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Altera Corporation
1–3
July 2005
Stratix Device Handbook, Volume 2
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–3 shows the enhanced and fast PLL features in Stratix and
Stratix GX devices.
Table 1–3. Stratix & Stratix GX PLL Features
Feature
Enhanced PLL
Fast PLL
Clock multiplication and division
m/(n
× post-scale counter)
(1)m/(post-scale counter)
(2)Phase shift
Down to 156.25-ps increments
(3),
(4)Down to 125-ps increments
(3),
(4)Clock switchover
v
PLL reconfiguration
v
Programmable bandwidth
v
Spread spectrum clocking
v
Programmable duty cycle
vv
Number of internal clock outputs
6
Number of external clock outputs
Four differential/eight singled-ended
Number of feedback clock inputs
(1)
For enhanced PLLs, m, n, range from 1 to 512 and post-scale counters g, l, e range from 1 to 1024 with 50% duty
cycle. With a non-50% duty cycle the post-scale counters g, l, e range from 1 to 512.
(2)
For fast PLLs, m, n, and post-scale counters range from 1 to 32.
(3)
The smallest phase shift is determined by the voltage controlled oscillator (VCO) period divided by 8.
(4)
For degree increments, Stratix and Stratix GX devices can shift all output frequencies in increments of at least 45
° .
Smaller degree increments are possible depending on the frequency and divide parameters.
(5)
PLLs 7, 8, 9, and 10 have two output ports per PLL. PLLs 1, 2, 3, and 4 have three output ports per PLL. On Stratix
GX devices, PLLs 3, 4, 9, and 10 are not available for general-purpose use.
(6)
Every Stratix and Stratix GX device has two enhanced PLLs (PLLs 5 and 6) with either eight single-ended outputs
or four differential outputs each. Two additional enhanced PLLs (PLLs 11 and 12) in EP1S80, EP1S60, EP1S40 (PLL
11 and 12 not supported for F780 package), and EP1SGX40 devices each have one single-ended output.
(7)
Fast PLLs can drive to any I/O pin as an external clock. For high-speed differential I/O pins, the device uses a data
channel to generate txclkout.
(8)
Every Stratix and Stratix GX device has two enhanced PLLs with one single-ended or differential external feedback
input per PLL.