6–66
Altera Corporation
Stratix GX Device Handbook, Volume 1
June 2006
High-Speed I/O Specification
tLSKEW
Clock skew between two external clock
outputs driven by the same counter
±50
ps
tSKEW
Clock skew between two external clock
outputs driven by the different counters
with the same settings
±75
ps
fSS
Spread spectrum modulation frequency
30
150
kHz
% spread
Percentage spread for spread
0.5
0.6
%
tARESET
Minimum pulse width on areset
signal
10
ns
(1)
The minimum input clock frequency to the PFD (fIN/N) must be at least 3 MHz for Stratix device enhanced PLLs.
(2)
(3)
tFCOMP can also equal 50% of the input clock period multiplied by the pre-scale divider n (whichever is less).
(4)
This parameter is timing analyzed by the Quartus II software because the scanclk and scandata ports can be
driven by the logic array.
(5)
Actual jitter performance may vary based on the system configuration.
(6)
Total required time to reconfigure and lock is equal to tDLOCK + tCONFIG. If only post-scale counters and delays are
changed, then tDLOCK is equal to 0.
(7)
The VCO range is limited to 500 to 800 MHz when the spread spectrum feature is selected.
(8)
Lock time is a function of PLL configuration and may be significantly faster depending on bandwidth settings or
feedback counter change increment.
(9)
Exact, user-controllable value depends on the PLL settings.
(10) The LOCK circuit on Stratix PLLs does not work for industrial devices below -20C unless the PFD frequency > 200
MHz. See the Stratix FPGA Errata Sheet for more information on the PLL.
Table 6–90. Enhanced PLL Specifications for -7 Speed Grade (Part 3 of 3)
Symbol
Parameter
Min
Typ
Max
Unit