Integrator Series FPGAs: 1200XL and 3200DX Families
Package Thermal Characteristics
Maximum junction temperature is 150°C.
The device junction to case thermal characteristic is θjc,
and the junction to ambient air characteristic is θja. The
thermal characteristics for θja are shown with two different
air flow rates.
A sample calculation of the absolute maximum power
dissipation allowed for a PQFP 160-pin package with still air
at commercial temperature is as follows:
Max. junction temp. (°C) – Max. commercial temp.
150°C – 70°C
---------------------------------------------------------------------------------------------------------------------------- = --------------------------------- = 2 . 4 W
θja (°C/W)
34°C/W
θ
Maximum Power Dissipation
ja
Pin Count
Package Type
Still Air
300 ft/min
Still Air
300 ft/min
Plastic Quad Flat Pack
Plastic Quad Flat Pack
Plastic Quad Flat Pack
Plastic Quad Flat Pack
Plastic Leaded Chip Carrier
Thin Quad Flat Pack
100
144
160
208
84
42°C/W
36°C/W
34°C/W
25°C/W
37°C/W
32°C/W
16.8°C/W
16.1°C/W
43°C/W
33°C/W
29°C/W
27°C/W
16.2°C/W
28°C/W
25°C/W
11.4°C/W
10.6°C/W
35°C/W
1.9 W
2.2 W
2.4 W
3.2 W
2.2 W
2.5 W
4.8 W
5.0 W
1.9 W
2.4 W
2.8 W
3.0 W
4.9 W
2.9 W
3.2 W
7.0 W
7.5 W
2.3 W
176
208
240
100
Power Quad Flat Pack
Power Quad Flat Pack
Very Thin Quad Flat Pack
Power Dissipation
The power dissipation due to standby current is typically a
small component of the overall power. Standby power is
calculated below for commercial worst case conditions.
General Power Equation
P = [ICCstandby + ICCactive] * VCC + IOL* VOL* N
+ IOH * (VCC – VOH) * M
ICC
VCC
Power
2 mA
5.25 V
10.5 mW
where:
The static power dissipation by TTL loads depends on the
number of outputs driving HIGH or LOW and the DC load
current. Again, this number 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. The actual dissipation will average somewhere in
between as I/Os switch states with time.
ICCstandby is the current flowing when no inputs or
outputs are changing.
ICCactive is the current flowing due to CMOS switching.
IOL, IOH are TTL sink/source currents.
VOL, VOH are TTL level output voltages.
N equals the number of outputs driving TTL loads to VOL
.
Active Power Component
M equals the number of outputs driving TTL loads to VOH
.
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 totem pole current in the
CMOS transistor pairs. The net effect can be associated with
an equivalent capacitance that can be combined with
frequency and voltage to represent active power dissipation.
An accurate determination of N and M is problematic
because their values depend on the family type, design
details, and on the system I/O. The power can be divided
into two components: static and active.
Static Power Component
Actel FPGAs have small static power components that
result in lower power dissipation than PALs or PLDs. By
integrating multiple PALs/PLDs into one FPGA, an even
greater reduction in board-level power dissipation can
be achieved.
14
Discontinued – v3.0
ACTEL [ Actel Corporation ]
