A Complete PLL Compliance Test Solution
for PCIe Components and Add-In Cards
- Simple Compliance Test
- Accurate
- Repeatable
- Single Instrument Solution
The BERTScope PLA is an easy to use, single
instrument measurement solution for PLL loop response characterization
and compliance testing to the PCIe specifications. The instrument
features fast setup as well as accurate and repeatable results.
Ease of Use
Of all the methods for testing PLL compliance in PCIe components
and add-in cards, the BERTScope PLA analysis instruments are
the easiest to set up and use. Simply connect four cables
to the Compliance Base Board, plug the instrument’s
USB cable into any PC, load the software, and you are up and
testing. No specialized instrument setups or calibration runs
are required.
Pass-Fail determination is just as easy.
The simplified user interface allows any user to quickly get
the compliance test results they need, without complicated
cursor setup or interpretation that is required using other
methods.
 Works with All
PCIe PLL Topologies
The BERTScope PLA reference generator maintains a duty cycle
of exactly 50%, regardless of the amount of frequency modulation,
allowing the instrument to test any PLL topology. Other instruments
amplitude-modulate the 100 MHz reference oscillator, essentially
modulating the duty cycle rather than the period. While this
technique works with single-edge phase detectors, it won’t
work with PLLs using dual-edge detectors that new designs incorporate
to reduce the multiplier ratio, resulting in lower clock jitter.
Fast
The instrument sweeps the full range of test frequency in
under 15 seconds. Unlike spectrum analyzers, which must reduce
the sweep time to achieve good frequency resolution, the BERTScope
PLA analysis instrument always maintains full resolution without
slowing down test time. The fast measurements improve design
confidence, allowing the characterization of a large number
of devices without adding extra days of characterization to
a design introduction schedule.
Highly Accurate and Repeatable
The BERTScope PLA does not sacrifice accuracy and resolution
to achieve ease of use and fast test times. An amplitude measurement
resolution of 0.01 dB provides high confidence when testing
the peaking limit to the +1 dB allowed by the standard. Other
approaches have limited resolution of 0.5 or even 1 dB, limiting
the ability to accurately measure peaking and -3 dB bandwidth.
The high measurement resolution and clean
reference oscillator provide the granularity required for consistent
results – validated through dozens of tests at compliance
workshops. Other methods with limited resolution can give less
decisive results. Test made today with the BERTScope PLA will
agree with those made last week, or in another lab using a
different BERTScope PLA.
More than Just Compliance Testing
The BERTScope PLA provides additional measurements useful
for the PLL designer to characterize their design In addition
to directly measuring the edge density of the Tx data, the
BERTScope PLA can also generate a phase plot, allowing the
designer to see the phase margin of the PLL.
The instrument provides both high resolution
and high dynamic range — typically 75 dB. This allows
the user to see the transfer of low frequency jitter sources,
orders of magnitude below the PLL – 3 dB point. The SSC
modulation jitter component can be directly measured.
The CRJ 12500A-PCIe combines the powerful
spectral jitter analysis and instrumentation quality clock recovery functionality
of the CRJ 12500A with PCIe-PLL analysis. All
of the CRJ
12500A features and specifications are maintained in the CRJ
12500A-PCIe model. |
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