Cyclone™ devices support differential I/O standards, such as LVDS and reduced swing differential signaling (RSDS), as well as single-ended I/O standards, such as LVTTL, LVCMOS, SSTL, and PCI, commonly used for interfacing with other devices on the board.
Differential I/O Standards in Cyclone Devices
Cyclone devices provide support for LVDS and RSDS on up to 129 channels. Cyclone devices can interface with LVDS signals using differential LVDS buffers capable of data transfer rates as high as 640 megabits per second (Mbps). The LVDS buffers in Cyclone devices maintain signal integrity, provide low electromagnetic interference (EMI), and consume less power compared to single-ended I/O standards. Figure 1 shows the LVDS interface in Cyclone devices.
Figure 1. LVDS Interface in Cyclone Devices
Note to Figure 1:
-
The resistor network is external to the Cyclone device.
Table 1 lists the number of LVDS and RSDS data channels and performance available on Cyclone devices.
| Table 1. Number of LVDS Channels Per Cyclone Device | |||||
| Device | Package | LVDS Channels | Performance | RSDS Channels | Performance |
| EP1C3 | 144-pin TQFP (1) | 34 | 640 Mbps | 34 | 311 Mbps |
| EP1C4 | 324-pin FineLine BGA® | 103 | 640 Mbps | 103 | 311 Mbps |
| 400-pin FineLine BGA | 129 | 640 Mbps | 129 | 311 Mbps | |
| EP1C6 | 144-pin TQFP | 29 | 640 Mbps | 29 | 311 Mbps |
| 240-pin PQFP (2) | 72 | 640 Mbps | 72 | 311 Mbps | |
| EP1C12 | 240-pin PQFP | 66 | 640 Mbps | 66 | 311 Mbps |
| 324-pin FineLine BGA | 103 | 640 Mbps | 103 | 311 Mbps | |
| EP1C20 | 324-pin FineLine BGA | 95 | 640 Mbps | 95 | 311 Mbps |
| 400-pin FineLine BGA | 129 | 640 Mbps | 129 | 311 Mbps | |
- TQFP = thin quad flat pack
- PQFP = plastic quad flat pack
Single-Ended I/O Standards in Cyclone Devices
To interface with other devices on a board, Cyclone devices support single-ended I/O standards such as LVTTL, LVCMOS, SSTL-2, SSTL-3, and PCI. Single-ended I/O standards 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 FCRAM devices. Table 2 lists the single-ended I/O standards supported in Cyclone devices.
| Table 2. Cyclone Device Single-Ended I/O Standard Support | ||
| I/O Standard | Performance | Typical Application |
| 3.3-V/2.5-V/1.8-V LVTTL | 250 MHz | General Purpose |
| 3.3-V/2.5-V/1.8-V/1.5-V LVCMOS | 250 MHz | General Purpose |
| SSTL-3 Class I & II | 166 MHz | SDR SDRAM |
| SSTL-2 Class I & II | 133 MHz | DDR SDRAM & FCRAM |
| 3.3-V PCI | 66 MHz | PC & Embedded |
Related Links
