NJM2340
HIGH PRECISION DC/DC CONVERTER CONTROL IC
■GENERAL
DESCRIPTION
The
NJM2340
is a high precision DC/DC converter control
IC with a current sense amplifier. It offers a low side current
sensing which offers a DC/DC converter application with a few
external parts and minimum error. The NJM2340 has a high
input voltage and is available in small surface mount packages,
an 8-lead DMP and MSOP (TVSP). Therefore it is well-suited
for various applications.
■PACKAGE
OUTLINE
NJM2340M
(DMP8)
NJM2340RB1
(MSOP8 (TVSP8))
■FEATURES
●PWM
switching control
●Operating
Voltage
(3.6 to 32V)
●Wide
Oscillator Range
(20kHz to 500 kHz)
●Duty
Cycle
(0% to 100%)
●Current
Sensing Amplifier
●High
Precision Reference Voltage
Voltage Detect: 1V±1.5%
Current Detect: 150mV±4%
●Bipolar
Technology
●Package
Outline
DMP8, MSOP8 (TVSP8)*
*MEET JEDEC MO-187-DA / THIN TYPE
■PIN
CONFIGURATION
1
2
3
4
8
7
6
5
NJM2340M
NJM2340RB1
Pin Function
1.IN1
2.IN2
3.F.B
4.GND
5.OUT
6.CT
7.V
REF
8.V
+
Ver 2.0
- 1 -
NJM2340
■BLOCK
DIAGRAM
V
+
8
V
REF
7
CT
6
OUT
5
V
REF
OSC
ERROR AMP
1V
PWM
CURRENT
SENSE AMP
0.15V
1
IN1
2
IN2
3
F.B
4
GND
■ABSOLUTE
MAXIMUM RATINGS
(Ta=25°C )
PARAMETER
SYMBOL
RATINGS
Maximum Supply Voltage
V
+
36
Output Sink Current
I
SINK
15
Power Dissipation
(DMP8)
300
P
D
(MSOP8(TVSP8))
Operating Temperature Range
Topr
-40 to +85
Storage Temperature Range
Tstg
-50 to +150
UNIT
V
mA
320
mW
°C
°C
■RECOMMENDED
OPERATING CONDITIONS
PARAMETER
Supply Voltage
Oscillation Frequency
Oscillator Timing Resistance
SYMBOL
V
+
fosc
R
T
(Ta=25°C)
MIN.
3.6
20
20
MAX.
32
500
100
UNIT
V
kHz
kΩ
-2-
NJM2340
■ELECTRICAL
CHARACTERISTICS
(V
+
=12V,Ta=25°C)
REFERENCE VOLTAGE BLOCK
PARAMETER
SYMBOL
TEST CONDITION
Output Voltage
Line Regulation
Load Regulation
OSCILLATOR BLOCK
PARAMETER
Oscillation Frequency
V
REF
L
INE
L
OAD
I
OR
=1mA
V
+
=3.6
∼
32V, I
OR
=1mA
I
OR
=0.1
∼
5.0mA
MIN.
1.98
–
–
TYP.
2.00
4.0
6.0
MAX.
2.02
20
40
UNIT
V
mV
mV
SYMBOL
f
OSC
TEST CONDITION
R
T
=27kΩ, C
T
=220pF
MIN.
315
TYP.
350
MAX.
385
UNIT
kHz
CURRENT SENSE AMPLIFIER BLOCK
PARAMETER
SYMBOL
Reference Voltage1
Input Bias Voltage1
Maximum Output Voltage1
(F.B Pin)
Maximum Source Current1
(F.B Pin)
ERROR AMPLIFIER BLOCK
PARAMETER
Reference Voltage2
Input Bias Voltage2
Maximum Output Voltage2
(F.B Pin)
Maximum Source Current2
(F.B Pin)
PWM COMPARATE BLOCK
PARAMETER
Input Threshold Voltage (F.B Pin)
Input Threshold Voltage (F.B Pin)
OUTPUT BLOCK
PARAMETER
L Output Voltage (OUT Pin)
GENERAL CHARACTERISTICS
PARAMETER
Average Quiescent Current
V
B
1
I
B
1
V
OM+
1
V
OM-
1
I
OM
1
TEST CONDITION
MIN.
144
–
–
0.6
40
TYP.
150
20
V
REF
-0.15
0.75
85
MAX.
156
100
–
0.9
200
UNIT
mV
nA
V
V
µA
R
NF
=100kΩ
R
NF
=100kΩ
V
OM
1=0.5V
SYMBOL
V
B
2
I
B
2
V
OM+
2
V
OM-
2
I
OM
2
TEST CONDITION
MIN.
0.985
–
–
0.6
40
TYP.
1.000
20
V
REF
-0.15
0.75
85
MAX.
1.015
100
–
0.9
200
UNIT
V
nA
V
V
µA
R
NF
=100kΩ
R
NF
=100kΩ
V
OM
2=0.5V
SYMBOL
V
TH0
V
TH100
TEST CONDITION
duty·cycle=0%
(note)
duty·cycle=100%
(note)
MIN.
V
OM
-
–
TYP.
1.0
1.4
MAX.
1.1
–
UNIT
V
V
SYMBOL
V
OL
TEST CONDITION
I
SINK
=10mA
MIN.
–
TYP.
0.5
MAX.
0.7
UNIT
V
SYMBOL
I
CCAV
TEST CONDITION
R
L
=∞, duty·cycle=50%
MIN.
–
TYP.
1.5
MAX.
2.0
UNIT
mA
(note) Duty·Cycle is defined as follows:
Duty·Cycle=0%: IC output transistor is OFF.
Duty·Cycle=100%: IC output transistor is ON.
-3-
NJM2340
■TYPICAL
APPLICATION
V
IN
L
V
OUT
Q1
R
T
27k
Ω
C
T
220pF
R
BE
V
+
V
REF
CT
OUT
R
BC
5
8
7
6
V
REF
OSC
ERROR AMP
1V
R2
PWM
CURRENT
SENSE AMP
C
IN
D1
C
OUT
0.15V
1
2
3
4
IN1
IN2
C
NF
2
F.B
R
NF
2
R
NF
1
GND
R1
GND
IN
C
NF
1
R
SC
R
CIN
GND
OUT
-4-
NJM2340
■TIPICAL
CHARACTERISTICS
Oscillator Frequency vs. Timing Resistor
+
(V =12V,Ta=25°C)
C
T
=100pF
C
T
=220pF
Oscillator Frequency vs. Timing Capacitor
+
(V =12V,Ta=25°C)
1000
1000
Oscillator Frequency
f
OSC
(kHz)
Osillator Frequency
f
OSC
(kHz)
R
T
=47kΩ
100
100
C
T
=1000pF
R
T
=20kΩ
C
T
=4700pF
10
10
Timing Resistor R
T
(kΩ)
Reference Voltage vs. Output Current
+
(V =12V,Ta=25°C)
R
T
=100kΩ
10
100
10
100
1000
Timing Capacitor C
T
(pF)
10000
Reference Voltage V
REF
(V)
2.5
2
1.5
1
0.5
0
0
0.8
L Output Voltage V
OL
(V)
0.6
0.4
0.2
0
L Output Voltage vs. Source Current
+
(V =12V,Ta=25°C)
5
10
15
20
25
30
0
3
6
9
12
15
Output Current I
OR
(mA)
Source Current I
SOURCE
(mA)
Average Quiescent Current
I
CC
(mA)
3
2.5
2
1.5
1
0.5
0
0
Average Quiescent Current
(R
L
=
∞
,duty·cycle=50%,Ta=25°C)
10
20
電源電圧
V (V)
+
30
40
-5-
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