CM3102-12SO CALMIRCO [California Micro Devices Corp], CM3102-12SO Datasheet - Page 8

• Manufacturer Part Number: CM3102-12SO
• Description: Micropower 1.2V/150mA CMOS LDO Regulator with Power Good
• Manufacturer: CALMIRCO [California Micro Devices Corp]

Performance Information (cont’d)
CM3102-12ST/SO Typical Thermal Characteristics
The overall junction to ambient thermal resistance
(
rily of two paths in series. The first path is the junction
to the case (
and the second path is case to ambient (
resistance which is dependent on board layout. The
final operating junction temperature for any set of con-
ditions can be estimated by the following thermal equa-
tion:
The CM3102-12ST/SO uses a SOT23-5 package.
When this package is mounted on a double sided
printed circuit board with two square inches of copper
allocated for "heat spreading", the resulting
175°C/W.
Based on a maximum power dissipation of 315mW
(2.1Vx150mA), 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 pin for "heat spreading".
Measurements showing performance up to junction
temperature of 125°C were performed under light load
conditions (1mA). This allows the ambient temperature
to be representative of the internal junction tempera-
ture.
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 provide the CM3102-12ST/SO with
an overall
to be safely dissipated for the maximum junction tem-
perature.
© 2004 California Micro Devices Corp. All rights reserved.
8
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430 N. McCarthy Blvd., Milpitas, CA 95035-5112 L Tel: [phone]
) for device power dissipation (PD) consists prima-
T
JUNC
T
JUNC
θ
JA
θ
= T
= T
JC
= 70°C + 315mW X (175°C/W)
= 70°C + 55°C = 125°C
= T
of 175°C/W which allows up to 450mW
AMB
AMB
) which is defined by the package style,
AMB
+ P
+ P
+ P
D
D
(
(
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θ
JA
JC
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) + P
JA
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D
(
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) thermal
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is
L Fax: [phone]
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www.calmicro.com
CM3102
01/20/04