Forum Discussion
Oliver_I_Sedlacek
Contributor
ContributorCyclone IV GX LVDS placement and termination
I need to place 48 LVDS receiver pairs on to a 484 pin Cyclone IV GX package. I've been studying the Cyclone 4 handbook, specifically section 6 Table 6.2 and I'm still confused. 1. According to this...
- Hi,
1. "true LVDS" refers to transmitters, these banks support LVDS TX IO-standard, the other banks support only emulated LVDS with three resistor network. LVDS RX can be configured for all banks.
2. Cyclone III, IV and 10LP doesn't provide on-chip parallel termination (Rd) for LVDS RX. External 100 ohm resistors are required.
FvM
Super Contributor
Super ContributorHi,
1. "true LVDS" refers to transmitters, these banks support LVDS TX IO-standard, the other banks support only emulated LVDS with three resistor network. LVDS RX can be configured for all banks.
2. Cyclone III, IV and 10LP doesn't provide on-chip parallel termination (Rd) for LVDS RX. External 100 ohm resistors are required.
1. "true LVDS" refers to transmitters, these banks support LVDS TX IO-standard, the other banks support only emulated LVDS with three resistor network. LVDS RX can be configured for all banks.
2. Cyclone III, IV and 10LP doesn't provide on-chip parallel termination (Rd) for LVDS RX. External 100 ohm resistors are required.
- Oliver_I_Sedlacek
Thanks, a really useful answer. I only need 6 LVDS transmitters so that shouldn't be a problem.
Re OCT you don't include the Cyclone IV GX in your list, is it different from the the Cyclone IV E?
Before I wrap this up, is there a diagram for the three resistor network for LVDS? Figures 6-7 and 6-8 only show HSTL and SSTL with four resistors.
