0

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0

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140

Board Temperature (°C)

1

2

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14

CSD87331Q3D

SLPS283B – SEPTEMBER 2011 – REVISED FEBRUARY 2017

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Copyright © 2011–2017, Texas Instruments Incorporated

Typical Application (continued)

In the design example above, the estimated power loss of the CSD87331Q3D would increase to 2.05 W. In

addition, the maximum allowable board and/or ambient temperature would have to decrease by 4.8°C. Figure 33

graphically shows how the SOA curve would be adjusted accordingly.

1. Start by drawing a horizontal line from the application current to the SOA curve.

2. Draw a vertical line from the SOA curve intercept down to the board/ambient temperature.

3. Adjust the SOA board/ambient temperature by subtracting the temperature adjustment value.

In the design example, the SOA temperature adjustment yields a reduction in allowable board/ambient

temperature of 4.8°C. In the event the adjustment value is a negative number, subtracting the negative number

would yield an increase in allowable board/ambient temperature.

Figure 33. Power Block SOA