This document introduces the use of Altera Cyclone devices in multiple-voltage systems, including the MultiVolt™ I/O operation capability of the devices, hot-socketing, power-up sequence flexibility, power-on reset, etc.
This document chapter explains how to use Cyclone devices in multiple-voltage systems by separating the core and I/O supply voltages. It details the MultiVolt I/O operation capability, which allows the device to interoperate with other devices using different voltage levels on the same PCB. The text also covers I/O standards supported by the device family, including 3.3-V, 2.5-V, 1.8-V, and 1.5-V LVTTL/LVCMOS, as well as LVDS and SSTL standards.
| Supported I/O Standards | 3.3-V LVTTL/LVCMOS, 2.5-V LVTTL/LVCMOS, 1.8-V LVTTL/LVCMOS, 1.5-V LVCMOS, LVDS, SSTL-2 Class I and II, SSTL-3 Class I and II |
|---|---|
| PCI I/O Standard Support | 3.3-V PCI |
| Maximum DC Current during Hot-Socketing | Less than 300 µA |
| Maximum AC Current during Hot-Socketing | Less than 8 mA |
Yes, all devices in the Cyclone family are designed to support hot-socketing without special design requirements.
Yes, you can change the VCCIO supply voltage while the board is powered-up, provided VCCINT and VCCIO stay within correct operating conditions.
Yes, Cyclone devices maintain a reset state until voltage is within operating range to prevent incorrect initialization.