NCP4624(2012) View Datasheet(PDF) - ON Semiconductor
Part Name
Description
MFG CO.
NCP4624 Datasheet PDF : 18 Pages
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NCP4624
APPLICATION INFORMATION
A typical application circuit for NCP4624 series is shown
in the Figure 39.
VIN
C1
0.1mF
NCP4624x
VIN
VOUT
CE
GND
VOUT
C2
0.1mF
Figure 39. Typical Application Schematic
Input Decoupling Capacitor (C1)
A 100 nF ceramic input decoupling capacitor should be
connected as close as possible to the input and ground pin of
the NCP4624. Higher values and lower ESR improves line
transient response.
Output Decoupling Capacitor (C2)
A 100 nF 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. 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 IC is switched on when a high level voltage
is applied to the CE pin. The enable pin has an internal pull
down current source which assure off state of LDO in case
the CE pin will stay floating. If the enable function is not
needed connect CE pin to VIN.
The D version of the NCP4624 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.
Thermal Consideration
As a power across the IC increase, 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 increase for the
part. When the device has good thermal conductivity
through the PCB the junction temperature will be relatively
low in high power dissipation applications.
Reverse Current Protection Circuit
Internal Reverse Current Circuitry stops the reverse
current from VOUT pin to GND pin and VIN pin when
VOUT goes higher than VIN voltage or VSET voltage. VSET
means voltage given by voltage version. The parasitic diode
of PMOS pass device is internally switched to reverse
direction before VIN becomes lower than VOUT. The
operation coverage of the Reverse Current Protection
Circuit is VOUT > 1.5 V. In order to avoid unstable behavior
a hysteresis is created by different threshold of detecting
voltage VREV_DET and releasing voltage VREV_REL. See
Figures 40 and 41 for details of configuration.
Vin
Vout
Vin
Vout
Vref
Current
CE
Limit
Reverse Detector
CE
GND
Vref
Current
Limit
Reverse Detector
GND
Figure 40. Normal Operating Mode
Figure 41. Reverse Current Protection Mode
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