Silicon Labs’ “clock tree on a chip” portfolio simplifies board layout and design

By Gina Roos, editor-in-chief

Silicon Labs has expanded its Si5332 any-frequency clock portfolio
with new devices that combine the clock IC and a quartz crystal reference in
the same package, which simplifies board layout and design. The chip reduces
the risk of interoperability issues compared to other solutions that source the
parts separately from different suppliers, said the company. Silicon Labs guarantees
reliable start-up and operation of the all-in-one Si5332 over the lifetime
of the product.

The company
is also introducing multi-profile support available across the entire Si5332
family. This will enable developers to consolidate multiple clock tree
configurations into a single part number. The multi-profile feature enables the
consolidation of up to 16 unique clock tree configurations in a single IC. This
means a single Si5332 part can replace a crystal oscillator (XO) + buffer,
clock generator, and clock generator + buffer clock trees.

By integrating
the crystal reference inside the package, the Si5332 clock generator addresses
the design limitations in traditional clock generators that rely on an external
discrete quartz crystal frequency reference, said Silicon Labs.

“The crystal
interface circuit must be carefully designed for capacitive load matching to
ensure accurate clock synthesis. To minimize the risk of noise coupling,
designers typically do not route high-speed signals near crystals, which limits
printed circuit board (PCB) routing flexibility,” said Silicon Labs.

The new chip
also reduces the overall PCB footprint and improves PCB routing flexibility, while
the crystal is shielded from external PCB noise, enabling the Si5332 integrated
crystal device to offer lower jitter (175 fs RMS 12 kHz to 20 MHz) compared to
versions of the Si5332 using an external source (190 fs RMS), according to the

“The Si5332
clock generator offers the industry’s highest level of timing integration,
enabling complete clock tree consolidation in 10/25/100G data center,
communications, industrial and broadcast video applications,” said James
Wilson, general manager of timing products at Silicon Labs, in a statement.
“This comprehensive timing solution reduces supply chain complexity since it’s
sourced from a single supplier, Silicon Labs.”

The Si5332
clock uses Silicon Labs’ MultiSynth technology to provide any-frequency,
any-output clock syntheses with excellent jitter performance. Supporting up to
12 clock outputs, selectable signal formats per output clock (LVDS, LVPECL, HCSL,
LVCMOS) and independent 1.8-V to 3.3-V VDDO, the Si5332 interfaces to a range
of FPGAs, ASICs, Ethernet switches/PHYs, processors, SoCs, and high-speed

can use Silicon Labs’ ClockBuilder Pro (CBPro) software for device configuration
and customization, enabling them to tailor a clock solution to their specific
requirements and receive samples in two weeks. The CBPro generates a custom
orderable part number for each device with no minimum order quantity or
non-recurring engineering fees or restrictions.

Samples and
production quantities of the Si5332 clock generators are available now in
32/40/48-pin QFN packages with 6/8/12-output options. Pricing starts at $4.67
in quantities of 10,000. Clock and oscillator evaluation boards are available;
pricing ranges from $149 to $199.