APL5605 Anpec Electronics Corporation, APL5605 Datasheet - Page 10

• Manufacturer Part Number: APL5605
• Description: 600ma Linear Regulator For Dc Fan Speed Control
• Manufacturer: Anpec Electronics Corporation

Application Information
Input Capacitor
The APL5605 requires proper input capacitors to supply
surge current during stepping load transients to prevent
the input rail from dropping. Because the parasitic induc-
tor from the voltage sources or other bulk capacitors to
the VIN limits the slew rate of the surge current, place the
Input capacitors near VIN as close as possible. Input
capacitors should be larger than 0.82 F.
Output Capacitor
The APL5605 needs a proper output capacitor to main-
tain circuit stability and to improve transient response
over temperature and current. In order to insure the cir-
cuit stability, the proper output capacitor value should be
larger than 1 F. With X5R and X7R dielectrics, 2.2 F is
sufficient at all operating temperatures. Maximum output
capacitor should be less than 330 F to insure the sys-
tem can be powered on effectively.
Operation Region and Power Dissipation
The APL5605 maximum power dissipation depends on
the thermal resistance and temperature difference be-
tween the die junction and ambient air. The power dissi-
pation P
where (T
junction and ambient air. θ
between Junction and ambient air. Assuming the T
and maximum T
the maximum power dissipation is calculated as:
For normal operation, do not exceed the maximum junc-
tion temperature rating of T
power dissipation should less than:
The GND provides an electrical connection to ground and
channels heat away. Connect the GND to ground by us-
ing a large pad or ground plane.
Copyright
Rev. A.1 - Jan., 2008
APL5605
D
J
-T
across the device is:
P
P
P
A
) is the temperature difference between the
D
D
D(max)
ANPEC Electronics Corp.
=(125-25)/80
J
=150 C (typical thermal limit threshold),
T (
= 1.56(W)
=(150-25)/80
= 1.25(W)
J
JA
T
A
)
JA
J
= 125 C. The calculated
is the thermal resistance
A
=25 C
10
Optimum performance can only be achieved when the
device is mounted on a PC board according to the SOP-8
Board Layout diagram.
PCB Layout Considerations
Figure 1 illustrates the layout. Below is a checklist for
your layout:
1. Please place the input capacitors close to the VIN
2. Ceramic capacitors for load must be placed near the
3. To place APL5605 and output capacitors near the load
4. Large current paths, the bold lines in figure 1, must
V
Recommanded Minimum Footprint
V
EN
IN
have wide tracks.
is good for performance.
load as close as possible
C
IN
GND
V
IN
8
1
VIN
0.050
EN
APL5605
SOP-8
7
2
GND
C
Figure 2
Figure 1
IN
Unit : Inch
GND
6
3
VOUT
VSET
For dissipating heat
V
0.024
OUT
5
4
C
OUT
www.anpec.com.tw
C
OUT
V
V
SET
OUT