R
XC4000E and XC4000X Series Field Programmable Gate Arrays
6-96 May 14, 1999 (Version 1.6)
XC4000EX Pin-to-Pin Input Parameter Guidelines
Testing of switching parameters is modeled after testing methods specified by MIL-M-38510/605. All devices are 100%
functionally tested. Pin-to-pin timing parameters are derived from measuring external and internal test patterns and are
guaranteed over worst-case operating conditions (supply voltage and junction temperature). Listed below are representative
values for typical pin locations and normal clock loading. For more specific, more precise, and worst-case guaranteed data,
reflecting the actual routing structure, use the values provided by the static timing analyzer (TRCE in the Xilinx Development
System) and back-annotated to the simulation netlist. These path delays, provided as a guideline, have been extracted from
the static timing analyzer report. Values apply to all XC4000EX devices unless otherwise noted
Global Low Skew Clock, Set-Up and Hold Guidelines
Global Early Clock, Set-Up and Hold for IF Guidelines
Global Early Clock, Set-Up and Hold for FCL Guidelines
Input Threshold Adjustments
The following table must be used to adjust input parameters and input switching characteristics.
Speed Grade -4 -3 -2 Units
Description Symbol Device Min Min Min
Input Setup Time, using Global Low Skew clock and
IFF (full delay) TPSD XC4028EX
XC4036EX 8.0
8.0 6.8
6.8 6.8
6.8 ns
ns
InputHoldTime,using Global Low Skew clock and IFF
(full delay) TPHD XC4028EX
XC4036EX 0
00
00
0ns
ns
IFF = Input Flip-Flop or Latch
Speed Grade -4 -3 -2 Units
Description Symbol Device Min Min Min
Input Setup Time, using Global Early clock and IFF
(partial delay) TPSEP XC4028EX
XC4036EX 6.5
6.5 5.4
5.4 5.4
5.4 ns
ns
Input Hold Time, using Global Early clock and IFF (par-
tial delay) TPHEP XC4028EX
XC4036EX 0
00
00
0ns
ns
IFF = Input Flip-Flop or Latch
Note: Set-up parameters are for BUFGE #s 3, 4, 7 and 8. Add 1.6 ns for BUFGE #s 1, 2, 5 and 6.
Speed Grade -4 -3 -2 Units
Description Symbol Device Min Min Min
Input Setup Time, using Global Early clock and
FCL (partial delay) TPFSEP XC4028EX
XC4036EX 3.4
4.4 3.4
4.2 3.4
4.2 ns
ns
Input Hold Time, using Global Early clock and
FCL (partial delay) TPFHEP XC4028EX
XC4036EX 0
00
00
0ns
ns
FCL = Fast Capture Latch
Notes: For CMOS input levels, see the “Input Threshold Adjustments” on page 96.
Setup time is measured with the fastest route and the lightest load. Use the static timing analyzer to determine the setup time
under given design conditions.
Hold time is measured using the farthest distance and a reference load of one clock pin per two IOBs. Use the static timing
analyzer to determine the setup and hold times under given design conditions.
Set-up parameters are for BUFGE #s 3, 4, 7 and 8. Add 1.2 ns for BUFGE #s 1, 2, 5 and 6.
Speed Grade -4 -3 -2 Units
Description Symbol Device Max Max Max
For TTL input add TTTLI All Devices 0 0 0 ns
For CMOS input add TCMOSI All Devices 0.3 0.2 0.2 ns