Datasheet

www.rohm.com

TSZ02201-0RAR1G200030-1-2

© 2012 ROHM Co., Ltd. All rights reserved.

29/40

20.Nov.2014 Rev.003

TSZ22111･15･00

BA4580Rxxx BA4584FV BA4584Rxx

Power Dissipation

Power dissipation(total loss) indicates the power that can be consumed by IC at TA =25℃(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℃/W. The temperature of IC inside the package can be estimated by this

thermal resistance. Figure 72. (a) 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

℃

/W

Derating curve in Figure 72. (b) 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. Figure 73. (c),(d)

show a derating curve for an example of BA4580Rxxx, BA4584FV, BA4584Rxx.

(Note 16)

(Note 17)

(Note 18)

(Note 19)

(Note 20)

(Note 21)

Unit

6.2

5.4

5.0

4.8

7.0

4.9

mW/℃

When using the unit above TA=25℃, subtract the value above per degree℃. Permissible dissipation is the value.

Permissible dissipation is the value when FR4 glass epoxy board 70mm ×70mm ×1.6mm (cooper foil area below 3%) is mounted.

Figure 73. Derating Curve

Figure 72. Thermal resistance and derating curve

θJA=(TJmax-TA)/ PD °C/W

Ambient Temperature TA [ °C ]

Chip Surface Temperature TJ [ °C ]

(a) Thermal Resistance

0

0.2

0.4

0.6

0.8

1

0

25

50

75

100

125

AMBIENT TEMPERATURE[℃]

BA4584RFV(Note 20)

BA4584FV(Note 21)

BA4584RF(Note 21)

(c)BA4580Rxxx

(d)BA4584FV/BA4584Rxx

(b) Derating Curve

Ambient Temperature TA [ °C ]

Power Dissipation of LSI [W]

PD(max)

θJA2 < θJA1

θ’JA1

θJA1

TJ’max

0

50

75

100

125

150

25

P1

P2

TJmax

θ’JA2 θ

JA2

0

0.2

0.4

0.6

0.8

1

0

25

50

75

100

125

AMBIENT TEMPERATURE [℃] .

BA4580RF(Note 16)

BA4580RFVM(Note 19)

BA4580RFVT(Note 18)

BA4580RFJ(Note 17)