AOZ1300
Power Dissipation Calculation
Calculate the power dissipation for normal load condition
using the following equation:
P
D
= R
ON
x (I
OUT
)
2
The worst case power dissipation occurs when the load
current hits the current limit due to over-current or short
circuit faults. The power dissipation under these condi-
tions can be calculated using the following equation:
P
D
= (V
IN
– V
OUT
) x I
LIMIT
PCB Layout Guidelines
Proximity of passive devices and adequate power and
ground planes are critical for reliable operation of the
circuit. In general, use the top layer for the high current
connections and the bottom or inner layer for the quiet
connections such as GND. The power traces must be
as short and wide as possible, because of large current.
Long metal traces and component leads may cause
unwanted parasitic inductance and capacitance. In order
to achieve the best performance special care has to be
taken for proper grounding. A good practice is always the
use of a separate ground plane or at least a single point
ground structure. It is recommended to use a PCB with at
least two sides. It is very important to place the input and
output capacitor as close as possible to the pin of the
device.
Silk Screen Top
Top Layer
Bottom Layer
Rev. 1.3
August
2008
www.aosmd.com
Page 9 of 12
AOSMD [ ALPHA & OMEGA SEMICONDUCTORS ]
