Table 13 shows typical maximum ambient temperatures in degrees Centigrade for a PQFP package used with a
2-layer board. The typical ambient temperatures are based on a 100-degree Centigrade maximum case
temperature. Figure 18 illustrates the typical temperatures in Table 13.
Table 13. Typical Ambient Temperatures for PQFP with Two-Layer Board
Linear Feet per Minute Airflow
Microcontroller
Speed
Typical Power
(Watts)
0 fpm
74.81
80.2
200 fpm
78.8
400 fpm
81.43
85.4
600 fpm
82.8
50 MHz
40 MHz
33 MHz
25 MHz
0.662
0.522
0.432
0.342
83.3
86.5
83.56
87.0
86.2
87.9
88.7
89.1
90.4
91.1
94
92
◆
◆
90
◆
✶
●
88
86
✶
●
◆
✶
●
84
82
✶
●
■
■
80
■
78
76
Legend:
■ 50 MHz
● 40 MHz
✵ 33 MHz
◆ 25 Mhz
■
74
0 fpm
200 fpm
600 fpm
400 fpm
Airflow (Linear Feet Per Minute)
Figure 18. Typical Ambient Temperatures for PQFP with Two-Layer Board
Am186TMER and Am188TMER Microcontrollers Data Sheet
63
AMD [ AMD ]
