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DC and Switching Characteristics
20 www.xilinx.com DS610-3 (v2.0) July 16, 2007
Product Specification
R
Switching Characteristics
All Spartan-3A DSP FPGAs ship in two speed grades: –4
and the higher performance –5. Switching characteristics in
this document are designated as Preview, Advance,
Preliminary, or Production, as shown in Table 15 . Each
category is defined as follows:
Preview: These specifications are based on estimates only
and should not be used for timing analysis.
Advance: These specifications are based on simulations
only and are typically available soon after establishing
FPGA specifications. Although speed grades with this
designation are considered relatively stable and
conservative, some under-reporting might still occur.
Preliminary: These specifications are based on complete
early silicon characterization. Devices and speed grades
with this designation are intended to give a better indication
of the expected performance of production silicon. The
probability of under-reporting preliminary delays is greatly
reduced compared to Advance data.
Production: These specifications are approved once
enough production silicon of a particular device family
member has been characterized to provide full correlation
between speed files and devices over numerous production
lots. There is no under-reporting of delays, and customers
receive formal notification of any subsequent changes.
Typically, the slowest speed grades transition to Production
before faster speed grades.
Software Version Requirements
Production-quality systems must use FPGA designs
compiled using a speed file designated as PRODUCTION
status. FPGAs designs using a less mature speed file
designation should only be used during system prototyping
or pre-production qualification. FPGA designs with speed
files designated as Preview, Advance, or Preliminary should
not be used in a production-quality system.
Whenever a speed file designation changes, as a device
matures toward Production status, rerun the latest Xilinx
ISE™ software on the FPGA design to ensure that the
FPGA design incorporates the latest timing information and
software updates.
Production designs will require updating the Xilinx ISE
development software with a future version and/or Service
Pack.
All parameter limits are representative of worst-case supply
voltage and junction temperature conditions. Unless
otherwise noted, the published parameter values apply
to all Spartan-3A DSP devices. AC and DC
characteristics are specified using the same numbers
for both commercial and industrial grades.