pin)
V
OM+
R
NF
=100k, IN
-
Pin=0V
1.9
2.2
2.4
V
V
OM-
R
NF
=100k, IN
-
Pin=0V
200
mV
Output Source Current
(F.B Pin)
I
OM+
V
OM
=1V, IN
-
Pin=0V
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%
0.45 0.65 V
Input Threshold Voltage
(F.B Pin)
V
TH80
dutycycle=80%
1.05
V
Maximum Duty Cycle
M F.B
Pin=1.2V
R
T
=39k, C
T
=470pF
80 90 %
SOFT START CIRCUIT BLOCK
PARAMETER SYMBOL
TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Input Bias Current
(CS Pin)
I
BCS
250 650 nA
Input Threshold Voltage
(CS Pin)
V
THCS0
dutycycle=0%, F.B Pin=1.2V
0.25
0.35
V
Input Threshold Voltage
(CS Pin)
V
THCS80
dutycycle=80%, F.B Pin=1.2V
0.79
V
NJM2377
- 4 -
ELECTRICAL CHARACTERISTICS (V
+
=3V,R
T
=39k,C
T
=470pF,Ta=25C)
SHORT CIRCUIT PROTECTION
PARAMETER SYMBOL
TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Input Threshold Voltage
(F.B Pin)
V
THPC
1.30 1.50 1.80 V
Charge Current (CS Pin)
I
CHG
CS Pin=0V, F.B Pin=2V
10
30
50
A
Latch Mode Threshold
Voltage (CS Pin)
V
THLA
1.20 1.50 1.80 V
UNDER VOLTAGE LOCKOUT
PARAMETER SYMBOL
TEST
CONDITION MIN.
TYP.
MAX.
UNIT
ON Threshold Voltage
V
THON
1.95
V
OFF Threshold Voltage
V
THOFF
1.78
V
Hysteresis Voltage
V
HYS
60 170
mV
OUTPUT BLOCK
PARAMETER SYMBOL
TEST
CONDITION MIN.
TYP.
MAX.
UNIT
H-Output Voltage (OUT Pin)
V
OH
R
L
=10k 1.7
2.0
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
23
35
mA
GENERAL CHARACTERISTICS
PARAMETER SYMBOL
TEST
CONDITION MIN.
TYP.
MAX.
UNIT
Quiescent Current
I
CCLA
Latch Mode, CS Pin=1.8V
1.7
2.4
mA
Average Quiescent Current
I
CCAV
R
L
= , dutycycle=50%
5.0
6.8
mA
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