PLLs in Stratix II and Stratix II GX Devices
Table 1–7. Stratix II and Stratix II GX Enhanced PLL Pins (Part 3 of 3)
Note (1)
Pin
Description
VCC_PLL12_OUT
External clock output VCCIO power for PLL12_OUT0p, PLL12_OUT0n,
PLL12_OUT1p, PLL12_OUT1nand PLL12_OUT2p, PLL12_OUT2noutputs
from PLL 12.
Note to Table 1–7:
(1) The negative leg pins (CLKn, PLL_FBn, and PLL_OUTn) are only required with differential signaling.
Stratix II devices contain up to eight fast PLLs and Stratix II GX devices
contain up to four fast PLLs. Fast PLLs have high-speed differential I/O
interface capability along with general-purpose features.
Fast PLLs
Fast PLL Hardware Overview
Figure 1–7 shows a diagram of the fast PLL.
Figure 1–7. Stratix II and Stratix II GX Fast PLL Block Diagram
Post-Scale
Counters
VCO Phase Selection
Selectable at each PLL
Output Port
Clock (1)
Switchover
Circuitry
Phase
Frequency
Detector
diffioclk0 (3)
loaden0 (4)
Global or
regional clock (2)
÷c0
÷c1
÷c2
diffioclk1 (3)
loaden1 (4)
(5)
8
Charge
Pump
Loop
Filter
÷k
÷n
PFD
VCO
4
Clock
Input
4
8
Global clocks
4
Global or
regional clock (2)
Regional clocks
÷c3
÷m
8
Shaded Portions of the
PLL are Reconfigurable
to DPA block
Notes to Figure 1–7:
(1) Stratix II and Stratix II GX fast PLLs only support manual clock switchover.
(2) The global or regional clock input can be driven by an output from another PLL, a pin-driven dedicated global or
regional clock, or through a clock control block provided the clock control block is fed by an output from another
PLL or a pin-driven dedicated global or regional clock. An internally generated global signal cannot drive the PLL.
(3) In high-speed differential I/O support mode, this high-speed PLL clock feeds the SERDES. Stratix II devices only
support one rate of data transfer per fast PLL in high-speed differential I/O support mode.
(4) This signal is a high-speed differential I/O support SERDES control signal.
(5) If the design enables this ÷2 counter, then the device can use a VCO frequency range of 150 to 520 MHz.
Altera Corporation
July 2009
1–15
Stratix II Device Handbook, Volume 2
ALTERA [ ALTERA CORPORATION ]
