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Altera_Forum
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16 years ago

Vccio level for LVDS IOs

Hi, AN479 says that LVDS ip & op must be powered with a 2.5V Vccio except: all LVDS inputs for cyclone device are powered by Vccint. The PCB with a cyclone was designed for other purpo...
Altera_Forum's avatar
Altera_Forum
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16 years ago

AN479 also tells:

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Supplying higher than supported voltage to VCCIO for LVDS would violate the rated specifications and may possibly damage the buffer.

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Apart from this, operating Cyclone at VCCIO of 3.3V with standard 3R network for LVDS output results in an incorrect common mode level, although it possibly works at lower rates. A 5R network with additional pull-down resistors could achieve correct LVDS levels.