AM186EM Datasheet, PDF (54/98 Pages) List of Unclassifed Manufacturers – MICROCONTROLLER BLOCK DIAGRAM

PRELIMINARY
THERMAL CHARACTERISTICS
TQFP Package
The Am186EM and Am188EM microcontrollers are
specified for operation with case temperature ranges
from 0°C to +100°C for a commercial temperature de-
vice. Case temperature is measured at the top center
of the package as shown in Figure 15. The various tem-
peratures and thermal resistances can be determined
using the equations in Figure 16 with information given
in Table 8.
θ_JA is the sum of θ_JC and θ_CA. θ_JC is the internal ther-
mal resistance of the assembly. θ_CA is the case to am-
bient thermal resistance.
The variable P is power in watts. Typical power
supply current (I_CC) for the Am186EM and Am188EM
microcontrollers is 5.9 mA per MHz of clock frequency.
θ_JA
θ_CA
T_{C θJC}
θ_JA = θ_JC + θ_CA
Figure 15. Thermal Resistance(°C/Watt)
θ_JA = θ_JC + θ_CA
P=5.9 mA ⋅ freq (MHz) ⋅V_CC
T_J=T_C+( P⋅θ_JC )
T_J=T_A+ (P⋅θ_JA )
T_C=T_J–( P⋅θ_JC )
T_C=T_A+( P⋅θ_CA )
T_A=T_J–( P⋅θ_JA )
T_A=T_C–( P⋅θ_CA )
Figure 16. Thermal Characteristics Equations
Table 8. Thermal Characteristics (°C/Watt)
Airflow
(Linear Feet
θ_JC
θ_CA
θ_JA
Package/Board per Minute)
0 fpm
7
38
45
PQFP/2-Layer
200 fpm
400 fpm
7
32
39
7
28
35
600 fpm
7
26
33
0 fpm
10
46
56
TQFP/2-Layer
200 fpm
400 fpm
10
36
46
10
30
40
600 fpm
10
28
38
0 fpm
5
18
23
PQFP/4-Layer
to 6-Layer
200 fpm
400 fpm
5
16
21
5
14
19
600 fpm
5
12
17
0 fpm
6
24
30
TQFP/4-Layer
to 6-Layer
200 fpm
400 fpm
6
22
28
6
20
26
600 fpm
6
18
24
54
Am186/188EM and Am186/188EMLV Microcontrollers