Xilinx DS610 - Manual (Page 65)

Spartan-3A DSP FPGA Family: Pinout Descriptions
DS610 (v3.0) October 4, 2010 www.xilinx.com
Product Specification 65
Package Thermal Characteristics
The power dissipated by an FPGA application has implications on package selection and system design. The power
consumed by a Spartan-3A DSP FPGA is reported using either the
XPower Power Estimator or the XPower Analyzer
calculator integrated in the Xilinx ISE® development software. Table 62 provides the thermal characteristics for the various
Spartan-3A DSP device package offerings. This information is also available using the Thermal Query tool .
The junction-to-case thermal resistance (
θ
JC
) indicates the difference between the temperature measured on the package
body (case) and the die junction temperature per watt of power consumption. The junction-to-board (
θ
JB
) value similarly
reports the difference between the board and junction temperature. The junction-to-ambient (
θ
JA
) value reports the
temperature difference between the ambient environment and the junction temperature. The
θ
JA
value is reported at
different air velocities, measured in linear feet per minute (LFM). The “Still Air (0 LFM)” column shows the
θ
JA
value in a
system without a fan. The thermal resistance drops with increasing air flow.
Table 62: Spartan-3A DSP FPGA Package Thermal Characteristics
Package Device
Junction-to-Case
(
θ
JC
)
Junction-to-
Board (
θ
JB
)
Junction-to-Ambient (
θ
JA
)
at Different Air Flows
Units
Still Air
(0 LFM)
250 LFM 500 LFM 750 LFM
CS484
CSG484
XC3SD1800A 4.1 6.8 18.0 13.3 12.3 11.5 °C/W
XC3SD3400A 3.5 5.6 16.9 12.2 11.0 10.4 °C/W
FG676
FGG676
XC3SD1800A 4.7 7.8 15.9 11.6 10.6 10.0 °C/W
XC3SD3400A 3.8 6.4 14.7 10.5 9.4 8.9 °C/W