MIC79050-4.2BM Micrel Inc, MIC79050-4.2BM Datasheet - Page 12

• Manufacturer Part Number: MIC79050-4.2BM
• Description: IC BATTERY CHARGER LI-ION 8-SOIC
• Manufacturer: Micrel Inc

Specifications of MIC79050-4.2BM

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 2.5 V ~ 16 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

temperature is +40°C and the power dissipation is as above,
0.46W, the curve in Figure 10 shows that the required area
of copper is 50mm
The θ
depending upon the availability of copper ground plane to
which it is attached.
MIC79050
MIC79050
JA
Figure 10. Copper Area vs. Power-SOIC
of this package is ideally 63°C/W, but it will vary
900
700
600
500
400
300
200
100
Power Dissipation (T
2
0
.
0
T
0.25 0.50 0.75 1.00 1.25 1.50
J
POWER DISSIPATION (W)
= 125°C
85°C
50°C 25°C
A
)
12
Power MSOP-8 Thermal Characteristics
The power-MSO-8 package follows the same idea as the
power-SO-8 package, using four ground leads with the die
attach paddle to create a single-piece electrical and thermal
conductor, reducing thermal resistance and increasing power
dissipation capability.
The same method of determining the heat sink area used
for the power-SOIC-8 can be applied directly to the power-
MSOP-8. The same two curves showing power dissipation
versus copper area are reproduced for the power-MSOP-8
and they can be applied identically.
Quick Method
Determine the power dissipation requirements for the design
along with the maximum ambient temperature at which the
device will be operated. Refer to Figure 12, which shows safe
operating curves for 3 different ambient temperatures, +25°C,
+50°C and +85°C. From these curves, the minimum amount
of copper can be determined by knowing the maximum power
dissipation required. If the maximum ambient temperature is
+25°C and the power dissipation is 1W, the curve in Figure
12v shows that the required area of copper is 500mm
using the power MSOP-8
Figure 12. Copper Area vs. Power-MSOP
Figure 11. Copper Area vs. Power-MSOP
Power Dissipation (ΔT
900
800
700
600
500
400
300
200
100
900
800
700
600
500
400
300
200
100
Power Dissipation (T
0
0
0
0
T J = 125°C
0.25 0.50 0.75 1.00 1.25 1.50
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
POWER DISSIPATION (W)
85°C
50°C 25°C
A
JA
)
)
August 2005
Micrel, Inc.
2
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