APL5336 Anpec Electronics Corporation, APL5336 Datasheet - Page 12

• Manufacturer Part Number: APL5336
• Description: Source And Sink, 1.5a, Fast Transient Response Linear Regulator
• Manufacturer: Anpec Electronics Corporation

APL5336
Application Information
Power Sequencing
The input sequence of powers applied for VIN and VCNTL
is not necessary to be concerned.
Reference Voltage
A reference voltage is applied at the VREF pin by a resis-
tor divider between VIN and GND pins. An external by-
pass capacitor is also connected to VREF. The capacitor
and the resistor divider form a low-pass filter to reduce
the inherent reference noise from VIN. The capacitor is a
0.1 F or greater ceramic capacitor and connected as close
to VREF as possible. More capacitance and large resis-
tor divider will increase the soft-start interval. Do not place
any additional loading on this reference input pin.
Input Capacitor
The APL5336 requires proper input capacitors to supply
current surge during stepping load transients to prevent
the input rail from dropping. Because the parasitic induc-
tors from the voltage sources or other bulk capacitors to
the VIN pin limit the slew rate of the input current, more
parasitic inductance needs more input capacitance. For
the APL5336, the total capacitance of input capacitors
value including MLCC and aluminum electrolytic capaci-
tors should be larger than 10 F.
For VCNTL pin, a capacitor of 0.47 F (MLCC) or above is
recommended for noise decoupling.
Output Capacitor
The APL5336 needs a proper output capacitor to main-
tain circuit stability and improve transient response. In
order to insure the circuit stability, a 10 F X5R or X7R
MLCC output capacitor is sufficient at all operating tem-
peratures and it must be placed near the VOUT. The maxi-
mum distance from output capacitor to VOUT must within
10mm. Total output capacitors value including MLCC and
aluminum electrolytic capacitors should be larger than
10 F.
Copyright
Rev. A.2 - Apr., 2008
ANPEC Electronics Corp.
12
Table 1 provides the suitable output capacitors for
APL5336
Table 1: Output Capacitor Guide
Operation Region and Power Dissipation
The APL5336 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.
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 of T
sipation should less than:
PCB Layout Consideration
Figure 1 illustrates the layout. Below is a checklist for
your layout:
Murata website: www.murata.com
1. Please place the input capacitors close to the VIN.
2. Please place the output capacitors close to the VOUT,
3. To place APL5336 and output capacitors near the load
Vendor
Murata
a MLCC capacitor larger than 8 F must be placed
near the VOUT. The distance from VOUT to output
MLCC must be less than 10mm.
is good for load transient response.
P
P
P
D
D
D
. 1
. 1
(max)
56
25
D
T (
(
J
across the device is:
125
-T
(
(
J
W
W
A
JA
80
) is the temperature difference between the
(
10 F, 6.3V, X7R, 0805, GRM21BR70J106K
10 F, 6.3V, X5R, 0805, GRM21BR60J106K
)
)
150
T
A
25
J
80
)
=150
)
25
J
= 125
o
)
C (typical thermal limit threshold),
o
Description
JA
C. The calculated power dis-
is the thermal resistance
www.anpec.com.tw
A
=25
o
C