EX128-CS100A datasheet(19/44 Pages) ACTEL

19 / 44 page

eX Automotive Family FPGAs

v3.2

1-15

Table 1-11

shows

the

capacitance

the

clock

components of eX devices.

The estimation of the dynamic power dissipation is a

piece-wise linear summation of the power dissipation of

each component.

Dynamic power dissipation

= VCCA

2 * [(m

c * Ceqcm * fmC)Comb Modules + (ms * Ceqsm *

fmS)Seq Modules + (n * Ceqi * fn)Input Buffers + (0.5 * (q1 *

Ceqcr * fq1) + (r1 * fq1))RCLKA + (0.5 * (q2 * Ceqcr * fq2) +

(r2 * fq2))RCLKB + (0.5 * (s1 * Ceqhv * fs1)+(Ceqhf *

fs1))HCLK] + VCCI

2 * [(p * (C

eqo + CL) * fp)Output Buffers]

where:

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

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. Please refer to Table 1-9 on page 1-12 for

the recommended operating conditions.

EQ 1-1

Junction Temperature =

∆T + T

a(1)

Where:

Ta = Ambient Temperature

∆T = Temperature gradient between junction (silicon)

and ambient =

ja * P

P = Power

ja = Junction to ambient of package. θja numbers are

located in the "Package Thermal Characteristics" section

on page 1-16.

Table 1-11 • Capacitance of Clock Components of eX

Devices

eX64

eX128

eX256

Dedicated array clock –

variable (Ceqhv)

0.85 pF

Dedicated array clock – fixed

(Ceqhf)

18.00 pF

20.00 pF

25.00 pF

Routed array clock A (r1)

23.00 pF

28.00 pF

35.00 pF

Routed array clock B (r2)

23.00 pF

28.00 pF

35.00 pF

= Number of combinatorial cells switching at

frequency fm, typically 20% of C-cells

= Number of sequential cells switching at

frequency fm, typically 20% of R-cells

= Number

input

buffers

switching

frequency fn, typically number of inputs / 4

= Number of output buffers switching at

frequency fp, typically number of outputs / 4

= Number of R-cells driven by routed array

clock A

= Number of R-cells driven by routed array

clock B

= Fixed capacitance due to routed array clock A

= Fixed capacitance due to routed array clock B

= Number of R-cells driven by dedicated array

clock

Ceqcm = Equivalent capacitance of combinatorial

modules

Ceqsm = Equivalent capacitance of sequential modules

Ceqi

= Equivalent capacitance of input buffers

Ceqcr = Equivalent capacitance of routed array clocks

Ceqhv = Variable capacitance of dedicated array clock

Ceqhf = Fixed capacitance of dedicated array clock

Ceqo

= Equivalent capacitance of output buffers

= Average output loading capacitance, typically

10pF

fmc

= Average C-cell switching frequency, typically

F/10

fms

= Average R-cell switching frequency, typically

F/10

= Average input buffer switching frequency,

typically F/5

= 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

EX128-CS100A Datasheet(PDF) 19 Page - Actel Corporation

EX128-CS100A Datasheet(HTML) 19 Page - Actel Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

Datasheet Download

Link URL