SX-A Family FPGAs
Thermal Characteristics
Introduction
The temperature variable in Actel Designer software refers to the junction temperature, not the ambient, case, or
board temperatures. This is an important distinction because dynamic and static power consumption will cause the
chip's junction to be higher than the ambient, case, or board temperatures.
EQ 2-9
and
EQ 2-10
give the relationship
between thermal resistance, temperature gradient and power.
T
J
–
T
A
θ
JA
=
----------------
P
EQ 2-9
T
C
–
T
A
-
θ
JA
=
-----------------
P
EQ 2-10
Where:
θ
JA
=
Junction-to-air thermal resistance
θ
JC
=
Junction-to-case thermal resistance
T
J
T
A
T
C
P
= Junction temperature
= Ambient temperature
= Ambient temperature
= total power dissipated by the device
Table 2-12 •
Package Thermal Characteristics
θ
JA
Package Type
Thin Quad Flat Pack (TQFP)
Thin Quad Flat Pack (TQFP)
Thin Quad Flat Pack (TQFP)
Plastic Quad Flat Pack (PQFP)
1
Plastic Quad Flat Pack (PQFP) with Heat Spreader
2
Plastic Ball Grid Array (PBGA)
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)
Fine Pitch Ball Grid Array (FBGA)
Notes:
1. The A54SX08A PQ208 has no heat spreader.
2. The SX-A PQ208 package has a heat spreader for A54SX16A, A54SX32A, and A54SX72A.
Pin
Count
100
144
176
208
208
329
144
256
484
θ
JC
14
11
11
8
3.8
3
3.8
3.8
3.2
Still Air
33.5
33.5
24.7
26.1
16.2
17.1
26.9
26.6
18
1.0 m/s
2.5 m/s
200 ft./min. 500 ft./min.
27.4
28
19.9
22.5
13.3
13.8
22.9
22.8
14.7
25
25.7
18
20.8
11.9
12.8
21.5
21.5
13.6
Units
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
v5.3
2-11
ACTEL [ Actel Corporation ]
