EX256-CS100 ACTEL [Actel Corporation], EX256-CS100 Datasheet - Page 19

• Manufacturer Part Number: EX256-CS100
• Description: eX Automotive Family FPGAs
• Manufacturer: ACTEL [Actel Corporation]

Table 1-11
components of eX devices.
Table 1-11 • Capacitance of Clock Components of eX
The estimation of the dynamic power dissipation is a
piece-wise linear summation of the power dissipation of
each component.
Dynamic power dissipation
= V
fm
C
(r2 * fq2))
fs1))
where:
m
m
n
p
q1
q2
r1
r2
s1
C
C
C
C
C
C
C
C
fm
fm
Dedicated array clock –
variable (Ceqhv)
Dedicated array clock – fixed
(Ceqhf)
Routed array clock A (r1)
Routed array clock B (r2)
eqcr
eqcm
eqsm
eqi
eqcr
eqhv
eqhf
eqo
L
c
s
S
c
s
CCA
)
Seq Modules
HCLK
* fq1) + (r1 * fq1))
= Number of combinatorial cells switching at
= Number of sequential cells switching at
= Number
= Number of output buffers switching at
= Average R-cell switching frequency, typically
2
= Number of R-cells driven by routed array
= Number of R-cells driven by routed array
= Fixed capacitance due to routed array clock A
= Fixed capacitance due to routed array clock B
= Number of R-cells driven by dedicated array
= Equivalent
= Equivalent capacitance of sequential modules
= Equivalent capacitance of input buffers
= Equivalent capacitance of routed array clocks
= Variable capacitance of dedicated array clock
= Fixed capacitance of dedicated array clock
= Equivalent capacitance of output buffers
= Average output loading capacitance, typically
= Average C-cell switching frequency, typically
* [(m
] + V
frequency fm, typically 20% of C-cells
frequency fm, typically 20% of R-cells
frequency fn, typically number of inputs / 4
frequency fp, typically number of outputs / 4
clock A
clock B
clock
modules
10pF
F/10
F/10
RCLKB
Devices
shows
CCI
c
* C
+ (n * C
2
* [(p * (C
+ (0.5 * (s1 * C
eqcm
of
the
capacitance
* fm
eqi
RCLKA
input
eqo
* fn)
capacitance
C
)
18.00 pF 20.00 pF 25.00 pF
23.00 pF 28.00 pF 35.00 pF
23.00 pF 28.00 pF 35.00 pF
0.85 pF
Comb Modules
+ (0.5 * (q2 * C
+ C
eX64
buffers
Input Buffers
L
) * fp)
eqhv
of
eX128
0.85 pF
Output Buffers
combinatorial
switching
* fs1)+(C
of
+ (m
+ (0.5 * (q1 *
eqcr
the
s
* C
0.85 pF
eX256
* fq2) +
eqhf
eqsm
clock
]
at
*
*
v3.2
fn
fp
fq1
fq2
fs1
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.aspx.
Junction Temperature
The temperature variable in the Designer software refers
to
temperature. This is an important distinction because the
heat generated from dynamic power consumption is
usually hotter than the ambient temperature.
shown below, can be used to calculate junction
temperature. Please refer to
the recommended operating conditions.
Where:
T
∆T = Temperature gradient between junction (silicon)
and ambient = θ
P = Power
θ
located in the
on page
ja
a
= Ambient Temperature
= Junction to ambient of package.
the
= Average output buffer switching frequency,
= Average input buffer switching frequency,
= Frequency of routed clock A
= Frequency of routed clock B
= Frequency of dedicated array clock
1-16.
typically F/5
typically F/5
junction
Junction Temperature = ∆T + T
"Package Thermal Characteristics" section
ja
* P
temperature,
eX Automotive Family FPGAs
Table 1-9 on page 1-12
not
θ
a
ja
(1)
the
numbers are
ambient
EQ
EQ 1-1
1-1,
1-15
for