IP2004 Datasheet, PDF (8/15 Pages) International Rectifier – SYNCHRONOUS BUCK LGA POWER BLOCK

Data Sheet No. PD60322
iP2004
Calculating SOA Temperature:
(Figure 3)
(Figure 4)
(Figure 5)
(Figure 6)
(Figure 7)
SOA temperature adjustment for input voltage ≈ -0.5ºC
SOA temperature adjustment for output voltage ≈ 5.5ºC
SOA temperature adjustment for drive voltage (V_DD) ≈ -0.8 ºC
SOA temperature adjustment for output inductor ≈ 0.6 ºC
SOA temperature adjustment for switch frequency ≈ -1.9 ºC
TX axis intercept adjustment ≈ -0.5 ºC + 5.5 ºC - 0.8 ºC + 0.6 ºC - 1.9 ºC ≈ 2.9 ºC
Assuming T_PCB = 95ºC & T_CASE = 110ºC
The following example shows how the SOA current is adjusted for T_X increase of 2.9ºC
0
10
20
44
40
36
32
28
24
20
16
12
8
4
0
0
V_I = 12V
V_D = 5.0V
V_O = 1.3V
F_sw = 1MHz
L_O = 300nH
10
20
30
40
Case Temperature (ºC)
50
60
70
80
90
100 110
120 130
Safe
Operating
Area
Tx
30
40
50
60
70
80
90
100
110
120
130
PCB Temperature (ºC)
1. Draw a line from Case Temperature axis to the PCB Temperature axis.
2. Draw a vertical line from the T_X axis intercept to the SOA curve.
3. 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.
4. Draw a new vertical line from the T_X axis by adding or subtracting the SOA adjustment
temperature from the original T_X intercept point.
5. Draw a horizontal line from the intersection of the new 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 new SOA continuous current.
The SOA adjustment indicates the part is still allowed to run at a continuous current of 30A.
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12/22/2007