ip2021c International Rectifier Corp., ip2021c Datasheet - Page 7

• Manufacturer Part Number: ip2021c
• Description: Synchronous Buck Dual Channel Power Block
• Manufacturer: International Rectifier Corp.

Applying the Safe Operating Area (SOA) Curve
The SOA graph incorporates power loss and thermal resistance information in a way that allows one
to solve for maximum current capability in a simplified graphical manner. It incorporates the ability to
solve thermal problems where heat is drawn out through the printed circuit board and the top of the
case. Please refer to International Rectifier Application Note AN1047 for further details on using this
SOA curve in your thermal environment.
Procedure
www.irf.com
1. Calculate (based on estimated Power Loss) or measure the Case temperature on the device
2. Draw a line from Case Temperature axis to the PCB Temperature axis.
3. Draw a vertical line from the T
4. Draw a horizontal line from the intersection of the vertical line with the SOA curve to the Y-axis
and the board temperature near the device (1mm from the edge).
(Output Current).
continuous current.
Figure 9 SOA Example, Continuous current  31A for T
The point at which the horizontal line meets the Y-axis is the SOA
X
axis intercept to the SOA curve.
8/13/2009
PCB
= 100ºC & T
iP2021CPbF
CASE
= 110ºC
PD-97414
7