Chip combines clock IC and quartz crystal reference

Silicon Labs claims that its Si5332 portfolio replaces clocks, oscillators, buffers and complete clock trees. The ‘clock tree on a chip’ adds multi-profile support and an integrated crystal option, adds the company.

The new versions have been added to the Si5332 any-frequency clock portfolio. They combine the clock IC and a quartz crystal reference inside the same package, simplifying board layout and design. The all-in-one Si5332 guarantees reliable start-up and operation over the lifetime of the product, claims the company, which points out that sourcing the clock IC and crystal from different suppliers can risk interoperability issues. Silicon Labs is also introducing multi-profile support, available across the entire Si5332 family, enabling developers to consolidate multiple clock tree configurations into a single part number.

Traditional clock generators rely on an external, discrete quartz crystal frequency reference. The crystal interface circuit must be carefully designed for capacitive load matching to ensure accurate clock synthesis. To minimise the risk of noise coupling, designers typically do not route high-speed signals near crystals, which limits PCB routing flexibility.

The Si5332 clock generator addresses these design limitations by integrating a high-quality crystal reference inside the package. This not only simplifies the design, it also minimises the overall PCB footprint and maximises PCB routing flexibility, claims Silicon Labs. The crystal is shielded from external PCB noise, enabling the Si5332 integrated crystal device to offer lower jitter (175fs RMS 12kHz to 20MHz) compared to versions of the Si5332 using an external source (190fs RMS).

The Si5332 clock leverages 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 to 3.3V VDDO, the Si5332 interfaces to a broad range of FPGAs, ASICs, Ethernet switches/PHYs, processors, SoCs, and high-speed SerDes including PCIe. Collectively, these features enable the Si5332 to consolidate an entire clock tree in a single IC, concludes Silicon Labs.

The multi-profile feature enables consolidation of up to 16 clock tree configurations in a single IC. A single Si5332 part number can now replace crystal oscillator (XO) + buffer, clock generator, and clock generator + buffer clock trees. Each configuration is pin-selectable using hardware pins, eliminating the need for a serial interface to reconfigure the device to support different frequencies. Rather than sourcing different timing devices to support different combinations of frequencies, the multi-profile feature streamlines device qualification across different platforms and designs.

The Si5332 clock generators are supported by Silicon Labs’ ClockBuilder Pro (CBPro) software, which simplifies device configuration and customisation.

Samples and production quantities of Silicon Labs’ Si5332 clock generators are available now in a choice of 32-, 40- or 48-pin QFN packages and six, eight or 12 output options.