BU2505FV_15 Datasheet, PDF (13/22 Pages) Rohm – 10bit 8ch/10ch D/A Converters

BU2505FV BU2506FV
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 13(a) shows the model of thermal resistance of the package. Thermal resistance θJA, ambient
temperature TA, junction temperature TJmax, and power dissipation PD can be calculated by the equation below
θJA = (TJmax - TA) / PD °C /W
Derating curve in Figure 13(b) indicates 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 14(a) show a derating curve for an example of BU2505FV and BU2506FV.
θJA =(TJmax-TA)/P °C /W
Ambient temperature TA[°C]
周囲温度 Ta [℃]
PPoL^owS^weI^eのrrd消^disis費ssiip電^paat力^tiioonn[Wo]f ^{LLSSII [}の^W消^]
費電力
P_PD_d(m₍a_mx)_ax)
P2
θ_θJ_jaA₂2 <_<θ_θJ_jA_a1₁
P1
θ_θ’_'JA_ja2_{2 θθJjAa22}
θ_θ’J_'A_j1_{a1 θθJjaA11}
Tj ' (^Tm^’Ja^mx^a)^{x T}T^Jj^m(^am^x ax)
Chip surfaceチtッeプm表pe面ra温tu度reTTjJ[[℃°C] ]
消費電力 P [W]
(a) Thermal Resistance
0
25
50
75 100 125 150
tempAemrabtuierenAt周^m周teb囲^囲mie温^p温net度^{度ratuTTraAe[T[℃°AC][°]C]}
(b) Derating Curve
Figure 13. Thermal resistance and derating
curve
(a) BU2505FV・BU2506FV
Derating curve
UNIT
7.5
mW/°C
When using the IC above TA=25°C, subtract the value above per °C
Mounted on a FR4 glass epoxy board 70mm x 70mm x 1.6mm (cooper foil area less than 3%).
Figure 14. Derating curve
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TSZ22111・15・001
13/18
TSZ02201-0RLR0GZ10140-1-2
11.Dec.2015 Rev.001