AX500-1BG896 ACTEL [Actel Corporation], AX500-1BG896 Datasheet - Page 20

• Manufacturer Part Number: AX500-1BG896
• Description: Axcelerator Family FPGAs
• Manufacturer: ACTEL [Actel Corporation]

Thermal Characteristics
Introduction
The temperature variable in Actel’s Designer software refers to the junction temperature, not the ambient
temperature. This is an important distinction because dynamic and static power consumption cause the chip junction
temperature to be higher than the ambient temperature.
Where:
Package Thermal Characteristics
The device junction-to-case thermal characteristic is θ
thermal characteristics for θ
absolute maximum junction temperature is 125°C.
The maximum power dissipation allowed for commercial- and industrial-grade devices is a function of
calculation of the absolute maximum power dissipation allowed for an 896-pin FBGA package at commercial
temperature and still air is as follows:
The maximum power dissipation allowed for Military temperature and Mil-Std 883B devices is specified as a function
of θ
Table 2-6 • Package Thermal Characteristics
2 -6
Package Type
Chip Scale Package (CSP)
Plastic Quad Flat Pack (PQFP)
Plastic Ball Grid Array (PBGA)
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)
Ceramic Quad Flat Pack (CQFP)
Ceramic Quad Flat Pack (CQFP)
Ceramic Column Grid Array (CCGA)
Notes:
1. θ
2. θ
Axcelerator Family FPGAs
T
T
ΔT = Temperature gradient between junction
jc
resistance from junction to board (θ
J
a
jc
jc
.
= Junction Temperature = ΔT + T
for the 208-pin and 352-pin CQFP refers to the thermal resistance between the junction and the bottom of the package.
for the 624-pin CCGA refers to the thermal resistance between the junction and the top surface of the package. Thermal
= Ambient Temperature
Maximum Power Allowed
(silicon) and ambient
1
1
ja
are shown with two different air flow rates. θ
2
=
Max. junction temp. (°C) Max. ambient temp. (°C)
-------------------------------------------------------------------------------------------------------------------------------------- -
jb
a
) for CCGA 624 package is 3.4
Pin Count
1152
180
208
729
256
324
484
676
896
208
352
624
EQ 2-1
θ
ja
(°C/W)
jc
N/A
8.0
2.2
3.0
3.0
3.2
3.2
2.4
1.8
2.0
2.0
6.5
v2.7
θ
–
, and the junction-to-ambient air characteristic is θ
jc
EQ 2-1
Where:
°
C/W.
ΔT = θ
θ
P
θ
can be used to calculate junction temperature.
ja
ja
Still Air
57.8
13.7
26.6
25.8
20.5
16.4
13.6
12.0
17.9
8.9
26
22
= Power
= Junction to ambient of package. θ
ja
* P
are located under
jc
values are provided for reference. The
θ
ja
=
51.0
23.5
10.6
22.8
22.1
17.0
13.0
10.4
19.8
16.1
1.0m/s
8.9
8.5
125°C 70°C
------------------------------------
13.6°C/W
–
Table 2-6 on page
θ
ja
21.5
20.9
15.9
12.0
=
20.9
18.0
14.7
2.5m/s
9.6
9.4
7.9
50
8
4.04 W
θ
ja
ja
. A sample
numbers
2-6.
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
ja
EQ 2-2
. The