Pinout Descriptions
Package Thermal Characteristics
The power dissipated by an FPGA application has
The junction-to-case thermal resistance (θJC) 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 (θJB)
value similarly reports the difference between the board and
junction temperature. The junction-to-ambient (θJA) value
reports the temperature difference between the ambient
environment and the junction temperature. The θJA value is
reported at different air velocities, measured in linear feet
per minute (LFM). The “Still Air (0 LFM)” column shows the
implications on package selection and system design. The
power consumed by a Spartan-3A 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 FPGA package offerings. This
information is also available using the Thermal Query tool
on xilinx.com (www.xilinx.com/cgi-bin/thermal/thermal.pl).
θ
JA value in a system without a fan. The thermal resistance
drops with increasing air flow.
Table 62: Spartan-3A Package Thermal Characteristics
Junction-to-Ambient (θ
)
JA
at Different Air Flows
Junction-to-Case
(θ
Junction-to-
Still Air
(0 LFM)
Package
Device
XC3S50A
XC3S200A
)
Board (θ
)
JB
250 LFM
40.4
500 LFM
37.6
750 LFM
36.6
Units
°C/Watt
°C/Watt
JC
12.9
10.9
30.1
48.5
42.9
VQ100
VQG100
25.7
35.7
33.2
32.4
TQ144
TQG144
XC3S50A
16.5
32.0
42.4
36.3
35.8
34.9
°C/Watt
XC3S50A
XC3S200A
XC3S400A
XC3S700A
XC3S1400A
XC3S200A
XC3S400A
XC3S400A
XC3S700A
XC3S700A
XC3S1400A
16.0
10.3
8.4
33.5
23.8
19.3
18.6
14.1
18.5
15.4
15.5
13.0
12.8
9.9
42.3
32.7
29.9
28.1
24.2
27.8
25.2
25.6
23.1
22.3
19.5
35.6
26.6
24.9
22.3
18.7
22.3
19.8
19.2
17.9
17.4
14.7
35.5
26.1
23.0
21.2
17.5
21.1
18.6
18.0
16.7
16.2
13.5
34.5
25.2
22.3
20.7
17.0
20.3
17.8
17.3
16.0
15.5
12.8
°C/Watt
°C/Watt
°C/Watt
°C/Watt
°C/Watt
°C/Watt
°C/Watt
°C/Watt
°C/Watt
°C/Watt
°C/Watt
FT256
FTG256
7.8
5.4
11.7
9.9
FG320
FGG320
9.8
FG400
FGG400
8.2
7.9
FG484
FGG484
6.0
FG676
FGG676
XC3S1400A
5.8
9.4
17.8
13.5
12.4
11.8
°C/Watt
DS529-4 (v2.0) August 19, 2010
www.xilinx.com
69
XILINX [ XILINX, INC ]
