EX128-PTQG100 Datasheet, PDF (21/49 Pages) Actel Corporation – eX Family FPGAs

eX Family FPGAs
C_eqsm = Equivalent capacitance of sequential
modules
C_eqi = Equivalent capacitance of input buffers
C_eqcr = Equivalent capacitance of routed array clocks
C_eqhv = Variable capacitance of dedicated array clock
C_eqhf = Fixed capacitance of dedicated array clock
C_eqo = Equivalent capacitance of output buffers
C_L = Average output loading capacitance,
typically 10 pF
fm_c = Average C-cell switching frequency, typically
F/10
fm_s = Average R-cell switching frequency, typically
F/10
fn = Average input buffer switching frequency,
typically F/5
fp = Average output buffer switching frequency,
typically F/5
fq1 = Frequency of routed clock A
fq2 = Frequency of routed clock B
fs1 = Frequency of dedicated array clock
The eX, SX-A and RTSX-S Power Calculator can be used to
estimate the total power dissipation (static and dynamic)
of eX devices and can be found at
http://www.actel.com/products/rescenter/power/
calculators.asp.
Thermal Characteristics
The temperature variable in the Designer software refers
to the junction temperature, not the ambient
temperature. This is an important distinction because the
heat generated from dynamic power consumption is
usually hotter than the ambient temperature. EQ 1-1,
shown below, can be used to calculate junction
temperature.
EQ 1-1
Junction Temperature = ∆T + T_a(1)
Where:
T_a = Ambient Temperature
∆T = Temperature gradient between junction
(silicon) and ambient = θ_ja * P
P = Power
θ_ja = Junction to ambient of package. θ_ja numbers are
located in the "Package Thermal Characteristics" section
below.
Package Thermal Characteristics
The device junction-to-case thermal characteristic is θ_jc,
and the junction-to-ambient air characteristic is θ_ja. The
thermal characteristics for θ_ja are shown with two
different air flow rates. θ_jc is provided for reference.
The maximum junction temperature is 150°C.
The maximum power dissipation allowed for eX devices
is a function of θ_ja. A sample calculation of the absolute
maximum power dissipation allowed for a TQFP 100-pin
package at commercial temperature and still air is as
follows:
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----)-
θ_ja(°C/W)
=
1---5---0----°_---C-----–_{-----7---0---}°_---C--
33.5°C/W
=
2.39W
Package Type
Thin Quad Flat Pack (TQFP)
Thin Quad Flat Pack (TQFP)
Chip Scale Package (CSP)
Chip Scale Package (CSP)
Chip Scale Package (CSP)
Pin Count
64
θ_jc
12.0
100
14.0
49
128
180
Still Air
42.4
33.5
72.2
54.1
57.8
θ_ja
1.0 m/s
200 ft/min
36.3
27.4
59.5
44.6
47.6
2.5 m/s
500 ft/min
34.0
25.0
54.1
40.6
43.3
Units
°C/W
°C/W
°C/W
°C/W
°C/W
v4.3
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