NCP565, NCV565
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10
Table 1. Bill of Materials for NCP565 Adj Demonstration Board
Item Used # Component Designators Suppliers Part Number
1 4 Radial Lead Aluminum Capacitor
150 mF/16 V
C1, C2, C3, C5 Sanyo Oscon 16SA150M
2 1 Radial Lead Aluminum Capacitor
10 mF/10 V
C4 Sanyo Oscon 10SL10M
3 1 SMT Chip Resistor (0805) 15.8 K 1% R2 Vishay CRCW08051582F
4 1 SMT Chip Resistor (0805) 42.2 K 1% R1 Vishay CRCW08054222F
5 1 SMT Ceramic Capacitor (0603) 5.6 pF 10% C6 Vishay VJ0603A5R6KXAA
6 1 NCP565 Low Dropout Linear Regulator U1 ON Semiconductor NCP565D2TR4
Protection Diodes
When large external capacitors are used with a linear
regulator it is sometimes necessary to add protection diodes.
If the input voltage of the regulator gets shorted, the output
capacitor will discharge into the output of the regulator. The
discharge current depends on the value of the capacitor, the
output voltage and the rate at which V
in
drops. In the
NCP565 linear regulator, the discharge path is through a
large junction and protection diodes are not usually needed.
If the regulator is used with large values of output
capacitance and the input voltage is instantaneously shorted
to ground, damage can occur. In this case, a diode connected
as shown in Figure 24 is recommended.
V
in
V
out
NCP565
GND
Adj
C
1
C
Adj
R
1
R
2
1N4002 (Optional)
C
2
V
out
Figure 24. Protection Diode for Large
Output Capacitors
V
in
Thermal Considerations
This series contains an internal thermal limiting circuit
that is designed to protect the regulator in the event that the
maximum junction temperature is exceeded. This feature
provides protection from a catastrophic device failure due to
accidental overheating. It is not intended to be used as a
substitute for proper heat sinking. The maximum device
power dissipation can be calculated by:
P
D
+
T
J(max)
* T
A
R
qJA
Figure 25. Thermal Resistance
0 50 100 150 200 250 300 350 400 450 50
40
60
80
100
120
140
160
180
COPPER HEAT−SPREADER AREA (mm sq)
q
JA
°
DFN 1 oz Cu
DFN 2 oz Cu
SOT−223 1 oz Cu
SOT−223 2 oz Cu
D
2
PAK 1 oz Cu
D
2
PAK 2 oz Cu
