NCP4589 데이터 시트보기 (PDF) - ON Semiconductor
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NCP4589 Datasheet PDF : 30 Pages
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NCP4589
TYPICAL CHARACTERISTICS
6.45
4.30
2.15
Chip Enable
0.00
4.0
3.0
2.0
1.0
0.0
*1.0
0
IOUT = 50 mA
IOUT = 300 mA
IOUT = 1 mA
20 40 60 80 100 120 140 160 180 200
t (ms)
Figure 86. Shutdown, 3.3 V Version D,
VIN = 4.3 V
APPLICATION INFORMATION
A typical application circuit for NCP4589 series is shown
in Figure 87.
VIN
NCP4589
VOUT
VIN
VOUT
C1
1m
CE
C2
1m
AE
GND
Figure 87. Typical Application Schematic
Input Decoupling Capacitor (C1)
A 1 mF ceramic input decoupling capacitor should be
connected as close as possible to the input and ground pin of
the NCP4589. Higher values and lower ESR improves line
transient response.
Output Decoupling Capacitor (C2)
A 1 mF ceramic output decoupling capacitor is sufficient
to achieve stable operation of the IC. If tantalum capacitor
is used, and its ESR is high, the loop oscillation may result.
If output capacitor is composed from few ceramic capacitors
in parallel, the operation can be unstable. The capacitor
should be connected as close as possible to the output and
ground pin. Larger values and lower ESR improves dynamic
parameters.
Enable Operation
The enable pin CE may be used for turning the regulator
on and off. The regulator is switched on when CE pin voltage
is above logic high level. The enable pin has internal pull
down current source. If enable function is not needed
connect CE pin to VIN.
Current Limit
This regulator includes fold-back type current limit
circuit. This type of protection doesn’t limit current up to
current capability in normal operation, but when over
current occurs, the output voltage and current decrease until
the over current condition ends. Typical characteristics of
this protection type can be observed in the Output Voltage
versus Output Current graphs shown in the typical
characteristics chapter of this datasheet.
Output Discharger
The D version includes a transistor between VOUT and
GND that is used for faster discharging of the output
capacitor. This function is activated when the IC goes into
disable mode.
Auto ECO and Fast Mode
The NCP4589 has two operation modes that have impact
on supply current and transient response at low output
current. These two modes can be selected by AE pin. If AE
pin is at low level Auto ECO mode is available. Please, see
supply current vs. output current charts.
Thermal
As power across the IC increases, it might become
necessary to provide some thermal relief. The maximum
power dissipation supported by the device is dependent
upon board design and layout. Mounting pad configuration
on the PCB, the board material, and also the ambient
temperature affect the rate of temperature rise for the part.
That is to say, when the device has good thermal
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