Thermal Characteristics
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ZiLOG, Inc.
1H Year 2003
Thermal Characteristics
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DC03-0020
Page 1 of 6
Revision 2
Thermal Characteristics
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TABLE OF CONTENTS
Calculation of Device Junction Temperature............................................................................................3
Device θJA, θJC Table Summary Of Thermal Characteristics For ZiLOG Plastic Packages .................4
Device θJA, θJC Table Summary Of Thermal Resistance For Hermetic Packages ................................6
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DC03-0020
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Revision 2
Thermal Characteristics
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Thermal Characteristics
THERMAL CHARACTERISTICS
Calculation of Device Junction Temperature
Failure rates and Failures in Time (FITS) obtained from life test data are based on ambient temperatures
(TA), and are not corrected to junction temperature (TJ). However, when a significant difference
between TA and TJ exists, TJ can be incorporated into the Arrhenius Equation for accelerated failure
rates by using the following equations:
Junction Temp. (TJ):
TJ = (θJA) (PD) + TA
where:
θJA is the thermal resistance of junction with respect to ambient (C/W). PD is the
maximum power dissipation at TA in watts
and:
TA is the ambient temperature °C.
Case Temperature (TC):
where:
Illustration:
TC = TJ – (θJC) (PD)
θJC is the thermal resistance of junction with respect to case.
In order to calculate junction temperature (TJ) and case temperature (TC) for static
airflow for the Z86C04 in an 18L PDIP, we do the following:
1.
At 25°C, maximum power dissipation for this device is 0.08 watts.
2.
For our example, ambient temperature is denoted by TA and is assumed to be 25°C.
For the Z86C04 in plastic (copper); θJA and θJC are 75 and 18°C/watt respectively.
Therefore,
TJ = 75 x (0.08) + 25 = 31.2°C, and
TC = 31.2 – (18 x 0.08) = 29.8°C
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DC03-0020
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Thermal Characteristics
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Table 1-1. Device θJA, θJC Table Summary Of Thermal Characteristics For ZiLOG
Plastic Packages
Package Type
PDIP
18L
20L
28L
40L
42L
48L
52L
64L
PLCC
44L
68L
84L
QFP
44L
80L
100L
VQFP
64L
100L
SOIC
8L
18L
20L
28L
SSOP
20L
28L
48L
EPT SSOP
28
Package Code
P
θJA
θJC
Lead Frame
75
75
60
43
42
40
38
42
18
18
12
12
11
8
8
14
Cu
Cu
Cu
Cu
Cu
Cu
Cu
Cu
46
43
42
13
14
12
Cu
Cu
Cu
45
43
38
10
16
17
Cu
Cu
Cu
70
100
19
25
Cu
Cu
110
70
75
60
N/A
N/A
N/A
N/A
Cu
Cu
Cu
75
60
45
18
12
12
Cu
Cu
Cu
36
10
Cu
V
F
A
S
HZ
HT
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DC03-0020
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Thermal Characteristics
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Table 1-1. Device θJA, θJC Table Summary Of Thermal Characteristics For ZiLOG
Plastic Packages
Package Type
PDIP
LCC
44L
52L
68L
Package Code
P
L
θJA
θJC
53
48
40
7
10
6
Lead Frame
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DC03-0020
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Thermal Characteristics
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Table 1-2. Device θJA, θJC Table Summary Of Thermal Resistance For Hermetic
Packages
PBGA
256L
256L
CERDIP
28
40
48
Ceramic Side Braze
18
28
40
48
Ceramic Window
44L
Pin Grid Array
68L
Notes:
B
25
21
N/A
N/A
52
41
32
14
11
5
81
21
49
48
36
11
11
4
32
3
36
6
2 Layer
4 Layer
D
C
K
G
P=Plastic DIP
C=Ceramic DIP
D=Cerdip
L=LCC-Ceramic Leadless Chip Carrier
V=PLCC-Plastic Leaded Chip Carrier
F=QFP-Plastic Quad Flat Pack
A=VQFP-Very Small Quad Flat Pack
G=Ceramic Pin Grid Array
S=SOIC-Small Outline Integrated Circuit
B=PBGA-Plastic Ball Grid Array
HZ=SSOP-Shrink Small Outline Package
HT=EPT SSOP-Exposed Pad Thin SSOP
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DC03-0020
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Revision 2