Data Sheet
June 1999
ORCA Series 3C and 3T FPGAs
Package Thermal Characteristics (continued)
FPGA Maximum Junction Temperature
Once the power dissipated by the FPGA has been determined (see the Estimating Power Dissipation section), the
maximum junction temperature of the FPGA can be found. This is needed to determine if speed derating of the
device from the 85 °C junction temperature used in all of the delay tables is needed. Using the maximum ambient
temperature, TAmax, and the power dissipated by the device, Q (expressed in °C), the maximum junction tempera-
ture is approximated by:
TJmax = TAmax + (Q • ΘJA)
Table 76 lists the plastic package thermal characteristics for the ORCA Series FPGAs.
Table 76. Plastic Package Thermal Characteristics for the ORCA Series1
ΘJA (°C/W)
TA = 70 °C max
TJ = 125 °C max
@ 0 fpm (W)
Package
0 fpm
200 fpm
500 fpm
208-Pin SQFP1
208-Pin SQFP21
240-Pin SQFP1
240-Pin SQFP21
256-Pin PBGA1, 2
256-Pin PBGA1, 3
352-Pin PBGA1, 2
352-Pin PBGA1, 3
432-Pin EBGA1
600-Pin EBGA1
26.5
12.8
25.5
13.0
22.5
26.0
19.0
25.5
11.0
11.0
23.0
10.3
22.5
10.0
19.0
22.0
16.0
22.0
8.5
21.0
9.1
2.1
4.3
2.2
4.2
2.4
2.1
2.9
2.1
5.0
5.5
21.0
9.0
17.5
20.5
15.0
20.5
7.5
8.5
7.5
1. Mounted on 4-layer JEDEC standard test board with two power/ground planes.
2. With thermal balls connected to board ground plane.
3. Without thermal balls connected to board ground plane.
Lucent Technologies Inc.
195
AGERE [ AGERE SYSTEMS ]
