A42MX09-1TQG176M Microsemi, A42MX09-1TQG176M Datasheet - Page 17

• Manufacturer Part Number: A42MX09-1TQG176M
• Description: Ic Fpga Mx Sgl Chip 14k 176-Tqfp
• Manufacturer: Microsemi

Power Dissipation
General Power Equation
where:
Accurate values for N and M are difficult to determine
because they depend on the family type, on 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 power dissipation lower than PALs or CPLDs. By
integrating multiple PALs/CPLDs into one FPGA, an even
greater reduction in board-level power dissipation can
be achieved.
The power due to standby current is typically a small
component of the overall power.
The static power dissipation by TTL loads depends on the
number of outputs driving HIGH or LOW, and on 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.
I
outputs are changing.
I
switching.
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
CC
OL
OL
OL
OH
standby is the current flowing when no inputs or
active is the current flowing due to CMOS
P = [I
, I
, V
.
.
OH
OH
CC
are TTL sink/source currents.
are TTL level output voltages.
standby + I
+ I
OH
* (V
CC
active] * V
CCI
– V
OH
) * M
CCI
+ I
OL
* V
OL
* N
v3.1
Active Power Component
Power dissipation in CMOS devices is usually dominated
by
component is frequency-dependent and 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.
The power dissipated by a CMOS circuit can be expressed
by the equation:
where:
Equivalent Capacitance
Equivalent capacitance is calculated by measuring
I
circuit component of interest. Measurements have been
made over a range of frequencies at a fixed value of
Equivalent capacitance is frequency-independent, so the
results can be used over a wide range of operating
conditions. Equivalent capacitance values are shown on
the following page.
CC
C
V
F
EQ
CCA
active at a specified frequency and voltage for each
the
=
=
=
active
Equivalent
picofarads (pF)
Power supply in volts (V)
Switching frequency in megahertz (MHz)
40MX and 42MX Automotive FPGA Families
Power (µW) = C
(dynamic)
capacitance
EQ
power
* V
CCA
2
dissipation.
* F
expressed
EQ 1-1
1-13
V
This
CC
in
.