LVDS Signal DC offset and AC Swing

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Why do you refer to Cyclone V GX instead of Cyclone 10 GX documents? The relevant are the transceiver PHY user guide https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/hb/cyclone-10/ug_cyclone10_xcvr_phy.pdf and the datasheet https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/hb/cyclone-10/c10gx-51002.pdf

However neither C5GX nor C10GX have programmable transceiver Vocm level. Datasheet specifies 0.65 V for C5GX and 0.4/0.5 V for C10GX. Setting transceiver Vocm to 1.25 V LVDS value is simply impossible due to the low transceiver supply voltage.

You didn't yet answer the question about AC coupling option. What's your application?

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Hi, which table did you use to get Vocm 0.4/0.5V for C10GX in C10GX Datasheet? Table 17 in the transceiver PHY user guide https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/hb/cyclone-10/ug_cyclone10_xcvr_phy.pdf says that "Output Swing Level (VOD) 0-31 " based on VCCT. If VCCT is 1.0V and if I pick "Output Swing Level (VOD)" as 200 mV, is Vocm still around 0.4V/0.5V or will it be around 100 mV ( mid range of 200 mV ) ? Fifure 166 Transmit buffer in the transceiver PHY user guide https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/hb/cyclone-10/ug_cyclone10_xcvr_phy.pdf shows VCM for TX. Where is this value coming from?