MIC5236 Просмотр технического описания (PDF) - Micrel
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MIC5236 Datasheet PDF : 12 Pages
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MIC5236
25°C, 50°C and 85°C. From these curves, the minimum
amount of copper can be determined by knowing the maxi-
mum power dissipation required. If the maximum ambient
temperature is 50°C and the power dissipation is as above,
632mW, the curve in Figure 7 shows that the required area
of copper is 25mm2.
The θJA of this package is ideally 63°C/W, but it will vary
depending upon the availability of copper ground plane to
which it is attached.
900
800 TJ = 125°C
700
85°C
50°C 25°C
600
500
400
300
200
100
00 0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Figure 7. Copper Area vs. Power-SOIC
Power Dissipation (TA)
700
600
500
400
300
200
100
00
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Figure 8. Copper Area vs. Power-MSOP
Power Dissipation (∆TJA)
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, see Figures 8 and 9.
900
800 TJ = 125°C
700
85°C 50°C 25°C
600
500
400
300
200
100
00 0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Micrel, Inc.
Figure 9. Copper Area vs. Power-MSOP
Power Dissipation (TA)
Power MSOP-8 Thermal Characteristics
The power-MSOP-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.
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 9, which shows safe
operating curves for three different ambient temperatures,
25°C, 50°C, and 85°C. From these curves, the minimum
amount of copper can be determined by knowing the maxi-
mum power dissipation required. If the maximum ambient
temperature is 50°C, and the power dissipation is 639mW,
the curve in Figure 9 shows that the required area of copper
is 110mm2,when using the power MSOP-8.
Adjustable Regulator Application
MIC5236BM/MM
2
3
VIN
IN OUT
VOUT
4
1 R1
EN ADJ
1µF
GND
R2
5-8
Figure 10. Adjustable Voltage Application
The MIC5236BM/MM can be adjusted from 1.24V to 20V by
using two external resistors (Figure 10). The resistors set the
output voltage based on the following equation:
R1
VOUT = VREF (1 + R2 )
Where VREF = 1.23V.
July 2005
11
MIC5236
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