aoz1038di Alpha & Omega Semiconductor, aoz1038di Datasheet - Page 9

• Manufacturer Part Number: aoz1038di
• Description: Ezbucktm 6 A Synchronous Buck Regulator
• Manufacturer: Alpha & Omega Semiconductor

The equation above can also be simplified to:
An easy-to-use application software which helps to
design and simulate the compensation loop can be found
at www.aosmd.com.
Thermal Management and Layout
Consideration
In the AOZ1038 buck regulator circuit, high pulsing
current flows through two circuit loops. The first loop
starts from the input capacitors, to the VIN pin, to the
LX pad, to the filter inductor, to the output capacitor
and load, and then return to the input capacitor through
ground. Current flows in the first loop when the high side
switch is on. The second loop starts from the inductor,
to the output capacitors and load, to the low side
NMOSFET. Current flows in the second loop when the
low side NMOSFET is on.
In the PCB layout, minimizing the area of the two loops
reduces the noise of the circuit and improves efficiency.
A ground plane is strongly recommended to connect the
input capacitor, output capacitor, and PGND pin of the
AOZ1038.
C
Rev. 1.2 February 2011
C
=
C
---------------------
O
R
×
C
R
L
www.aosmd.com
In the AOZ1038 buck regulator circuit, the major power
dissipating components are the AOZ1038 and the output
inductor. The total power dissipation of converter circuit
can be measured by input power minus output power.
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 AOZ1038 and thermal
impedance from junction to ambient.
The maximum junction temperature of AOZ1038 is
150 ºC, which limits the maximum load current capability.
The thermal performance of the AOZ1038 is strongly
affected by the PCB layout. Care should be taken during
the design process to ensure that the IC will operate
under the recommended environmental conditions.
P
T
P
junction
inductor_loss
total_loss
=
=
(
P
V
=
total_loss
IN
I
O
×
2
I
×
IN
R
–
–
inductor
P
V
inductor_loss
O
×
I
O
×
1.1
) Θ
AOZ1038
×
Page 9 of 14
JA