Altera PowerPlay Early Power Estimator - Manual (Page 61)

Altera Corporation 3–43
January 2007 PowerPlay Early Power Estimator For Stratix II, Stratix II GX & HardCopy II
Using the PowerPlay Early Power Estimator
Figure 3–30 shows the thermal analysis, including the junction
temperature (T
J
), total
θ
JA
,
θ
JB
, and the maximum allowed T
A
values. For
details on the values of the thermal parameters not listed, click the
Details…
button.
Figure 3–30. Thermal Analysis in the PowerPlay Early Power Estimator
Table 3–13 describes the thermal analysis parameters in the PowerPlay
Early Power Estimator.
Power Supply Current (A)
The power supply current provides the estimated current consumption
for power supplies. The I
CCINT
current is the supply current required from
V
CCINT
. The I
CCPD
current is the supply current required from V
CCPD
. The
total I
CCIO
current is the supply current required from V
CCIO
for all I/O
banks. For estimates of I
CCIO
based on I/O banks, refer to the I/O section
Table 3–13. 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.