ProASICPLUS Flash Family FPGAs
Package Thermal Characteristics
The ProASICPLUS family is available in several package
types with a range of pin counts. Actel has selected
packages based on high pin count, reliability factors, and
superior thermal characteristics.
Thermal resistance defines the ability of a package to
conduct heat away from the silicon, through the
package to the surrounding air. Junction-to-ambient
thermal resistance is measured in degrees Celsius/Watt
and is represented as Theta ja (Θja). The lower the
thermal resistance, the more efficiently a package will
dissipate heat.
A package’s maximum allowed power (P) is a function of
maximum junction temperature (TJ), maximum ambient
operating temperature (TA), and junction-to-ambient
thermal resistance Θja. Maximum junction temperature is
the maximum allowable temperature on the active
surface of the integrated circuit (IC) and is 110°C. P is
defined as shown in EQ 2-4:
P = -T---J---–----T---A--
Θja
EQ 2-4
Θja is a function of the rate (in linear feet per minute
(lfpm)) of airflow in contact with the package. When the
estimated power consumption exceeds the maximum
allowed power, other means of cooling, such as
increasing the airflow rate, must be used. The maximum
power dissipation allowed for a Military temperature
device is specified as a function of Θjc. The absolute
maximum junction temperature is 150°C.
The calculation of the absolute maximum power
dissipation allowed for a Military temperature
application is illustrated in the following example for a
456-pin PBGA package:
Maximum Power Allowed
=
-M-----a---x---.---j-u---n----c--t---i-o---n-----t--e---m-----p----.-----(--°--C----)----–----M-----a---x---.---c---a---s--e-----t--e---m-----p---.----(--°--C-----)
θjc(°C/W)
=
-1---5---0----°---C-----–-----1---2---5----°---C--
3.0°C/W
=
8.333W
Table 2-16 • Package Thermal Characteristics
Plastic Packages
Thin Quad Flat Pack (TQFP)
Pin Count
100
θjc
14.0
Still Air
33.5
θja
1.0 m/s
200 ft./min.
27.4
2.5 m/s
500 ft./min.
25.0
Thin Quad Flat Pack (TQFP)
Plastic Quad Flat Pack (PQFP)1
PQFP with heat spreader2
144
11.0
33.5
28.0
208
8.0
26.1
22.5
208
3.8
16.2
13.3
25.7
20.8
11.9
Plastic Ball Grid Array (PBGA)
456
3.0
15.6
12.5
11.6
Fine Pitch Ball Grid Array (FBGA)
144
3.8
26.9
22.9
21.5
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)3
Fine Pitch Ball Grid Array (FBGA)4
256
3.8
26.6
22.8
484
3.2
18.0
14.7
484
3.2
20.5
17.0
21.5
13.6
15.9
Fine Pitch Ball Grid Array (FBGA)
676
3.2
16.4
13.0
12.0
Fine Pitch Ball Grid Array (FBGA)
896
2.4
13.6
10.4
9.4
Fine Pitch Ball Grid Array (FBGA)
1152
1.8
12.0
8.9
7.9
Ceramic Quad Flat Pack (CQFP)
208
2.0
22.0
19.8
18.0
Ceramic Quad Flat Pack (CQFP)
352
2.0
17.9
16.1
14.7
Ceramic Column Grid Array (CCGA/LGA)
624
6.5
8.9
8.5
8.0
Notes:
1. Valid for the following devices irrespective of temperature grade: APA075, APA150, and APA300
2. Valid for the following devices irrespective of temperature grade: APA450, APA600, APA750, and APA1000
3. Depopulated array
4. Full array
EQ 2-5
Units
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
v5.9
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