P R E L I M I N A R Y
Table 15 shows typical maximum ambient temperatures in degrees Centigrade for a PQFP 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 17 graphically illustrates the typical temperatures in Table 15.
Table 15. Typical Ambient Temperatures for PQFP with a 4-Layer to 6-Layer Board
Linear Feet per Minute Airflow
Microcontroller
Speed
Typical Power
(Watts)
0 fpm
77.698
80.7247
85.3975
88.318
200 fpm
80.176
82.8664
87.02
400 fpm
82.654
600 fpm
85.132
87.1498
90.265
92.212
40 MHz
33 MHz
25 MHz
20 MHz
1.239
1.07085
0.81125
0.649
85.0081
88.6425
90.914
89.616
95
90
85
80
■
■
◆
■
◆
■
◆
✶
●
◆
✶
●
✶
●
✶
●
Legend:
75
70
● 40 MHz
✵ 33 MHz
◆ 25 Mhz
■ 20 MHz
0 fpm
200 fpm
600 fpm
400 fpm
Airflow (Linear Feet Per Minute)
Figure 17. Typical Ambient Temperatures for PQFP with a 4-Layer to 6-Layer Board
Am186/188ES and Am186/188ESLV Microcontrollers
59
AMD [ AMD ]
