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
●
Uses Tiny Capacitors and Inductors
●
Soft Start Function
●
Low Shutdown Current
<
1µA
●
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
6
5
4
NJW1933
1
2
3
Pin Function
1. N.C.
2. GND
3. FB
4. SHDN
5. V
IN
6. SW
Ver.2013-05-07
-1-
NJW1933-T
■
ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYNBOL
Input Voltage
V
IN
+
V -SW pin voltage
V
V-SW
SHDN Voltage
V
SHDN
Feedback Pin Voltage
V
FB
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
+85
°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
■
RECOMMENDED OPERATING CONDITION
(Ta=25°C)
UNIT
V
V
V
V
PARAMETER
Input Voltage
SYMBOL
V
IN
MIN.
4.5
TYP.
–
MAX.
40
(T
a
=25ºC)
UNIT
V
Ver.2013-05-07
-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
=12V, Ta=+25°C)
PARAMETER
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
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 Curent1
Quiescent Current2
Quiescent Current in SHDN
SYMBOL
CONDITIONS
MIN.
TYP.
MAX.
UNIT
V
T_ON
V
T_OFF
V
HYS
f
OSC1
f
OSC2
V
B
I
B
M
AX
D
UTY
t
ON_min
V
IN
= L
→
H
V
IN
= H
→
L
4.2
4.1
–
4.35
4.25
100
4.5
4.4
–
V
V
mV
V
FB
=1.1V
V
FB
=0V
400
–
−1.6%
–
500
80
600
–
+1.6%
100
kHz
kHz
V
FB
=1.3V
V
FB
=1.1V
1.245
10
V
nA
%
ns
88
–
94
100
–
160
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
Ω
µA
V
SHDN(ON)
V
SHDN(OFF)
I
SHDN_BIAS1
I
SHDN_BIAS2
V
SHDN
= 2.3V
V
SHDN
= 0V
2.3
–
–
–
–
–
5
0.01
–
0.3
10
0.1
V
V
µA
µA
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
µA
-4-
Ver.2013-05-07
嵌入式系统
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