BU2050F_16 Datasheet, PDF (7/15 Pages) Rohm – 4-input Serial-in / Parallel-out Drivers

BU2050F
I/O Equivalence Circuits
DATA,CLK,STB,CLR
VDD
VDD
DATA
CLK
STB
CLR
VSS
VSS
P1 to P8
VDD
P1 to P8
VSS
VSS
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 8 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 9 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.
θJA =( TJmax - TA)/ PD (°C/W)
Ambie周nt囲te温m度perTaatu[℃re] TA (℃)
Chip su_チrf_ッa_プce_表te_面m_温p_度era_Ttu_j r_[℃e T_] Jmax(℃)
Power dissipation PD (W)
消費電力 P [W]
Figure 8. Thermal resistance
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0
BU2050F(SOP14)
85
25 50 75 100 125
Ambient Temperature [℃]
Figure 9. Derating Curve
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TSZ22111・15・001
7/11
TSZ02201-0RHR1GZ00120-1-2
18.Apr.2016 Rev.003