Article ID: 000081095 Content Type: Troubleshooting Last Reviewed: 09/11/2012
Why do my Stratix GX Quad PLLs toggle at the wrong rate ?
BUILT IN - ARTICLE INTRO SECOND COMPONENT
Description During board bring up the RX and TX PLLs seem to function but toggle at the wrong frequencies. This may be caused by the incorrect supply on the VCCA pins for the Quad. VCCA requires a 3.3V filtered supply. This is the only supply to the Quad that requires 3.3V, the remainder run at 1.5V. A common error is to connect the VCCA to 1.5v. This results in the the PLL toggling at a constant but incorrect frequency. Refer to the Stratix GX reference board for correct connectivity of the Quad supplies.