APEX devices offer low-voltage differential signaling (LVDS) I/O interface circuitry. The LVDS interface provides:
- Data transfer rates up to 840 megabits per second (Mbps)
- Device bandwidth up to 256 gigabits per second (Gbps)
- Minimal power consumption
With LVDS, APEX devices offer the highest performance, highest bandwidth, system-on-a-programmable-chip solution for high-speed data transmission designs.
APEX 20KE Programmable I/O Blocks
APEX 20KE devices have eight programmable I/O blocks. Figure 1 shows that the eight I/O blocks support standards such as LVTTL, LVCMOS, 3.3-V PCI, GTL+, SSTL-2 and SSTL-3 Class I and II, CTT, and AGP(1); two of the blocks are capable of supporting LVDS. The LVDS blocks can be used as input, output, or bi-directional pins for the other I/O standards when they are not used for LVDS support.
Figure 1. APEX 20KE I/O Blocks
LVDS: The Backplane Interface Technology Leader
LVDS is a data interface standard that achieves higher data transfer rates than other I/O standards, has the lowest power consumption, and also minimizes electromagnetic interference (EMI) emission. Table 1 compares common backplane interface technologies.
| Table 1. Backplane Interface Technology Comparison | |||||
| Technology | APEX LVDS | ECL | BTL | GTL+ | High-Speed TTL |
|---|---|---|---|---|---|
| Power Consumption | Low | High | Medium | Medium | Medium |
| Speed (Mbps) | 622 | 200 | Up to 100 | Up to 100 | Up to 80 |
| Noise Immunity | High | Medium | Medium | Medium | Low |
| Hot insertion | Yes | Yes | Yes | Yes | Yes |
LVDS is a general-purpose interface that can be used in many different applications:
- Telecom/Datacom
- Switches
- Hubs
- Routers
- Computing
- Digital copiers
- Processor interface
- Imaging displays
- Audio and video digital signal processing
- MPEG stream processing
The APEX 20KE LVDS Advantage
APEX 20KE devices with LVDS capability provide numerous benefits, including:
- High-frequency performance up to 840 Mbps per channel
- Low power dissipation
- Dedicated built-in LVDS circuitry
- 16 input and output channels
- Built-in data skew reduction circuitry
- Support for 1x, 4x, 7x, or 8x serializer and deserializer
- Low ratio of chip power and ground pins to I/O pins
- Support interfaces for multi-drop and point-to-point backplane architecture
- Support data transfer across cable and connectors
When high-bandwidth communication is required, APEX 20KE devices with LVDS provide the robust, high-speed and low-power solution.
- LVTTL: low-voltage transistor-transistor logic; LVCMOS: low-voltage complementary metal-oxide semiconductor; PCI: peripheral component interconnect; GTL+: gunning transceiver logic; SSTL: stub-series terminated logic; CTT: center tap terminated; AGP: advanced graphics port
