○Product structure：Silicon monolithic integrated circuit ○This product is not designed protection against radioactive rays
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TSZ02201-0H1H0B100490-1-2
© 2012 ROHM Co., Ltd. All rights reserved.
18.DEC.2012 Rev.002
TSZ22111・14・001
BA6506F
www.rohm.com
●Thermal derating curve
Power dissipation (total loss) indicates the power that can be consumed by IC at Ta = 25ºC (normal temperature). IC is
heated when it consumes 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, etc, 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 in general equal to
the maximum value in the storage temperature range.
Heat generated by consumed power of IC is radiated from the mold resin or lead frame of package. The parameter which
indicates this heat dissipation capability (hardness of heat release) is called heat resistance, represented by the symbol θja
[℃/W]. The temperature of IC inside the package can be estimated by this heat resistance. Fig.11 shows the model of heat
resistance of the package.
Heat resistance θja, ambient temperature Ta, junction temperature Tj, and power consumption P can be calculated by the
equation below:
θja ＝ (Tj−Ta) / P [℃/W]
Thermal derating curve 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, packaging condition,
wind velocity, etc., even when the same package is used. Thermal derating curve indicates a reference value measured at
a specified condition. Fig.12 shows a thermal derating curve (Value when mounting FR4 glass epoxy board 70 [mm] x 70
[mm] x 1.6 [mm] (copper foil area below 3 [%]))
●Equivalent circuit
1) Hall input terminal 2) Output terminal 3)FG signal output terminal
Pd(mW)
700
600
500
400
300
200
100
02550
75 100 125 150
Ta(
℃
)
95
BA6506F
624
800
780
85
θja = (Tj-Ta) / P [℃/W]
Fig.11 Thermal resistance
Ambient temperature Ta[℃]
Chip surface temperature Tj[℃]
Power consumption
P[W]
H+ H-
1k
Ω
1k
Ω
Vcc
A1,A2
15k
Ω
FG
＊ Reduce by 6.24 mW/°C over 25°C.
(70.0mm×70.0mm×1.6mm glass epoxy board)
Fig.12 Thermal derating curve
