
Spartan-3 FPGA Family: DC and Switching Characteristics
DS099 (v3.1) June 27, 2013
Product Specification
92
Clock Distribution Switching Characteristics
Table 56: Block RAM Timing
Symbol
Description
Speed Grade
Units
-5
-4
Min
Max
Min
Max
Clock-to-Output Times
TBCKO
When reading from the Block RAM,
the time from the active transition at
the CLK input to data appearing at
the DOUT output
–
2.09
–2.40
ns
Setup Times
TBDCK
Time from the setup of data at the
DIN inputs to the active transition at
the CLK input of the Block RAM
0.43
–0.49
–ns
Hold Times
TBCKD
Time from the active transition at the
Block RAM’s CLK input to the point
where data is last held at the DIN
inputs
0
–0
–ns
Clock Timing
TBPWH
Block RAM CLK signal High pulse
width
1.19
∞
1.37
∞
ns
TBPWL
Block RAM CLK signal Low pulse
width
1.19
∞
1.37
∞
ns
Notes:
1.
The numbers in this table are based on the operating conditions set forth in
Table 32.
2.
For minimums, use the values reported by the Xilinx timing analyzer.
Table 57: Clock Distribution Switching Characteristics
Description
Symbol
Maximum
Units
Speed Grade
-5
-4
Global clock buffer (BUFG, BUFGMUX, BUFGCE) I-input to O-output delay
TGIO
0.36
0.41
ns
Global clock multiplexer (BUFGMUX) select S-input setup to I0- and I1-inputs. Same
as BUFGCE enable CE-input
TGSI
0.53
0.60
ns
Notes:
1.
For minimums, use the values reported by the Xilinx timing analyzer.