AR# 47975: 7 Series GTP Transceivers - BUFG/BUFH must be used between TX/RXOUTCLK and MMCM/PLL
7 Series GTP Transceivers - BUFG/BUFH must be used between TX/RXOUTCLK and MMCM/PLL
The 7 Series FPGAs GTP Transceivers User Guide (UG482) v1.1.1 incorrectly states that BUFR can be used between TXOUTCLK/RXOUTCLK and MMCM or PLL in the larger Artix-7 devices XC7A200T and XC7A350T.
BUFG, or BUFH, with certain limitations, must be used between TXOUTCLK/RXOUTCLK and MMCM or PLL in all Artix-7 devices. For details about placement constraints and restrictions on clocking resources (MMCM, BUFR, BUFH, BUFG, etc.), refer to UG472, 7 Series FPGAs Clocking Resources User Guide.
The incorrect information about BUFR usage is fixed in the next revision of the user guide, v1.2.