aoz1280 Alpha & Omega Semiconductor, aoz1280 Datasheet - Page 10

• Manufacturer Part Number: aoz1280
• Description: Ezbucktm 1.2 A Synchronous Buck Regulator
• Manufacturer: Alpha & Omega Semiconductor

The power dissipation in Schottky can be approximated
as:
where,
V
The power dissipation of inductor can be approximately
calculated by output current and DCR of inductor.
The actual junction temperature can be calculated with
power dissipation in the AOZ1280 and thermal
impedance from junction to ambient.
The maximum junction temperature of AOZ1280 is
150 ºC, which limits the maximum load current capability.
The thermal performance of the AOZ1280 is strongly
affected by the PCB layout. Extra care should be taken
by users during design process to ensure that the IC will
operate under the recommended environmental
conditions.
P
T
P
FW_Schottky
=
diode_loss
junction
Rev. 1.0 May 2011
inductor_loss
(
P
total_loss
is the Schottky diode forward voltage drop.
=
I
–
O
=
P
I
×
O
inductor_loss
2
(
1 D
×
–
R
inductor
) V
×
) Θ
FW_Schottky
×
×
1.1
JA
+
T
amb
www.aosmd.com
Several layout tips are listed below for the best electric
and thermal performance.
1. The input capacitor should be connected as close as
2. The inductor should be placed as close as possible
3. Keep the connection of the schottky diode between
4. Place the feedback resistors and compensation
5. Keep sensitive signal traces away from the LX pin.
6. Pour a maximized copper area to the VIN pin, the
7. Pour a copper plane on all unused board area and
possible to the VIN pin and the GND pin.
to the LX pin and the output capacitor.
the LX pin and the GND pin as short and wide
as possible.
components as close to the chip as possible.
LX pin and especially the GND pin to help thermal
dissipation.
connect the plane to stable DC nodes, like VIN,
GND or VOUT.
AOZ1280
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