CMPWR330SA CALMIRCO [California Micro Devices Corp], CMPWR330SA Datasheet - Page 8

• Manufacturer Part Number: CMPWR330SA
• Description: 400mA SMARTOR Dual Regulator with V switch?
• Manufacturer: CALMIRCO [California Micro Devices Corp]

©2001 California Micro Devices Corp. All rights reserved. Smart OR™ is a trademark of California Micro Devices.
8
Typical Thermal Characteristics
The overall junction to ambient thermal resistance (θ
for device power dissipation (P
two paths in series. The first path is the junction to the
case (θ
second path is case to ambient (θ
which is dependent on board layout. The final operating
junction temperature for any set of conditions can be
estimated by the following thermal equation:
The CMPWR330 uses a thermally enhanced package
where all the GND pins (5 through 8) are integral to the
leadframe. When this package is mounted on a double
sided printed circuit board with two square inches of
copper allocated for “heat spreading”, the resulting θ
50°C/W.
Based on a maximum power dissipation of 0.7W
(1.75V x 0.4A) with an ambient of 70°C the resulting
junction temperature will be:
Thermal characteristics were measured using a double
sided board with two square inches of copper area
connected to the GND pins for “heat spreading”.
Measurements showing performance up to junction
temperature of 125°C were performed under light load
conditions (5mA). This allows the ambient temperature
to be representative of the internal junction temperature.
Note: The use of multi-layer board construction with
separate ground and power planes will further enhance
the overall thermal performance. In the event of no
copper area being dedicated for heat spreading, a multi-
layer board construction, using only the minimum size
pad layout, will typically provide the CMPWR330 with an
overall θ
safely dissipated.
215 Topaz Street, Milpitas, California 95035 
CALIFORNIA MICRO DEVICES
JC
JA
) which is defined by the package style, and the
T
T
JUNC
JUNC
of 70°C/W which allows up to 780mW to be
= T
= 70°C + 0.7W (50°C/W)
= 70°C + 35°C = 105°C
= T
= T
AMB
AMB
AMB
+ P
+ P
+ P
D
D
D
(θ
(θ
(θ
JA)
JC
JA
)
) + P
D
) consists primarily of
CA
D
) thermal resistance
(θ
CA
)
Tel: [phone]
JA
JA
)
is
Figure 24. Select/Deselect Threshold Variation with T
Figure 23. V
Figure 25. V
3.32
3.31
3.30
3.29
3.28
4.55
4.50
4.45
4.40
4.35
4.30
4.25
4.20
0.37
0.35
0.33
0.31
0.29
0.27
0.25
20
25
20
Fax: [phone]
V
DESELECT
OUT
V
SELECT
30
Variation with T
50
30
AUX
Switch Resistance vs T
Temperature (
Temperature (
Temperature (
40
75
40
100
50
50
AMB
˚
˚
˚
C)
C)
C)
www.calmicro.com
CMPWR330
(400mA Load)
125
60
60
AMB
150
70
70
JUNC
T
3/6/2001