Page 7 of 15 www.irf.com 12/22/2007
Data Sheet No. PD60322
iP2004
Calculating Power Loss and SOA for Different Operating Conditions
To calculate Power Loss for a given set of operation conditions, the following procedure
should be followed:
Power Loss Procedure
1. Determine the maximum current for each iP2004 and obtain the maximum power loss
from Figure 1
2. Use the Normalized curves in page 5 to obtain power loss values that match the
operating conditions in the Application
3. The maximum power loss under the Application conditions is then the product of the
power loss from Figure 1 and the normalized values.
To calculate the Safe Operating Area (SOA) for a given set of operating conditions, the
following procedure should be followed:
SOA Procedure
1. Determine the maximum PCB and CASE temperature at the maximum operating
current for each iP2004
2. Use the Normalized curves in page 5 to obtain SOA temperature adjustments that
match the operating conditions in the Application
3. Then, add the sum of the SOA temperature adjustments to the T
X
axis intercept in
Figure 2
Design Example
Operating Conditions:
Output Current = 30A Input Voltage = 10V Output Voltage = 3.3V
Switching Freq = 750kHz Inductor = 0.2µH Drive Voltage (V
DD
) = 5.5V
Calculating Maximum Power Loss:
(Figure 1) Maximum power loss = 8.0W
(Figure 3) Normalized power loss for input voltage ≈ 0.98
(Figure 4) Normalized power loss for output voltage ≈ 1.23
(Figure 5) Normalized power loss for drive voltage (V
DD
) ≈ 0.96
(Figure 6) Normalized power loss for output inductor ≈ 1.03
(Figure 7) Normalized power loss for switch frequency ≈ 0.91
Calculated Maximum Power Loss ≈ 8.0W x 0.98 x 1.23 x 0.96 x 1.03 x 0.91 ≈ 8.68W
