A3P1000-1FGG144M Datasheet, PDF (19/181 Pages) Actel Corporation – Military ProASIC3/EL Low-Power Flash FPGAs

Military ProASIC3/EL Low-Power Flash FPGAs
Thermal Characteristics
Introduction
The temperature variable in the Actel 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.
EQ 2-1 can be used to calculate junction temperature.
T_J = Junction Temperature = ΔT + T_A
EQ 2-1
where:
T_A = Ambient Temperature
ΔT = Temperature gradient between junction (silicon) and ambient ΔT = θ_ja * P
θ_ja = Junction-to-ambient of the package. θ_ja numbers are located in Table 2-4.
P = Power dissipation
Package Thermal Characteristics
The device junction-to-case thermal resistivity is θ_jc and the junction-to-ambient air thermal
resistivity is θ_ja. The thermal characteristics for θ_ja are shown for two air flow rates. The
recommended maximum junction temperature is 125°C. EQ 2-2 shows a sample calculation of the
recommended maximum power dissipation allowed for a 484-pin FBGA package at military
temperature and in still air.
Maximum Power Allowed = ^{M------a---x--.----j-u----n---c---t-i--o---n-----t--e---m-----p----.-----(--°}--C----)----^–----M-----a---x---.---a---m-----b----i-e---n---t----t--e---m-----p---.----(--^°--C-----) = ^{1----2---5----°}---C-----^–-----7---0----^°--C--- = 2.670
θ _{j a} ( ° C/W)
20.6°C/W
EQ 2-2
Table 2-4 • Package Thermal Resistivities
Package Type
Plastic Quad Flat Pack (PQ208)*
Device
A3P1000
θ_ja
Pin Count θ_jc Still Air 200 ft./min. 500 ft./min. Units
208 3.8 16.2
13.3
11.9
C/W
Fine Pitch Ball Grid Array (FBGA)
A3P1000
144 6.3 31.6
26.2
24.2
C/W
A3PE600L
484
9.5 27.5
21.9
20.2
C/W
A3PE3000L
484
4.7 20.6
15.7
14.0
C/W
A3PE3000L 896 2.4 13.6
10.4
9.4
C/W
* Embedded heatspreader
v1.0
2-7