Stratix™ GX devices support a variety of single-ended I/O standards, and easily interface with host processors, buses, memory devices, and 3D graphics controllers. Single-ended systems provide more current drive capacity than differential I/O standards, and they are critical when working with advanced memory devices such as double data rate (DDR) SDRAM and zero-bus turnaround (ZBT) SRAM devices. Table 1 lists the different single-ended I/O standards that are supported in Stratix GX devices as well as their typical applications.
| Table 1. Stratix GX Device Single-Ended I/O Standard Support | |||
| I/O Standard | Performance Target | Typical Application | |
| 3.3-V/2.5-V/1.8-V LVTTL | 250 MHz | General-purpose, ZBT SRAM | |
| 3.3-V/2.5-V/1.8-V/1.5-V LVCMOS | 250 MHz | General-purpose | |
| 3.3-V/2.5-V GTL | 100 MHz | Backplane | |
| 3.3-V/2.5-V GTL+ | 200 MHz | Backplane | |
| SSTL-3 Class I & II | 166 MHz | SDRAM | |
| SSTL-2 Class I & II | 200 MHz | DDR SDRAM | |
| 1.5-V HSTL I & II | 250 MHz | Memory & switch fabric | |
| 3.3-V PCI | 66 MHz | PC & embedded | |
| 3.3-V PCI-X | 133 MHz | PC & embedded | |
| Compact PCI | 60 MHz | PC & embedded | |
| 3.3-V/1.5-V 1x AGP | 60 MHz | 3-D graphics | |
| 3.3-V/1.5-V 2x AGP | 133 MHz | 3-D graphics | |
| CTT | 250 MHz | Backplane | |
