Datasheet

Datasheet

7/12

BU4030B

BU4030BF

TSZ02201-0RDR1GZ00040-1-2

© 2013 ROHM Co., Ltd. All rights reserved.

09.Aug.2013 Rev.001

www.rohm.com

TSZ22111・15・001

Typical Performance Curves - continued

Power Dissipation

Power dissipation (total loss) indicates the power that can be consumed by IC at Ta=25°C (normal temperature). IC is heated

when it consumed power, and the temperature of IC chip becomes higher than ambient temperature. The temperature that

can be accepted by IC chip depends on circuit configuration, manufacturing process, and consumable power is limited.

Power dissipation is determined by the temperature allowed in IC chip (maximum junction temperature) and thermal

resistance of package (heat dissipation capability). The maximum junction temperature is typically equal to the maximum

value in the storage temperature range. Heat generated by consumed power of IC radiates from the mold resin or lead frame

of the package. The parameter which indicates this heat dissipation capability (hardness of heat release) is called thermal

resistance, represented by the symbol

θja (°C /W).The temperature of IC inside the package can be estimated by this

thermal resistance. Figure 10 shows the model of thermal resistance of the package. Thermal resistance

θja, ambient

temperature Ta, maximum junction temperature Tjmax, and power dissipation Pd can be calculated by the equation below:

θja = (Tjmax-Ta) / Pd

(°C /W)

Derating curve in Figure 11 indicates power that can be consumed by IC with reference to ambient temperature. Power that

can be consumed by IC with reference to ambient temperature. Power that can be consumed by IC begins to attenuate at

certain ambient temperature. This gradient is determined by thermal resistance

θja. Thermal resistance θja depends on chip

size, power consumption, package, ambient temperature, package condition, wind velocity, etc even when the same of

package is used. Thermal reduction curve indicates a reference value measured at a specified condition.

0

100

200

300

400

500

-50

-25

0

25

50

75

100

Ambient Temperature [°C]

Operating Temperature Range

Figure 10. Thermal resistance

周囲温度 Ta [℃]

チップ 表面温度 Tj [℃]

消費電力 P [W]

Ambient temperature Ta (℃)

Chip surface temperature Tj (℃)

Power dissipation Pd (W)

θja=(Tjmax-Ta)/Pd (°C /W)

Figure 11. Derating curve

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0

25

50

75

100

125

150

Ambient Temperature [

℃]

BU4030B (DIP14)

BU4030BF (SOP14)

85

1.18

0.56