aoz1242 Alpha & Omega Semiconductor, aoz1242 Datasheet - Page 11

• Manufacturer Part Number: aoz1242
• Description: Ezbucktm 3a Simple Buck Regulator
• Manufacturer: Alpha & Omega Semiconductor

The power dissipation of the diode is:
The actual AOZ1242 junction temperature can be
calculated with power dissipation in the AOZ1242 and
thermal impedance from junction to ambient.
The maximum junction temperature of AOZ1242 is
145°C, which limits the maximum load current capability.
The thermal performance of the AOZ1242 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
Rev. 1.4 November 2010
diode_loss
junction
+ +
=
=
(
P
I
T
total_loss
O
ambient
×
V
F
×
–
⎛
⎜
⎝
P
1
inductor_loss
–
-------- -
V
V
IN
O
⎞
⎟
⎠
) Θ
×
JA
www.aosmd.com
Several layout tips are listed below for the best electric
and thermal performance. Figure 3a and Figure 3b give
the example of layout for AOZ1242A and AOZ1242D
respectively.
1. Do not use thermal relief connection to the V
2. Input capacitor should be connected to the V
3. Make the current trace from LX pins to L to Co to the
4. Pour copper plane on all unused board area and
5. Keep sensitive signal trace such as trace connected
the GND pin. Pour a maximized copper area to the
GND pin and the V
and the GND pin as close as possible.
GND as short as possible.
connect it to stable DC nodes, like V
V
with FB pin and COMP pin far away form the LX pins.
OUT
.
IN
pin to help thermal dissipation.
IN
, GND or
AOZ1242
Page 11 of 18
IN
IN
and
pin