13 | Keysight | U4164A Logic Analyzer Module - Data Sheet
Signal Integrity Insight Made Fast and Easy
As timing and voltage margins continue to shrink, confidence in signal integrity becomes
an increasingly vital requirement in the design validation process. Eye scan lets you acquire
qualitative signal integrity information in a matter of minutes on all the buses in your design
under a wide variety of operating conditions.
– Identify problem signals quickly for further investigation with an oscilloscope.
– Results can be viewed for each individual signal or as a composite of multiple signals or
buses.
The ability to qualify scans of any signal from any combination of other signals, full triggering
capabilities for scan qualification, and customizable viewing windows allow you to sample
only when the qualifying signal is active and see specific system activity of interest. Eye scan
technology in the U4154B provides insights that can’t be achieved as easily with any other test
method. DDR eye scan automatically groups signals so you can quickly spot byte lane related
signal integrity problems. Scans can be qualified based on state trigger criteria, providing
unique insight. For example, read and write scans can be separated. Signal trace mode scan
allows you to gather signal integrity information on two read or write cycles separated by only
one cycle.
DDR eye scan is available at no charge as part of the Keysight B4661A memory analysis
software package that can be downloaded from:
www.keysight.com/find/B4661A
Figure 7 shows a scan using signal trace mode where the samples in a DDR/LPDDR data
burst are displayed in sequence. Figure 8 shows DDR3 DQ (data bits) scanned in overlay mode
where the samples in the burst are scanned so that they overlay. Overlay mode provides the
worst case eye, which allows for the most accurate sample position for the state mode sample
positions.
Figure 7. Burst qualified eye scan allows you to view the activity on the signals only when a burst is taking
place. The screenshot above shows DDR4 2400 Mb/s read DQS 0-3 scanned in signal trace mode with no
back-to-back bursts, allowing the user to view the DDR4 read strobes relative to each other, including the
strobe pre-embles.
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