NCP562, NCP563
APPLICATIONS INFORMATION
A typical application circuit for the NCP562 and NCP563
series are shown in Figure 1 and Figure 2.
Input Decoupling (C1)
Place external components, especially the output
capacitor, as close as possible to the circuit, and make leads
as short as possible.
Thermal
A 1.0
mF
capacitor either ceramic or tantalum is
recommended and should be connected close to the NCP562
package. Higher values and lower ESR will improve the
overall line transient response.
TDK capacitor: C2012X5R1C105K, or C1608X5R1A105K
Output Decoupling (C2)
The NCP562 and NCP563 are very stable regulators and
do not require any specific Equivalent Series Resistance
(ESR) or a minimum output current. Capacitors exhibiting
ESRs ranging from a few mW up to 10
W
can thus safely be
used. The minimum decoupling value is 0.1
mF
and can be
augmented to fulfill stringent load transient requirements.
The regulator accepts ceramic chip capacitors as well as
tantalum devices. Larger values improve noise rejection and
load regulation transient response.
TDK capacitor: C2012X5R1C105K, C1608X5R1A105K,
or C3216X7R1C105K
Enable Operation (NCP562 ONLY)
As power across the NCP562 and NCP563 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 effect the rate of temperature rise for
the part. This is stating that when the devices have good
thermal conductivity through the PCB, the junction
temperature will be relatively low with high power
dissipation applications.
The maximum dissipation the package can handle is
given by:
T
*T
A
PD
+
J(max)
R
qJA
The enable pin will turn on the regulator when pulled high
and turn off the regulator when pulled low. These limits of
threshold are covered in the electrical specification section
of this data sheet. If the enable is not used, then the pin
should be connected to V
in
.
Hints
If junction temperature is not allowed above the
maximum 125°C, then the NCP562 and NCP563 can
dissipate up to 250 mW @ 25°C.
The power dissipated by the NCP562 and NCP563 can be
calculated from the following equation:
Ptot
+
[Vin * Ignd (Iout)]
)
[Vin
*
Vout] * Iout
or
P
)
Vout * Iout
VinMAX
+
tot
Ignd
)
Iout
Please be sure the Vin and GND lines are sufficiently
wide. When the impedance of these lines is high, there is a
chance to pick up noise or cause the regulator to
malfunction.
If an 80 mA output current is needed then the ground
current from the data sheet is 2.5
mA.
For an NCP562 or
NCP563 (3.0 V), the maximum input voltage will then be
6.0 V.
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