Lattice Semiconductor
101
Data Sheet
December 2002
ORCA Series 3C and 3T FPGAs
Timing Characteristics
Description
To dene speed grades, the ORCA Series part number
designation (see Ordering Information) uses a single-
digit number to designate a speed grade. This number
is not related to any single ac parameter. Higher num-
bers indicate a faster set of timing parameters. The
actual speed sorting is based on testing the delay in a
path consisting of an input buffer, combinatorial delay
through all PLCs in a row, and an output buffer. Other
tests are then done to verify other delay parameters,
such as routing delays, setup times to FFs, etc.
The most accurate timing characteristics are reported
by the timing analyzer in the ORCA Foundry Develop-
ment System. A timing report provided by the develop-
ment system after layout divides path delays into logic
and routing delays. The timing analyzer can also pro-
vide logic delays prior to layout. While this allows rout-
ing budget estimates, there is wide variance in routing
delays associated with different layouts.
The logic timing parameters noted in the Electrical
Characteristics section of this data sheet are the same
as those in the design tools. In the PFU timing given in
concatenation of the PFU operating mode (as dened
in
Table 3) and the parameter type. The setup, hold,
and propagation delay parameters, dened below, are
designated in the symbol name by the SET, HLD, and
DEL characters, respectively.
The values given for the parameters are the same as
those used during production testing and speed bin-
ning of the devices. The junction temperature and sup-
ply voltage used to characterize the devices are listed
in the delay tables. Actual delays at nominal tempera-
ture and voltage for best-case processes can be much
better than the values given.
It should be noted that the junction temperature used in
the tables is generally 85 °C. The junction temperature
for the FPGA depends on the power dissipated by the
device, the package thermal characteristics (ΘJA), and
the ambient temperature, as calculated in the following
equation and as discussed further in the Package
Thermal Characteristics section:
TJmax = TAmax + (P ΘJA) °C
Note: The user must determine this junction tempera-
ture to see if the delays from ORCA Foundry
should be derated based on the following derat-
ing tables.
ply and junction temperature derating for OR3Cxx com-
mercial and industrial devices.
Table 40 provides the
same information for the OR3Txxx devices (both com-
mercial and industrial). The delay values in this data
sheet and reported by ORCA Foundry are shown as
1.00 in the tables. The method for determining the max-
imum junction temperature is dened in the Package
Thermal Characteristics section. Taken cumulatively,
the range of parameter values for best-case vs. worst-
case processing, supply voltage, and junction tempera-
ture can approach 3 to 1.
Table 38
.DeratingforCommercialDevices
(OR3Cxx)
Table 39
.DeratingforIndustrialDevices(OR3Cxx)
Table 40.
DeratingforCommercial/Industrial
Devices(OR3Txxx)
Note: The derating tables shown above are for a typical critical path
that contains 33% logic delay and 66% routing delay. Since the
routing delay derates at a higher rate than the logic delay, paths
with more than 66% routing delay will derate at a higher rate
than shown in the table. The approximate derating values vs.
temperature are 0.26% per °C for logic delay and 0.45% per °C
for routing delay. The approximate derating values vs. voltage
are 0.13% per mV for both logic and routing delays at 25 °C.
TJ
(°C)
PowerSupplyVoltage
4.75V
5.0V
5.25V
0
0.81
0.79
0.77
25
0.85
0.83
0.81
85
1.00
0.97
0.95
100
1.05
1.02
1.00
125
1.12
1.09
1.07
TJ
(°C)
PowerSupplyVoltage
4.5V
4.75V
5.0V
5.25V
5.5V
–40
0.71
0.70
0.68
0.66
0.65
0
0.80
0.78
0.76
0.74
0.73
25
0.84
0.82
0.80
0.78
0.77
85
1.00
0.97
0.94
0.93
0.91
100
1.05
1.01
0.99
0.97
0.95
125
1.12
1.09
1.06
1.04
1.02
TJ
(°C)
PowerSupplyVoltage
3.0V
3.3V
3.6V
–40
0.73
0.66
0.61
0
0.82
0.73
0.68
25
0.87
0.78
0.72
85
1.00
0.90
0.83
100
1.04
0.94
0.87
125
1.10
1.00
0.92