XC3S100E_06 Datasheet, PDF (146/231 Pages) Xilinx, Inc – Configurable Logic Block (CLB)

R
DC and Switching Characteristics
Digital Frequency Synthesizer (DFS)
Table 105: Recommended Operating Conditions for the DFS
Symbol
Input Frequency Ranges⁽²⁾
F_CLKIN CLKIN_FREQ_FX
Input Clock Jitter Tolerance⁽³⁾
CLKIN_CYC_JITT_FX_LF
CLKIN_CYC_JITT_FX_HF
CLKIN_PER_JITT_FX
Description
Frequency for the CLKIN input
Cycle-to-cycle jitter at the
CLKIN input, based on CLKFX
output frequency
Period jitter at the CLKIN input
F_CLKFX < 150 MHz
F_CLKFX > 150 MHz
Speed Grade
-5
-4
Min Max Min Max
0.200 333 0.200 333
-
±300
-
±300
-
±150
-
±150
-
±1
-
±1
Units
MHz
ps
ps
ns
Notes:
1. DFS specifications apply when either of the DFS outputs (CLKFX or CLKFX180) are used.
2. If both DFS and DLL outputs are used on the same DCM, follow the more restrictive CLKIN_FREQ_DLL specifications in Table 103.
3. CLKIN input jitter beyond these limits may cause the DCM to lose lock.
Table 106: Switching Characteristics for the DFS
Symbol
Output Frequency Ranges
CLKOUT_FREQ_FX_LF
CLKOUT_FREQ_FX_HF
CLKOUT_FREQ_FX
Output Clock Jitter^(2,3)
CLKOUT_PER_JITT_FX
CLKOUT_PER_JITT_FX_35
(T_J35)
Description
Device
Frequency for the CLKFX and
CLKFX180 outputs, low frequencies
Frequency for the CLKFX and
CLKFX180 outputs, high frequencies
Frequency for the CLKFX and
CLKFX180 outputs
Stepping 0
Stepping 0
Stepping 1
XC3S100E
XC3S250E
XC3S500E
XC3S1600E
XC3S1200E
All
Period jitter at the CLKFX and CLKFX180 outputs
All
Period jitter at the CLKFX and CLKFX180 outputs when All in FG or CP
CLKFX_MULTIPLY=7, CLKFX_DIVIDE=2
packages
Duty Cycle^(4,5)
CLKOUT_DUTY_CYCLE_FX Duty cycle precision for the CLKFX and CLKFX180
All
outputs, including the BUFGMUX and clock tree
duty-cycle distortion
Phase Alignment⁽⁵⁾
CLKOUT_PHASE_FX
Phase offset between the DFS CLKFX output and the
All
DLL CLK0 output when both the DFS and DLL are used
CLKOUT_PHASE_FX180
Phase offset between the DFS CLKFX180 output and
All
the DLL CLK0 output when both the DFS and DLL are
used
Speed Grade
-5
-4
Min Max Min Max
Units
5
90
5
90 MHz
220 326 220 307 MHz
5
307
5
307 MHz
333
311 MHz
See Note 4 below
ps
±[2% of
CLKFX
period
+ 400]
±[2% of ps
CLKFX
period
+ 400]
- ±[1% of - ±[1% of ps
CLKFX
CLKFX
period
period
+ 400]
+ 400]
-
±200
-
±200 ps
- ±[1% of - ±[1% of ps
CLKFX
CLKFX
period
period
+ 300]
+ 300]
146
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DS312-3 (v3.4) November 9, 2006
Product Specification