Table 15 shows typical maximum ambient temperatures in degrees Centigrade for a PQFP package used with a
4-layer to 6-layer board. The typical ambient temperatures are based on a 100-degree Centigrade maximum case
temperature. Figure 20 illustrates the typical temperatures in Table 15.
Table 15. Typical Ambient Temperatures for PQFP with Four-Layer to Six-Layer Board
Linear Feet per Minute Airflow
Microcontroller
Speed
Typical Power
(Watts)
0 fpm
88.0
90.6
92.3
93.8
200 fpm
89.4
400 fpm
90.7
600 fpm
92.0
50 MHz
40 MHz
33 MHz
25 MHz
0.662
0.522
0.432
0.342
91.6
92.7
93.7
93.1
93.9
94.9
94.5
95.2
95.9
97
96
◆
◆
95
✶
●
◆
94
93
✶
●
◆
✶
●
✶
92
91
■
■
●
90
■
89
88
Legend:
■ 50 MHz
● 40 MHz
✵ 33 MHz
◆ 25 Mhz
■
87
0 fpm
200 fpm
600 fpm
400 fpm
Airflow (Linear Feet Per Minute)
Figure 20. Typical Ambient Temperatures for PQFP with Four-Layer to Six-Layer Board
Am186TMER and Am188TMER Microcontrollers Data Sheet
65
AMD [ AMD ]
