P R E L I M I N A R Y
Table 17 shows typical maximum ambient temperatures in degrees Centigrade for a TQFP package used on a 4-
layer to 6-layer board. The typical ambient temperatures are based on a 100-degree Centigrade maximum case
temperature. Figure 18 graphically illustrates the typical temperatures in Table 17.
Table 17. Typical Ambient Temperatures (°C) for TQFP with a 4-Layer to 6-Layer Board
Linear Feet per Minute Airflow
Microcontroller
Speed
Typical Power
(Watts)
0 fpm
71.7
76.6
82.3
85.8
200 fpm
74.0
400 fpm
76.4
600 fpm
78.8
40 MHz
33 MHz
25 MHz
20 MHz
1.2
1.0
0.7
0.6
78.6
80.5
82.5
83.8
85.3
86.7
87.0
88.2
89.4
90
85
80
75
■
◆
■
◆
■
◆
■
◆
✶
●
✶
●
✶
●
✶
●
Legend:
70
65
● 40 MHz
✵ 33 MHz
◆ 25 Mhz
■ 20 MHz
0 fpm
200 fpm
600 fpm
400 fpm
Airflow (Linear Feet Per Minute)
Figure 18. Typical Ambient Temperatures for TQFP with a 4-Layer to 6-Layer Board
56
Am186ED/EDLV Microcontrollers
AMD [ AMD ]
