(^36) DESIGN WORLD — EE NETWORK 6 • 2019 eeworldonline.com | designworldonline.com
Coupled
fields
Fringing
fields
Cross section of differential pair
Receiver
Driver
350 mV
Current
source 3.5 mA
100Ω
Typical LVDS setup
Testing LVDS devices
at the margins with an AWG
First introduced in 1994, low-voltage differential signaling (LVDS)
has gone on to become widely used in products such as LCD
panels, automotive infotainment systems, industrial cameras and
machine vision, notebook and tablet computers, communications
systems, and more. Unlike other 90s-era standards that have come
and gone, LVDS continues to thrive in its traditional applications
as well as in newer applications that require high-data-rate
transmissions including automotive radar and lidar, industrial,
Internet of Things (IoT), and high-energy physics applications.
The need for robust signal margin performance rises as a general-
purpose interface like LVDS is applied in these more demanding
settings. This testing requires robust signal generation to test and
stress LVDS receivers from R&D through to production. In the past,
these signals were generated in number of ways, ranging from use
of a data-pattern generator to development of custom FPGAs.
Those methods have become outdated with the introduction
of arbitrary waveform generators (AWG) which have the channel
counts and data rates needed to thoroughly test LVDS protocol
and receiver margins. LVDS applications often require a large
number of outputs, with over five differential pairs being the norm.
Advanced arbitrary waveform generators have
simplified the testing associated with communications
over low-voltage differential signaling lines.
CHRIS LOBERG | TEKTRONIX
LVDS is a differential
signaling system defined
under ANSI/TIA/EIA-644.
TEST & MEASUREMENT HANDBOOK
Tektronix — Test and Measurement HB 06-19.indd 36 6/7/19 1:49 PM
amelia
(Amelia)
#1