P R E L I M I N A R Y
THERMAL CHARACTERISTICS
TQFP Package
The variable P is power in watts. Typical power supply
current (ICC) is TBD mA per MHz of clock frequency.
The Am186ES and Am188ES microcontrollers are
specified for operation with case temperature ranges
from 0°C to +100°C for a commercial device. Case
temperature is measured at the top center of the
package as shown in Figure 13. The various
temperatures and thermal resistances can be
determined using the equations in Figure 14 with
information given in Table 10.
θJA
θCA
TC
θJC
θJA is the total thermal resistance. θJA is the sum of θJC
the internal thermal resistance of the assembly, and
,
θJA = θJC + θCA
θCA, the case to ambient thermal resistance.
Figure 13. Thermal Resistance(°C/Watt)
θJA = θJC + θCA
P=ICC freq (MHz) VCC
TJ=TC+( P θJC
TJ=TA+ ( P θJA
)
)
TC=TJ–( P θJC
)
TC=TA+( P θCA
)
TA=TJ–( P θJA
)
TA=TC–( P θCA
)
Figure 14. Thermal Characteristics Equations
Table 10. Thermal Characteristics (°C/Watt)
Airflow
(Linear Feet
Package/Board
per Minute)
θJA
45
39
35
33
56
46
40
38
23
21
19
17
30
28
26
24
θJC
7
θCA
38
32
28
26
46
36
30
28
18
16
14
12
24
22
20
18
PQFP/2-Layer
0 fpm
200 fpm
400 fpm
600 fpm
0 fpm
7
7
7
TQFP/2-Layer
10
10
10
10
5
200 fpm
400 fpm
600 fpm
0 fpm
PQFP/4-Layer
to 6-Layer
200 fpm
400 fpm
600 fpm
0 fpm
5
5
5
TQFP/4-Layer
to 6-Layer
6
200 fpm
400 fpm
600 fpm
6
6
6
Am186/188ES and Am186/188ESLV Microcontrollers
55
AMD [ AMD ]
