Forum Discussion
Honored ContributorLVDS Signal DC offset and AC Swing
Hi, What is the value of LVDS DC offset and LVDS AC Swing of Cyclone 10 GX devices?
16 Replies
Altera_Forum--- Quote Start --- LVDS outputs in GPIO banks are compatible with industry standard (Vocm 1.25V, 0.3 to 0.4V differential swing). --- Quote End --- is there any limitation in the cyclone 1o gx transceiver to create lvds signal defined as vocm 1.25 v , 0.3v to 0.4v differential swing with 2.5 gbps (1.25 ghz clock) by using the external shared clock with minimum 5 transceivers for source synchronous implementation ( 1 clock 4 data late at 2.5 gbps data rate with 1.25 ghz )?- Altera_Forum
LVDS outputs in GPIO banks are compatible with industry standard (Vocm 1.25V, 0.3 to 0.4V differential swing).
- Altera_Forum
For example, at Cyclone 10 GX datasheet ( https://www.altera.com/en_us/pdfs/literature/hb/cyclone-10/c10gx-51002.pdf ) page 19, VCM is defined as 1.25 V and Minimum Voltage swing is defined 200 mV ( 2*VID = 2 * 100 ) . There is no Max value is defined. For the data rates below 700 Mbps Swing from 0 to 1.85V, For data rates above 700 Mbps , Swing from 1,0 V to 1.6V ( For optimized LVDS receiver performance, the receiver voltage input range must be within 1.0 V to 1.6 V for data rates above 700
Mbps and 0 V to 1.85 V for data rates below 700 Mbps. ) is this correct? Am I missing something? - Altera_Forum--- Quote Start --- "High Speed Differential I/O is the dedicated I/O standard for the transmitter in Intel Cyclone 10 GX transceivers" --- Quote End --- I found in earlier documents that LVDS is specified from 1.0V to 1.4V . 0.3V Voltage Swing and Center 1.25V with Clear figures. I assume that same values are same for Cyclone 10 GX and newer devices. I couldn't find the values described like this in Cyclone 10 GX documentation.
- Altera_Forum
"High Speed Differential I/O is the dedicated I/O standard for the transmitter in Intel Cyclone 10 GX transceivers"
- Altera_Forum
1. It's all in the datasheet.
2. Which pins are you asking about, GPIO or transceiver output? Transceiver don't provide LVDS standard for DC coupled links.
