EP2AGX95EF29C6N Datasheet, PDF (198/380 Pages) Altera Corporation – Device Interfaces and Integration

6–34
Chapter 6: I/O Features in Arria II Devices
Termination Schemes for I/O Standards
mini-LVDS
Arria II GX devices support true mini-LVDS with a three-resistor network using two
single-ended output buffers for external three-resistor networks.
For Arria II GZ devices, use two single-ended output buffers with external one- or
three-resistor networks (mini-LVDS_E_1R or mini-LVDS_E_3R). Arria II GZ row I/O
banks support mini-LVDS output using true LVDS output buffers without an external
resistor network.
Figure 6–18 shows the one-resistor and three-resistor topology for RSDS and
mini-LVDS I/O standard termination.
Figure 6–18. RSDS and mini-LVDS I/O Standard Termination for Arria II Devices (Note 1)
Termination
External
On-Board
Termination
One-Resistor Network (RSDS_E_1R and mini-LVDS_E_1R) (2)
≤1 inch
50 Ω
RP
100 Ω
50Ω
Transmitter
Receiver
Three-Resistor Network (RSDS_E_3R and mini-LVDS_E_3R)
Transmitter
≤1 inch
RS
RP
RS
50 Ω
50 Ω
100 Ω
Receiver
OCT
Transmitter
≤1 inch
RP
50 Ω
50 Ω
Arria II OCT
100 Ω
Receiver
Transmitter
≤1 inch
RS
RP
RS
Arria II OCT
50 Ω
50 Ω
100 Ω
Receiver
Notes to Figure 6–18:
(1) R_p = 170  and R_s= 120 
(2) mini-LVDS_E_1R is applicable for Arria II GZ devices only.
A resistor network is required to attenuate the LVDS output-voltage swing to meet
RSDS and mini-LVDS specifications. You can modify the three-resistor network
values to reduce power or improve the noise margin. The resistor values chosen
should satisfy the equation shown in Equation 6–1.
Equation 6–1. Resistor Network
RS x ^RP
2
RS + ^RP
2
= 50 Ω
1 To validate that custom resistor values meet the RSDS requirements, Altera
recommends performing additional simulations with IBIS models.
f For more information about the RSDS I/O standard, refer to the RSDS Specification
from the National Semiconductor website at www.national.com.
f For more information about the mini-LVDS I/O standard, see the mini-LVDS
Specification from the Texas Instruments website at www.ti.com.
Arria II Device Handbook Volume 1: Device Interfaces and Integration
December 2011 Altera Corporation