BU7461G_10 Datasheet, PDF (33/37 Pages) Rohm – Ground Sense Low Voltage Operation CMOS Operational Amplifiers

BU7461/BU7461S family, BU7441/BU7441S family, BU7462/BU7462S family, BU7442/BU7442S family
BU7464/BU7464S family, BU7444/BU7444S family, BU7465/BU7465S family, BU7445/BU7445S family Technical Note
●Derating curve
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 ship 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 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 θj-a[℃/W]. The temperature of IC inside the package can be estimated by
this thermal resistance. Fig.195 (a) shows the model of thermal resistance of the package. Thermal resistance θja, ambient
temperature Ta, junction temperature Tj, and power dissipation Pd can be calculated by the equation below:
θja = (Tj-Ta) / Pd [℃/W]
・・・・・ (Ⅰ)
Derating curve in Fig.195(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 iis 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. Fig196 (c)-(h) show a derating curve for an example Ground Sense Low Voltage
Operation CMOS Operational Amplifiers series.
[W]
Pd(max)
θja = ( Tj _ーTa ) / Pd [_℃/W]
P2
θja2 <θja1
Ambient temperature Ta [℃]
P1
θja2
Tj(max)
θja1
1000
800
600
400
Chip surface temperature Tj [℃]
Power dissipation P [W]
0
25
50
75
100
125
Ambient temperature Ta [℃]
(a) Thermal resistance
(b) Derating curve
Fig.195 Thermal resistance and derating
5 4 0 [ m W ] ^BU7461G(*26)
BU7441G(*26)
5 3 5 [ m W ] ^{BU7465HFV(*30)}
BU7445HFV(*30)
1000
800
600
400
620[mW] ^BU7462F(*27)
BU7442F(*27)
480[mW] BU7462FVM(*28)
BU7442FVM(*28)
412[mW] BU7462NUX(*29)
BU7442NUX(*29)
1000
800
600
400
4 8 8 [ m W ] BU7464F(*31)
BU7444F(*31)
200
200
200
0
0
1000
800
85
50
100
150
AMBIENT TEMPERATURE[℃]
(c) BU7461G BU7441G
BU7465HFV BU7445HFV
5 4 0 [ m W ] ^{BU7461SG(*26)}
BU7441SG(*26)
600
5 3 5 [ m W ] ^{BU7465SHFV(*30)}
BU7455SHFV(*30)
400
0
85
0
0
50
100
150
0
AMBIENT TEMPERATURE[℃]
(d) BU7462F/FVM/NUX BU7442F/FVM/NUX
1000
800
600
400
620[mW] BU7462SF(*27)
BU7442SF(*27)
480[mW] ^{BU7462SFVM(*28)}
BU7442SFVM(*26)
412[mW] ^{BU7462SNUX(*29)}
BU7442SNUX(*29)
1000
800
600
400
50
85 ₁₀₀
150
AM BIENT TEMPERATURE[℃]
(e) BU7464F BU7444F
4 8 8 [ m W ] ^{BU7461SG(*31)}
BU7441SG(*31)
200
200
200
0
105
0
50
100
150
AMBIENT TEMPERATURE[℃]
(f) BU7461SG BU7441SG
BU7465SHFV BU7445SHFV
0
0
105
0
50
100
150
0
AMBIENT TEMPERATURE[℃]
(g)BU7462S F/FVM/NUX BU7442S F/FVM/NUX
105
50
100
150
AMBIENT TEMPERATURE[℃]
(h) BU7464SF BU7444SF
(*26)
(*27)
(*28)
(*29)
(*30)
(*31)
5.4
6.2
4.8
4.12
5.35
4.88
When using the unit above Ta=25[℃], subtract the value above per degree[℃]. Permissible dissipation is the value.
When FR4 glass epoxy board 70[mm]×70[mm]×1.6[mm] (cooper foil area below 3[％]) is mounted.
Fig.196 Thermal resistance and derating
Unit
[mW/℃]
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2010.12 - Rev.A