
Am5
X
86 Microprocessor
65
AMD
PRELIMINARY
12
PACKAGE THERMAL
SPECIFICATIONS
The Am5
X
86 microprocessor is specified for operation
when T
CASE
(the case temperature) is within the range
of 0
°
C to +55
°
C or +85
°
C. T
CASE
can be measured in
any environment to determine whether the Am5
X
86 mi-
croprocessor is within specified operating range. The
case temperature should be measured at the center of
the top surface opposite the pins.
The ambient temperature (T
A
) is guaranteed if T
CASE
is
not violated. The ambient temperature can be calculated
from
θ
JC
and
θ
JA
and from the following equations:
T
J
= T
CASE
+ (P
θ
JC
)
T
A
= T
J
– (P
θ
JA
)
T
CASE
= T
A
+ (P [
θ
JA
–
θ
JC
])
Where:
T
J
, T
A
, T
CASE
θ
JC
,
θ
JA
= Junction, Ambient, and Case Temperature
= Junction-to-Case and Junction-to-Ambient
Thermal Resistance, respectively
= Maximum Power Consumption
P
The values for
θ
JA
and
θ
JC
are given in Table 21 for the
1.75 sq. in., 168-pin, ceramic PGA. For the 208-pin
SQFP plastic package,
θ
JA
= 14.0 and
θ
JC
= 1.5.
Table 22 shows the T
A
allowable (without exceeding
T
CASE
) at various airflows and T
CASE
values for the PGA
package. Note that T
A
is greatly improved by attaching
a heat sink to the package. P (the maximum power con-
sumption) is calculated by using a maximum I
CC
value
of 931 mA at 3.3 V. Table 23 shows the T
A
allowable
(without exceeding T
CASE
) for the SQFP package using
a maximum I
CC
value of 931 mA at 3.3 V.
Note:
*0.350
″
high unidirectional heat sink (Al alloy 6063-T5, 40 mil fin width, 155 mil center-to-center fin spacing)
Table 21. Thermal Resistance (°C/W)
θ
JC
and
θ
JA
for the Am5
X
86 CPU in 168-Pin PGA Package
θ
JA
vs. Airflow-Linear ft/min. (m/s)
0
(0)
(1.01)
No Heat Sink
1.5
16.5
14.0
Heat Sink*
2.0
12.0
7.0
Heat Sink* and fan
2.0
5.0
4.6
Cooling
Mechanism
θ
JC
200
400
(2.03)
12.0
5.0
4.2
600
(3.04)
10.5
4.0
3.8
800
(4.06)
9.5
3.5
3.5
1000
(5.07)
9.0
3.25
3.25
Table 22. Maximum T
A
at Various Airflows in
°
C
Airflow-Linear ft/min. (m/sec)
0
(0)
55
°
C
133 MHz
8.9
°
C
55
°
C
133 MHz
24.3
°
C
55
°
C
133 MHz
45.8
°
C
85
°
C
133 MHz
38.9
°
C
85
°
C
133 MHz
54.3
°
C
85
°
C
133 MHz
75.8
°
C
T
A
by Cooling Type
T
CASE
Clock
200
(1.01)
16.6
°
C
39.6
°
C
47.0
°
C
46.6
°
C
69.6
°
C
77.0
°
C
400
(2.03)
22.7
°
C
45.8
°
C
48.2
°
C
52.7
°
C
75.8
°
C
78.2
°
C
600
(3.04)
27.3
°
C
48.9
°
C
49.5
°
C
57.3
°
C
78.9
°
C
79.5
°
C
800
(4.06)
30.4
°
C
50.4
°
C
50.4
°
C
60.4
°
C
80.4
°
C
80.4
°
C
1000
(5.07)
32.0
°
C
51.2
°
C
51.2
°
C
62.0
°
C
81.2
°
C
81.2
°
C
T
A
without Heat Sink
T
A
with Heat Sink
T
A
with Heat Sink and fan
T
A
without Heat Sink
T
A
with Heat Sink
T
A
with Heat Sink and fan
Table 23. Maximum T
A
for SQFP Package by Clock Frequency
T
CASE
85
°
C
Clock
T
A
133 MHz
46.6
°
C