NJU7650
Step-Down switching regulator IC with Constant Current Control
■
GENERAL DESCRIPTION
The
NJU7650
is a low voltage operation high-speed switching
regulator control IC for step-down converter, with a constant current
control. It incorporates a totem pole output, which can drive an
external MOS-FET easily. It also incorporates error amplifier and
current sense amplifier, which can allow the constant
voltage/current control for output voltage. Therefore the NJU7650 is
suitable for a LED driving, battery charger and other CCCV
applications. The NJU7650 is available in a small and thin 8-lead
MSOP (TVSP) package.
■
FEATURES
●
PWM switching control
●
Constant Current Control
●
Operating Voltage
2.2V to 8V
●
Wide Oscillator Range 300kHz to 1MHz
●
Maximum Duty Cycle
100%
●
Quiescent Current
800µA typ.
●
Soft-Start Function
Internal : 16ms typ. or adjustable
●
Dead Time Control
●
C-MOS Technology
●
Package Outline
NJU7650RB1 : MSOP8 (TVSP8)*
*MEET JEDEC MO-187-DA / THIN TYPE
■
PACKAGE OUTLINE
NJU7650RB1
(MSOP8 (TVSP8))
■
PRODUCT VARIATION
NJU7650
Constant Current Control
NJU7640
Over Current Protection
NJU7630
PWM Control
■
PIN CONFIGURATION
1
2
3
4
8
7
6
5
NJU7650RB1
PIN FUNCTION
1. OUT
2. V
+
3. FB
4. IN-1
5. IN-2
6. DTC
7. RT
8. GND
Ver.2012-08-03
-1-
NJU7650
■
BLOCK DIAGRAM
V
+
FB
Error AMP
0.8V
IN-1
−1
1V
Soft Start
0.2V
IN-2
−1
UVLO
0.2V
Current
Sense AMP
PWM
Buffer
OSC
0.5V
0.5
R
T
A
OUT
DTC
RT
R
T
GND
-2-
Ver.2012-08-03
NJU7650
■
ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
Supply Voltage
V
+
Output Pin Current
I
O
Power Dissipation
P
D
Operating Temperature Range
T
OPR
Storage Temperature Range
T
STG
(Ta=25°C)
UNIT
V
mA
mW
°C
°C
MAXIMUM RATINGS
+9
±50
MSOP8 (TVSP8) :320
-40 to +85
-40 to +125
■
RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
MIN.
+
Operating Voltage
V
2.2
Oscillator Timing Resistor
R
T
30
Oscillation Frequency
f
OSC
300
TYP.
–
47
700
MAX.
8
120
1,000
(Ta=25°C)
UNIT
V
kΩ
kHz
■
ELECTRICAL CHARACTERISTICS
PARAMETER
Under Voltage Lockout Block
ON Threshold Voltage
OFF Threshold Voltage
Hysteresis Voltage
Soft Start Block
Soft Start Time
Oscillator Block
RT Pin Voltage
Oscillation Frequency
Oscillate Supply Voltage
Fluctuations
Oscillate Temperature
Fluctuations
SYMBOL
TEST CONDITION
(V
+
=3.3V, R
T
=47kΩ, Ta=25°C)
MIN.
TYP.
MAX.
UNIT
V
T_ON
V
T_OFF
V
HYS
V
+
= L
→
H
V
+
= H
→
L
1.9
1.8
60
2.0
1.9
100
2.1
2.0
–
V
V
mV
T
SS
V
T_ON
→
Duty=80%
8
16
24
ms
V
RT
f
OSC
f
DV
f
DT
V
+
=2.2V to 8V
Ta=-40°C to +85°C
-5%
630
–
–
0.5
700
1
3
+5%
770
–
–
V
kHz
%
%
Ver.2012-08-03
-3-
NJU7650
■
ELECTRICAL CHARACTERISTICS
PARAMETER
Error Amplifier Block
Reference Voltage 1
Input Bias Current 1
Open Loop Gain 1
Gain Bandwidth Product 1
Output Source Current 1
Output Sink Current 1
Current Sense Amplifier Block
Reference Voltage 2
Input Bias Current 2
Open Loop Gain 2
Gain Bandwidth Product 2
Output Sink Current 2
PWM Comparate Block
Input Threshold Voltage
Maximum Duty Cycle
Output Block
Output High Level
ON Resistance
Output Low Level
ON Resistance
General Characteristics
Quiescent Current
V
T_0
V
T_50
M
AX
D
UTY_1
M
AX
D
UTY_2
Duty=0%
Duty=50%
V
FB
=0.9V
V
FB
=0.9V, R
DTC
=47kΩ
0.16
0.44
100
40
0.22
0.5
–
50
0.28
0.56
–
60
V
V
%
%
SYMBOL
TEST CONDITION
(V
+
=3.3V, R
T
=47kΩ, Ta=25°C)
MIN.
TYP.
MAX.
UNIT
V
B1
I
B1
A
V1
G
B1
I
OM+_1
I
OM+_2
I
OM1-
V
FB
=1V, V
IN-1
=0.9V, V
IN-2
=0.1V
V
FB
=1V, V
IN-1
=0.9V, V
IN-2
=0.1V,
V
+
=2.2V
V
FB
=1V, V
IN-1
=1.1V, V
IN-2
=0.1V
-1.0%
-0.1
–
–
25
4
0.10
1.00
–
80
1
55
9
0.16
+1.0%
0.1
–
–
95
16
0.22
V
µA
dB
MHz
mA
mA
mA
V
B2
I
B2
A
V2
G
B2
I
OM2-
V
FB
=1V, V
IN-1
=0.9V, V
IN-2
=0.3V
-10%
-0.1
–
–
0.10
0.2
–
70
1
0.16
+10%
0.1
–
–
0.22
V
µA
dB
MHz
mA
R
OH
R
OL
I
O
=-20mA
I
O
=+20mA
–
–
10
5
20
10
Ω
Ω
I
DD
R
L
=Non Load
–
800
1200
µA
-4-
Ver.2012-08-03
NJU7650
■
TYPICAL APPLICATIONS
Step-Down Converter
FET
V
IN
C
IN
SBD
C
OUT
R2
L
V
OUT
GND
OUT
NJU7650
1
R1
GND
RT
DTC
IN-2
R
CNF
8
R
SC
OUT
V
+
2
7
C
3
R
T
R
DTC
C
S
FB
IN-1
C
CNF
6
C
NF
R
NF
4
5
R
CIN
Ver.2012-08-03
-5-
