NJW1933-T
600mA, 500kHz, Step-Down Switching Regulator
in SOT-23
GENERAL DESCRIPTION
The NJW1933 is a switching regulator IC for buck converter that
operates wide input voltage range from 4.5V to 40V. The wide input
range makes the NJW1933 suitable for several applications such as
12V and/or 24V industrial supplies, automotive batteries and the other
unregulated voltage sources.
It corresponds to Low ESR output capacitor (MLCC), high
operating frequency of 500kHz, internally compensated and small
SOT-23 package. Therefore, the NJW1933 can realize downsizing of
applications with a few and tiny external parts so that adopts current
mode control.
Also, it has a soft start function, over current protection and thermal
shutdown circuit.
■
PACKAGE OUTLINE
NJW1933F1
FEATURES
●
Pin compatible with LT1933 and LT2842. Also it is possible to reduce an external part
●
Maximum Rating Input Voltage:
45V
●
Wide Operating Voltage Range:
4.5 V to 40V
●
Switching Current:
0.8A (min.)
●
Fixed Operating Frequency:
500kHz (A-version)
●
Uses Tiny Capacitors and Inductors
●
Soft Start Function
●
Low Shutdown Current 1 A
●
Internally Compensated
●
Under Voltage Lockout (UVLO)
●
Output Adjustable Down to 1.25V
●
Over Current Protection / Thermal Shutdown Protection
●
Package Outline:
SOT-23-6-1
PIN CONFIGURATION
N.C. 1
GND 2
FB 3
NJW1933F1
6 SW
5 VIN
4 SHDN
Ver.2016-02-22
-1-
NJW1933-T
■
PIN DESCRIPTIONS
PIN NAME
N.C.
GND
FB
SHDN
VIN
SW
PIN
NUMBER
1
2
3
4
5
6
FUNCTION
Unused pin
GND pin
Output Voltage Detecting pin
Connects output voltage through the resistor divider tap to this pin in order to voltage
of the FB pin become 1.245V.
Standby Control pin
Normal Operation at the time of High Level. Standby Mode at the time of Low Level
or Open.
Power Supply pin for Power Line
Switch Output pin of Power MOSFET
■
BLOCK DIAGRAM
VIN
CURRENT
SENSE
UVLO
∑
OSC
OCP
SHDN
S
Q
Buffer
Soft
Start
R
TSD
FB
Error
AMP
PWM
SW
Vref
1.245V
GND
-2-
Ver.2016-02-22
NJW1933-T
■
ABSOLUTE MAXIMUM RATINGS
RATINGS
0.3 to 45
0.3 to 45
0.3 to 45
0.3 to 6
510 (*1)
Power Dissipation
P
D
mW
710 (*2)
Junction Temperature
T
j
40 to 150
C
Operating Temperature
T
opr
40 to 105
C
Storage Temperature
T
stg
50 to 150
C
(*1): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JDEC standard, 2Layers)
(*2): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JDEC standard, 4Layers),
internal Cu area: 74.2×74.2mm
PARAMETER
Input Voltage
VIN-SW pin voltage
SHDN Voltage
Feedback Pin Voltage
SYNBOL
V
IN
V
V-SW
V
SHDN
V
FB
(Ta=25 C)
UNIT
V
V
V
V
■
RECOMMENDED OPERATING CONDITION
PARAMETER
Input Voltage
SYMBOL
V
IN
MIN.
4.5
TYP.
–
MAX.
40
(T
a
=25ºC)
UNIT
V
Ver.2016-02-22
-3-
NJW1933-T
■
ELECTRICAL CHARACTERISTICS
(Specifications in standard type face are for Ta= 25°C and those with boldface type apply over the bellow Operating
Temperature Range (Ta= 40°C to 105°C). Minimum and Maximum specs are guaranteed through test. Unless
otherwise noted, V
IN
= V
SHDN
=12V, Ta= 25°C)
PARAMETER
SYMBOL
CONDITIONS
MIN.
TYP.
MAX. UNIT
Under Voltage Lockout Block
ON Threshold Voltage
OFF Threshold Voltage
Hysteresis Width
Oscillation Block
Oscillation Frequency1
Oscillation Frequency2
Error Amplifier Block
Feedback Voltage
FB Pin Bias Current
PWM Comparator Block
Maximum Duty Cycle
Minimum ON Time
V
T_ON
V
T_OFF
V
HYS
V
IN
= L
V
IN
= H
H
L
4.2
4.1
–
4.35
4.25
100
4.5
4.4
–
V
V
mV
f
OSC1
f
OSC2
V
FB
=1.1V
V
FB
=0V
400
–
500
80
600
–
kHz
kHz
V
B
I
B
V
FB
=1.3V
1.6
–
1.245
10
1.6
100
V
nA
M
AX
D
UTY
t
ON_min
V
FB
=1.1V
88
–
94
100
–
160
ns
Output Block
Switching Current Limit
Output ON Resistance
Switch Leakage Current
SHDN Block
SHDN ON Control Voltage
SHDN OFF Control Voltage
SHDN Bias Current1
SHDN Bias Current2
General
Quiescent Current1
Quiescent Current2
Quiescent Current in SHDN
I
LIM
R
ON
I
LEAK
I
SW
=400mA
V
SHDN
= 0V, V
IN
=45V, V
SW
=0V
0.8
–
–
1.1
1
–
1.5
1.6
1
A
A
V
SHDN(ON)
V
SHDN(OFF)
I
SHDN_BIAS1
I
SHDN_BIAS2
V
SHDN
= L H
V
SHDN
= H L
V
SHDN
= 2.3V
V
SHDN
= 0V
2.3
0
–
–
–
–
5
0.01
V
IN
0.3
10
0.1
V
V
A
A
I
DD1
I
DD2
I
DD_SHDN
Not Switching, V
FB
=1.3V
No Load, V
FB
=1.1V
V
SHDN
= 0V
–
–
–
1.6
2.2
–
2.5
3.2
1
mA
mA
A
-4-
Ver.2016-02-22
NJW1933-T
THERMAL CHARACTERISTICS
PARAMETER
SYMBOL
VALUE
UNIT
Junction-to-ambient
245 (*3)
ja
C/W
thermal resistance
175 (*4)
Junction-to-Top of package
70 (*3)
jt
C/W
characterization parameter
60 (*4)
(*3): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JDEC standard, 2Layers)
(*4): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JDEC standard, 4Layers),
internal Cu area: 74.2×74.2mm
POWER DISSIPATION vs. AMBIENT TEMPERATURE
NJW1933F1
Power Dissipation vs. Ambient Temperature
(Topr=-40 to +105ºC, Tj= ~150ºC)
800
*4) At on 4-layer PC Board
700
Power Dissipation P
D
[mW]
600
*3) At on 2-layer PC Board
500
400
300
200
100
0
-50
-25
0
25
50
75
100 125 150
Ambient Temperature Ta [ºC]
Ver.2016-02-22
-5-
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