Designing With Lvds; Blvds I/O Standard Support In Cyclone Iv Devices - Altera Cyclone IV Device Handbook

6–30

Designing with LVDS

Cyclone IV I/O banks support the LVDS I/O standard. The Cyclone IV GX right I/O
banks support true LVDS transmitters while the Cyclone IV E left and right I/O banks
support true LVDS transmitters. On the top and bottom I/O banks, the emulated
LVDS transmitters are supported using two single-ended output buffers with external
resistors. One of the single-ended output buffers is programmed to have opposite
polarity. The LVDS receiver requires an external 100- termination resistor between
the two signals at the input buffer.
Figure 6–12
LVDS output and input buffers.
Figure 6–12. Cyclone IV Devices LVDS Interface with True Output Buffer on the Right I/O Banks
Transmitting Device
txout +
txout -
Figure 6–13
using two single-ended output buffers and external resistors.
Figure 6–13. LVDS Interface with External Resistor Network on the Top and Bottom I/O Banks
Note to
(1) R

BLVDS I/O Standard Support in Cyclone IV Devices

The BLVDS I/O standard is a high-speed differential data transmission technology
that extends the benefits of standard point-to-point LVDS to multipoint configuration
that supports bidirectional half-duplex communication. BLVDS differs from standard
LVDS by providing a higher drive to achieve similar signal swings at the receiver
while loaded with two terminations at both ends of the bus.
Cyclone IV Device Handbook,
Volume 1
shows a point-to-point LVDS interface using Cyclone IV devices true
Cyclone IV Device
rxin +
50 Ω Cyclone IV
Device
100 Ω
Family Logic
50 Ω
Array
rxin -
Input Buffer
shows a point-to-point LVDS interface with Cyclone IV devices LVDS
Cyclone IV Device
Emulated
LVDS Transmitter
Resistor Network
Figure 6–13:
= 120 . R = 170 .
S P
Chapter 6: I/O Features in Cyclone IV Devices
txout +
50 Ω
50 Ω
txout -
Output Buffer
R S
50 Ω
R P
50 Ω
R S
High-Speed I/O Standards Support
Receiving Device
rxin +
100 Ω
rxin -
LVDS Receiver
100 Ω
March 2016 Altera Corporation
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