IP2003APBF Datasheet, PDF (5/10 Pages) International Rectifier – Synchronous Buck Multiphase Optimized LGA Power Block Intergrated Power Semiconductors,Drivers&Passives

iP2003APbF
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.
Procedure
Case Temperature (ºC)
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10
20
30
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60
70
80
90
100
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120
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1) Draw a line from Case Temp axis at T_CASE to the PCB
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Temp axis at T_PCB.
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2) Draw a vertical line from the T_X axis intercept to the SOA
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curve.
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TX
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Safe
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Operating
3) Draw a horizontal line from the intersection of the vertical
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14
V_IN = 12V
Area
line with the SOA curve to the Y-axis. The point at which
12
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the horizontal line meets the Y-axis is the SOA current.
8
6
4
V_OUT = 1.3V
f_SW = 1MHz
L=0.3uH
2
0
0
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PCB Temperature (ºC)
Calculating Power Loss and SOA for Different Operating Conditions
To calculate power loss for a given set of operating conditions, the following procedure should be followed:
Determine the maximum current for each iP2003APbF and obtain the maximum power loss from Fig 1. Use the curves
in Figs. 3, 4, 5 and 6 to obtain normalized power loss values that match the operating conditions in the application. The
maximum power loss under the operating conditions is then the product of the power loss from Fig. 1 and the normal-
ized values.
To calculate the SOA for a given set of operating conditions, the following procedure should be followed:
Determine the maximum PCB temperature and Case temperature at the maximum operating current of each
iP2003APbF. Obtain the SOA temperature adjustments that match the operating conditions in the application from
Figs. 3, 4, 5 and 6. Then, add the sum of the SOA temperature adjustments to the Tx axis intercept in Fig 2.
The example below explains how to calculate maximum power loss and SOA.
Example:
Operating Conditions
Output Current = 40A
Sw Freq= 900kHz
Calculating Maximum Power Loss:
Input Voltage = 10V
Inductor = 0.2µH
Output Voltage = 3.3V
T_PCB = 100°C, T_CASE = 110°C
(Fig. 1)
(Fig. 3)
(Fig. 4)
(Fig. 5)
(Fig. 6)
Maximum power loss = 15W
Normalized power loss for input voltage ≈ 0.98
Normalized power loss for output voltage ≈ 1.14
Normalized power loss for frequency ≈ 0.94
Normalized power loss for inductor value ≈ 1.013
Calculated Maximum Power Loss for given conditions = 15W x 0.98 x 1.14 x 0.94 x 1.013 ≈ 15.96W
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