Xilinx DS610 manual Switching Characteristics, Software Version Requirements

DC and Switching Characteristics

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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.

20	www.xilinx.com	DS610-3 (v2.0) July 16, 2007
		Product Specification