The phase-locked loop (PLL) block is a feedback control system that automatically adjusts the phase of a locally generated signal to match the phase of an input signal. PLLs operate by producing an oscillator frequency to match the frequency of an input signal. In this locked condition, any slight change in the input signal first appears as a change in phase between the input signal and the oscillator frequency. This phase shift then acts as an error signal to change the frequency of the local PLL oscillator to match the input signal. The locking-onto-a-phase relationship between the input signal and the local oscillator accounts for the name phase-locked loop. PLLs are often used in high-speed communication applications.
The following types of specialized PLLs are supported by Altera devices:
|
PLL Type |
Device Family Support |
|---|---|
|
ClockLock PLL |
ACEX 1K, APEX 20K, APEX II, and FLEX 10K device families |
|
Cyclone PLL |
Cyclone devices only |
|
Cyclone II PLL |
Cyclone II devices only |
|
enhanced PLL |
HardCopy Stratix, Stratix, Stratix II, Stratix II GX, Stratix III, Stratix IV, and Stratix GX device families |
|
fast PLL |
HardCopy Stratix, Stratix, Stratix II GX, Stratix III, Stratix IV, and Stratix GX device families |
|
GXB receiver PLL and GXB transmitter PLL |
Arria GX, Stratix II GX, Stratix IV GX, and Stratix GX devices |
|
left/right PLL |
Stratix III and Stratix IV device families only |
|
LVDS PLL |
APEX 20KC, APEX 20KE, and APEX II device families |
|
top/bottom PLL |
Stratix III and Stratix IV device families only |
|
PLL Type |
Device Family Support |
|---|---|
|
ClockLock PLL |
ACEX 1K, APEX 20K, APEX II, and FLEX 10K device families |
|
Cyclone PLL |
Cyclone devices only |
|
Cyclone II PLL |
Cyclone II devices only |
|
enhanced PLL |
HardCopy Stratix, Stratix, Stratix II, Stratix II GX, Stratix III, Stratix IV, and Stratix GX device families |
|
fast PLL |
HardCopy Stratix, Stratix, Stratix II GX, Stratix III, Stratix IV, and Stratix GX device families |
|
GXB receiver PLL and GXB transmitter PLL |
Arria GX, Stratix II GX, Stratix IV GX, and Stratix GX devices |
|
left/right PLL |
Stratix III and Stratix IV device families only |
|
LVDS PLL |
APEX 20KC, APEX 20KE, and APEX II device families |
|
top/bottom PLL |
Stratix III and Stratix IV device families only |
