【应用手册】General-Purpose PLLs in Stratix & Stratix GX Devices Stratix® and Stratix GX devices have highly versatile phase-locked loops (PLLs) that provide robust clock management and synthesis for on-chip clock management, external system clock management, and high-speed I/O interfaces. There are two types of PLLs in each Stratix and Stratix GX device: enhanced PLLs and fast PLLs. Each device has up to four enhanced PLLs, which are feature-rich, general-purpose PLLs supporting advanced capabilities such as external feedback, clock switchover, phase and delay control, PLL reconfiguration, spread spectrum clocking, and programmable bandwidth. There are also up to eight fast PLLs per device, which offer general-purpose clock management with multiplication and phase shifting as well as high-speed outputs to manage the high-speed differential I/O interfaces. The Altera® Quartus® II software enables the PLLs and their features without requiring any external devices. 1. General-Purpose PLLs in Stratix & Stratix GX Devices S52001-3.2 Introduction Stratix and Stratix GX devices have highly versatile phase-locked loops (PLLs) that provide robust clock management and synthesis for on-chip clock management, external system clock management, and high-speed I/O interfaces. There are two types of PLLs in each Stratix and Stratix GX device: enhanced PLLs and fast PLLs. Each device has up to four enhanced PLLs, which are feature-rich, general-purpose PLLs supporting ……