a1240a-pg132b Actel Corporation, a1240a-pg132b Datasheet - Page 11

• Manufacturer Part Number: a1240a-pg132b
• Description: Hirel Fpgas
• Manufacturer: Actel Corporation

Pa c ka ge T he r m a l C ha r a ct e r i s t i c s
The device junction to case thermal characteristic is
the junction to ambient air characteristic is
characteristics for
rates.
Po w e r D i s s i pa t i o n
Gener al P ow er E quat i on
where:
I
are changing.
Accurate values for N and M are difficult to determine
because they depend on the family type, on the design, and on
the system I/O. The power can be divided into two
components—static and active.
S tat i c P ow er Co m ponen t
Actel FPGAs have small static power components that result
in power dissipation lower than that of PALs or PLDs. By
integrating multiple PALs or PLDs into one FPGA, an even
greater reduction in board-level power dissipation can be
achieved.
Package Type
Ceramic Pin Grid Array
Ceramic Quad Flat Pack
CC
standby is the current flowing when no inputs or outputs
P = [I
I
I
V
N equals the number of outputs driving TTL loads to
V
M equals the number of outputs driving TTL loads to
V
CC
OL
OL
OL
OH
active is the current flowing due to CMOS switching.
, I
, V
.
.
CC
OH
OH
standby + I
are TTL sink/source currents.
are TTL level output voltages.
I
OH
ja
are shown with two different air flow
* (V
CC
active] * V
CC
– V
Max. junction temp. (°C) – Max. military temp.
----------------------------------------------------------------------------------------------------------------- -
OH
) * M
CC
+ I
Pin Count
OL
132
133
176
207
257
132
172
196
256
84
84
ja
* V
. The thermal
OL
ja
(°C/W)
* N +
jc
, and
6.0
4.8
4.8
4.6
3.5
2.8
7.8
7.2
6.8
6.4
6.2
jc
Maximum junction temperature is 150°C.
A sample calculation of the absolute maximum power
dissipation allowed for a CPGA 176-pin package at military
temperature is as follows:
The power due to standby current is typically a small
component of the overall power. Standby power is calculated
below for commercial, worst-case conditions.
The static power dissipated by TTL loads depends on the
number of outputs driving high or low and the DC load
current. Again, this value is typically small. For instance, a
32-bit bus sinking 4 mA at 0.33V will generate 42 mW with all
outputs driving low, and 140 mW with all outputs driving high.
Ac ti ve P ower Com po nent
Power dissipation in CMOS devices is usually dominated by
the active (dynamic) power dissipation. This component is
frequency dependent, a function of the logic and the external
I/O. Active power dissipation results from charging internal
chip capacitances of the interconnect, unprogrammed
antifuses, module inputs, and module outputs, plus external
capacitance due to PC board traces and load device inputs.
An additional component of the active power dissipation is
the totempole current in CMOS transistor pairs. The net
effect can be associated with an equivalent capacitance that
1200XL/3200DX
Family
ACT 3
ACT 2
ACT 1
=
Still Air
150°C – 125°C
------------------------------------
33
25
25
23
21
15
40
35
25
23
20
23°C/W
ja
2 mA
2 mA
2 mA
3 mA
I
CC
=
300 ft/min
1.1 W
20
16
15
12
10
30
25
20
15
10
8
ja
5.25V
5.25V
5.25V
5.25V
V
CC
H iR e l F PG A s
Units
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
10.5 mW
10.5 mW
10.5 mW
15.8 mW
Power
11