Page 6 of 15

www.irf.com

12/22/2007

Data Sheet No. PD60322

iP2004

A

DC

V

Average

Input

Voltage

Average

Input

Current

P

P

P

P

DC

V

Average

VDD

Voltage

A

Average

VDD

Current

iP2004

V

IN

V

SW

P

GND

P

GND

NC

PWM

ENABLE

V

DD

V

SWS1

A

Average Output

Current

Averaging

Circuit

V

Average

Output

Voltage

V

SWS2

Figure 9 Power Loss Test Circuit

t

PDH

t

PDL

PWM

V

SW

90%

10%

90%

10%

Figure 10 Timing Diagram

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

1. Calculate (based on estimated Power Loss) or measure the Case temperature on the

device and the Board temperature near the device (1mm from the edge).

2. Draw a line from Case Temperature axis to the PCB Temperature axis.

4. Draw a horizontal line from the intersection of the vertical line with the SOA curve to

the Y-axis (Output Current). The point at which the horizontal line meets the Y-axis is

the SOA continuous current.

0

4

8

12

16

20

24

28

32

36

40

44

0

10

20

30

40

50

60

70

80

90

100

110

120

130

PCB Temperature (ºC)

Tx

0

10

20

30

40

50

60

70

80

90

100

110

120

130

Case Temperature (ºC)

Safe

Operating

Area

Figure 11 SOA Example, Continuous current

≈ 30A for T