Altera Cyclone II PowerPlay Early Power Estimator - Manual (Page 46)

3–30 Altera Corporation
PowerPlay Early Power Estimator User Guide For Cyclone II FPGAs May 2006
Power Analysis
Table 3–10 describes the thermal analysis parameters in the PowerPlay
Early Power Estimator spreadsheet.
Power Supply Sizing (A)
The Power Supply Sizing section provides the estimated current drawn
from power supplies. The I
CCINT
current is the supply current drawn from
V
CCINT
. The total I
CCIO
current is the supply current drawn from V
CCIO
power supplies. For estimates of I
CCIO
based on I/O banks, refer to the I/O
section of the PowerPlay Early Power Estimator spreadsheet.
Figure 3–27 shows the power supply sizing estimation. I
CCINT
and total
I
CCIO
are displayed.
Figure 3–27. Power Supply Sizing in the PowerPlay Early Power Estimator
Spreadsheet
Table 3–10. Thermal Analysis Section Information
Column Heading Description
Junction Temp, T
J
(°C) This shows the device junction temperature estimated based on supplied thermal
parameters.
The junction temperature is determined by dissipating the total thermal power through
the top of the chip and through the board (if selected). See Details for detailed
calculations used.
θ
J A
Junction-Ambient This shows the junction-to-ambient thermal resistance between the device and
ambient air, in °C/W.
This represents the increase in temperature between ambient and junction for every
Watt of additional power dissipation.
θ
J B
Junction-Board This shows the junction-to-board thermal resistance, in °C/W. This is used in
conjunction with the board temperature, as well as the top-of-chip
θ
J A
and ambient
temperatures, to compute junction temperature.
Maximum Allowed T
A
(°C)
This shows a guideline for the maximum ambient temperature (in °C) that the device
can be subjected to without violating maximum junction temperature, based on the
supplied cooling solution and device temperature grade.