Products in Focus | Frequency Management
to centralised data centres.
Considerations when choosing a
clocking solution
To meet the demands of AIoT and
5G applications, system engineers
must consider multiple factors when
choosing clock ICs or designing a
clock tree:
Performance of the reference
clock remains a top priority since
it directly impacts the quality of a
communications link. It’s a good idea
to choose a clocking solution that
provides significant jitter or phase
noise margin in comparison to system
requirements to ensure the quality of
the wired / wireless transmission.
Cross-talk is another issue to
consider, since multiple copies of
non-integer-related frequencies are
often needed to provide the necessary
reference clocking for an entire system.
The simplest approach is to use
multiple crystal oscillators, but a more
integrated solution may be preferable
to reduce BOM cost and complexity.
In these situations, clocking solutions
must be carefully selected to ensure
cross-talk and interference are
minimized. Cross-talk is configurationdependent,
so every new mix of
frequencies can create new challenges.
When multiple clock signals
are required, the optimal level of
integration that should be achieved
is an important consideration. For
simpler applications, designers may
opt to use one or two basic crystal
oscillators, but more complex
applications require more clocks and
more unique frequencies.
An integrated clock generator
solution is typically smaller, cheaper
and simpler to design with – but
multiple, local clock sources may be
better where it is difficult to route
clock signals over long traces due to
PCB design constraints and signal
integrity concerns.
Each application may require a
specific set of frequencies, which can
make it difficult to find appropriate
clocks. The best approach may be a
customized timing solution.
Broad range of timing solutions
When assessing timing requirements
for a complex AIoT or 5G application,
it’s important to look for a vendor
with a broad portfolio of clocking
solutions and deep expertise in highperformance
timing technology for
high-speed networks and data centres.
For example, Silicon Labs offers
best-in-class clock tree integration and
jitter performance across its portfolio,
enabling single-IC solutions for both
high-volume, cost-sensitive designs
as well as higher performance, more
demanding applications.
For some applications, solutions
with no external timing reference may
be best for space-constrained designs.
Over the past year, Silicon Labs has
introduced a broad portfolio of clock
generators and jitter attenuating clocks
that eliminate the need for an external
quartz crystal reference, simplifying
PCB layout while improving overall
system reliability. These devices are
particularly well-suited for spaceconstrained
applications that can’t
afford the larger footprint required by
more discrete solutions.
For the industrial IoT, Silicon Labs
offers a broad array of cost-effective
crystal oscillators and clock generators.
For autonomous driving applications,
Silicon Labs is developing new
automotive-qualified timing solutions
that will dramatically simplify clock
synthesis and distribution while also
increasing system-level reliability.
Always look for a vendor who is
committed to providing state-of-theart
timing solutions that not only
look to simplify clock synthesis and
timing synchronisation in AIoT and
5G applications but that can provide
best-in-class jitter and phase noise
performance and clocking integration,
that will enable you to adopt highly
optimised, single-chip solutions that
help accelerate the market adoption of
AIoT and 5G.
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