BU7261G_10 Datasheet, PDF (33/37 Pages) Rohm – Full Swing Low Voltage Operation CMOS Operational Amplifiers

BU7261/BU7261S family, BU7241/BU7241S family, BU7295/BU7295S family, BU7275/BU7275S family
BU7262/BU7262S family, BU7242/BU7242S family, BU7264/BU7264S family, BU7244/BU7244S 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 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 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. Fig196(c) ~ (h)
show a derating curve for an example of low voltage full swing
CMOS Op-Amp.
[W]
Pd(max)
θja = ( Tj _ーTa ) / Pd [_℃/W]
P2
θja2 <θja1
Ambie^周nt^囲te^温m^度per^Ta^atu^[℃re^] Ta [℃]
P1
θja2
Tj(max)
θja1
1000
800
600
400
0
25
50
75
100
125
Chip suチrfッaプce表te面m温p度eraTtuj [r℃e ]Tj [℃]
Power_消di_費ss_電in_力] _{P [W]}
Ta[℃Am] bient temperature Ta [℃]
(a)Thermal resistance
(b) Derating curve
Fig. 195 Thermal resistance and derating
BU7261G(*26)
5 4 0 [ m W ] _BU7241G(*26)
5 3 5 [ m W ] ^{BU7295HFV(*30)}
BU7275HFV(*30)
1000
800
600
400
620[mW] BU7262F(*27)
BU7242F(*27)
480[mW] BU7262FVM(*28)
BU7242FVM(*28)
412[mW] BU7262NUX(*29)
BU7242NUX(*29)
1000
800
600
400
BU7264F(*31)
4 8 8 [ m W ] BU7244F(*31)
200
200
200
0
85
0
85
0
50
100
150
0
50
100
150
AMBIENT TEMPERATURE[℃]
AMBIENT TEMPERATURE[℃]
(c) BU7261G BU7241G
(d) BU7262F/FVM/NUX BU7242F/FVM/NUX
BU7275HFV BU7295HFV
0
0
50
85 ₁₀₀
150
AM BIENT TEMPERATURE[℃]
(e) BU7264F BU7244F
1000
800
600
400
540[mW]
BU7261SG(*26)
BU7241SG(*26)
5 3 5 [ m W ] ^{BU7295SHFV(*30)}
BU7275SHFV(*30)
1000
800
600
400
620[mW] _{BU7262SF(*27)}
BU7242SF(*27)
480[mW] BU7262SFVM(*28)
BU7242SFVM(*28)
412[mW] BU7262SNUX(*29)
BU7242SNUX(*29)
1000
800
600
400
488[mW]
BU7264SF(*31)
BU7244SF(*31)
200
200
200
0
105
0
50
100
150
AMBIENT TEMPERATURE[℃]
0
105
0
50
100
150
AMBIENT TEMPERATURE[℃]
0
105
0
50
100
150
AMBIENT TEMPERATURE[℃]
(f) BU7261SG BU7241SG
(g) BU7262S F/FVM/NUX BU7242S F/FVM/NUX
(h) BU7264SF BU7244SF
BU7275SHFV BU7295SHFV
(*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 Derating Curve
Unit
[mW/℃]
www.rohm.com
© 2010 ROHM Co., Ltd. All rights reserved.
33/36
2010.12 - Rev.A