NJRC NJU7631 Step-down switching regulator ic with power saving pwm/pfm control Datasheet

NJU7631
Step-Down Switching Regulator IC with Power Saving PWM/PFM control
■ GENERAL DESCRIPTION
■ PACKAGE OUTLINE
The NJU7631 is a low voltage operation high-speed switching
regulator control IC for step-down converter, with PWM/PFM
switching control. It can improve a switching efficiency on light load
with automatically changing between PWM and PFM controls. It
incorporates a totem pole output, which can drive an external
MOS-FET easily. The NJU7631 also has a soft-start function, dead
time control and timer latch for short circuit protection and their
times are all adjustable with external parts. It is available in a small
and thin 8-lead MSOP (TVSP) package.
■ FEATURES
● Automatic PWM/PFM 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
● Timer Latch for Short Circuit Protection
● C-MOS Technology
● Package Outline
NJU7631RB1 : MSOP8 (TVSP8)*
NJU7631RB1
(MSOP8 (TVSP8))
■ PRODUCT VARIATION
NJU763x**
Standby Function
PWM/PFM
NJU7631
PWM/PFM
Light Load to Efficiency
NJU7630
PWM Control
** Planning
*MEET JEDEC MO-187-DA / THIN TYPE
■ PIN CONFIGURATION
1
8
2
7
3
6
4
5
NJU7631RB1
Ver.2012-08-03
PIN FUNCTION
1. OUT
2. V+
3. FB
4. IN5. SCP
6. DTC
7. RT
8. GND
-1-
NJU7631
■ BLOCK DIAGRAM
+
V
FB
0.8V
ER⋅AMP
IN-
0.2V
1V
Vref
PWM/PFM
Control
Soft Start
UVLO
Latch
PWM
2µA
SCP
Buffer
OUT
SCP
OSC
2kΩ
0.5V
1V
0.5
A
RT
1V
DTC
RT
GND
RT
-2-
Ver.2012-08-03
NJU7631
■ ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
Supply Voltage
V+
Output Pin Current
IO
Power Dissipation
PD
Operating Temperature Range
TOPR
Storage Temperature Range
TSTG
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
RT
30
Oscillation Frequency
fOSC
300
TYP.
–
47
700
Under Voltage Lockout Block
ON Threshold Voltage
OFF Threshold Voltage
Hysteresis Voltage
Soft Start Block
Soft Start Time
Short Circuit Protection Block
Input Threshold Voltage
Charge Current
Latch Mode
ON Threshold Voltage
Latch Mode
OFF Threshold Voltage
Oscillator Block
RT Pin Voltage
Oscillation Frequency
Oscillate Supply Voltage
Fluctuations
Oscillate Temperature
Fluctuations
Ver.2012-08-03
MAX.
8
120
1,000
(Ta=25°C)
UNIT
V
kΩ
kHz
(V+=3.3V, RT=47kΩ, Ta=25°C)
■ ELECTRICAL CHARACTERISTICS
PARAMETER
(Ta=25°C)
UNIT
V
mA
mW
°C
°C
SYMBOL
VT_ON
VT_OFF
VHYS
TSS
TEST CONDITION
V+= L → H
V+= H → L
VT_ON → Duty=80%
MIN.
TYP.
MAX.
UNIT
1.9
1.8
60
2.0
1.9
100
2.1
2.0
–
V
V
mV
8
16
24
ms
VT_PC
ICHG
FB Pin
VSCP=0V
0.95
1.5
1.00
2
1.05
2.5
V
µA
VT_LA
SCP Pin
0.95
1.00
1.05
V
VT_LAOFF
SCP Pin
0.2
0.45
0.7
V
-5%
630
0.5
700
+5%
770
V
kHz
VRT
fOSC
fDV
V+=2.2V to 8V
–
1
–
%
fDT
Ta=-40°C to +85°C
–
3
–
%
-3-
NJU7631
(V+=3.3V, RT=47kΩ, Ta=25°C)
■ ELECTRICAL CHARACTERISTICS
PARAMETER
Error Amplifier Block
Reference Voltage
Input Bias Current
Open Loop Gain
Gain Bandwidth Product
Output Source Current
Output Sink Current
SYMBOL
TEST CONDITION
VB
IB
AV
GB
IOM+_1
IOM+_2
IOM-
VFB=1V, VIN-=0.9V
VFB=1V, VIN-=0.9V, V+=2.2V
VFB=1V, VIN-=1.1V
MIN.
TYP.
MAX.
UNIT
-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
0.29
0.44
100
40
17
0.35
0.5
–
50
25
0.41
0.56
–
60
33
V
V
%
%
%
PWM Comparate Block
Input Threshold Voltage
Maximum Duty Cycle
PWM/PFM Change Duty Cycle
Output Block
Output High Level
ON Resistance
Output Low Level
ON Resistance
General Characteristics
Quiescent Current
-4-
VT_25
VT_50
MAXDUTY_1
MAXDUTY_2
PFMDUTY
Duty= PFMDUTY
Duty=50%
VFB=0.9V
VFB=0.9V, RDTC=47kΩ
ROH
IO=-20mA
–
10
20
Ω
ROL
IO=+20mA
–
5
10
Ω
RL=Non Load
–
800
1200
µA
IDD
Ver.2012-08-03
NJU7631
■ TYPICAL APPLICATIONS
Step-Down Converter
FET
L
VIN
VOUT
CIN
SBD
COUT
NJU7631
GND
RT
7
FB
DTC
6
IN-
SCP
5
OUT
2
V
3
C
R1
8
1
+
Ver.2012-08-03
4
RT
RDTC
CS
CNF
RNF
R2
CSCP
-5-
NJU7631
■ TYPICAL CHARACTERISTICS
Oscillation Frequency vs. Timing Resistance
Oscillation Frequency fosc (kHz)
Oscillation Frequency fOSC (kHz)
1000
100
10
Oscillation Frequency vs. Operating Voltage
(V+=3.3V, Ta=25oC)
720
700
680
660
100
Timing Resistance RT (kΩ)
Duty Cycle vs. R
DTC
T
10
(Ta=25oC)
Reference Voltage V (V)
1.004
B
80
60
40
20
0
2
4
6
8
+
Operating Voltage V (V)
(V =3.3V, R =47kΩ, Ta=25 C)
AX
Duty Cycle M D
UTY
(%)
100
0
Reference Voltage vs. Operating Voltage
o
+
(RT=47kΩ, Ta=25oC)
740
1.002
1
0.998
0.996
0
20
40
60
80
100
Dead Time Control Resistance RDTC (kΩ)
0
2
4
6
8
Operating Voltage V+ (V)
10
Quiescent Current vs. Operating Voltage
(R =47kΩ, R =Non Load, Ta=25oC)
T
Quiescent Current IDD (µA)
1400
1200
1000
800
600
400
200
0
-6-
L
0
2
4
6
8
Operating Voltage V+ (V)
10
Ver.2012-08-03
NJU7631
■ TYPICAL CHARACTERISTICS
Error Amplifier Block
Voltage Gain, Phase vs. Frequency
+
o
(V =3.3V, Gain=40dB, Ta=25 C)
Gain
30
90
15
45
10
100
1000
Frequency f (kHz)
+
V =1.95V
8
Output Source Current IOM+ (mA)
V+=3.3V
6
4
V+=8V
2
0
-50
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
Error Amplifier Block
Output Source Current vs. Temperature
(VFB=1V, VIN-=0.9V)
V+=8V
100
V+=3.3V
10
V+=1.95V
1
-50
Ver.2012-08-03
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
0
10000
Output Block
Output Low Level ON Resistance
vs. Temperature (Io=+20mA)
12
10
10
1000
14
Output Sink Current IOM- (mA)
Output High Level ON Resistance
ROH (Ω)
1
Output Block
Output High Level ON Resistance
vs. Temperature (Io=-20mA)
12
135
Phase
0
0.1
14
180
Phase Φ (deg)
45
Output Low Level ON Resistance
ROL (Ω)
Voltage Gain Av (dB)
60
V+=1.95V
8
6
V+=3.3V
4
2
0
-50
0.2
0.15
V+=8V
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
Error Amplifier Block
Output Sink Current vs. Temperature
(VFB=1V, VIN- =1.1V)
V+=1.95V, 3.3V, 8V
0.1
0.05
0
-50
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
-7-
NJU7631
■ TYPICAL CHARACTERISTICS
Soft Start Time vs. Temperature
Reference Voltage vs. Temperature
+
(V =3.3V)
22
20
1.005
18
16
14
12
1
0.995
10
8
-50
0.99
-50
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
(V+=3.3V, RT=47kΩ)
2.06
740
Threshold Voltage (V)
Oscillator Frequency fOSC (kHz)
Oscillator Frequency vs. Temperature
760
720
700
680
660
640
-50
(V+=3.3V)
1.01
Reference Voltage VB (V)
Soft Start Time Tss (ms)
24
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
Under Voltage Lockout Block
vs. Temperature
2.02
VT_ON
1.98
1.94
VT_OFF
1.9
1.86
-50
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
Quiescent Current vs. Temperature
Quiescent Current IDD (µA)
1000
800
600
400
200
0
-50
-8-
(V+=3.3V, RT=47kΩ)
-25
0
25 50 75 100 125
o
Ambient Temperature Ta ( C)
Ver.2012-08-03
NJU7631
MEMO
[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.
Ver.2012-08-03
-9-
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