Table 14 shows typical maximum ambient temperatures in degrees Centigrade for a TQFP package used with a
2-layer board. The typical ambient temperatures are based on a 100-degree Centigrade maximum case
temperature. Figure 19 illustrates the typical temperatures in Table 14.
Table 14. Typical Ambient Temperatures for TQFP with Two-Layer Board
Linear Feet per Minute Airflow
Microcontroller
Speed
Typical Power
(Watts)
0 fpm
69.5
76.0
80.1
84.2
200 fpm
76.1
400 fpm
80.1
600 fpm
81.4
50 MHz
40 MHz
33 MHz
25 MHz
0.662
0.522
0.432
0.342
81.2
84.3
85.4
84.4
87.0
87.9
87.7
89.7
90.4
95
90
85
80
◆
◆
✶
●
◆
✶
●
◆
✶
●
■
■
✶
●
■
75
70
65
Legend:
■
■ 50 MHz
● 40 MHz
✵ 33 MHz
◆ 25 Mhz
0 fpm
200 fpm
600 fpm
400 fpm
Airflow (Linear Feet Per Minute)
Figure 19. Typical Ambient Temperatures for TQFP with Two-Layer Board
64
Am186TMER and Am188TMER Microcontrollers Data Sheet
AMD [ AMD ]
