Skyworks Solutions Inc. SI5332AC08943-GM1

Overview

SI5332AC08943-GM1 from Silicon Labs is a 6-output, 32-pin QFN programmable clock generator with MultiSynth™ fractional synthesis, delivering 190 fs RMS phase jitter (external crystal), 5–333.33 MHz differential output frequency range, and support for LVDS/LVPECL/HCSL/LVCMOS signal formats per output. It serves as a single-chip clock tree solution in Ethernet switch timing subsystems.

For engineers reviewing the SI5332AC08943-GM1 datasheet, SI5332AC08943-GM1 pinout, SI5332AC08943-GM1 application, or SI5332AC08943-GM1 equivalent, key selection considerations include its 6-differential-output capability in 5×5 mm QFN, external 16–50 MHz crystal interface, independent VDDO per output bank, I²C programmability, and PCIe Gen1–4/SRIS compliance.

Technical Context

The SI5332AC08943-GM1 implements a two-stage synthesis architecture: a wideband PLL locks to an external 16–50 MHz crystal (XA/XB pins), then feeds up to three independent MultiSynth fractional dividers and five integer dividers. Its cross-point mux routes any synthesized or divided frequency to any of six differential outputs.

Each output supports user-configurable format (LVDS/LVPECL/HCSL/LVCMOS), skew adjustment in 35 ps steps (±122.5 ps), and synchronous enable/disable. Input selection is configurable via register or two universal hardware pins (CLKIN_SEL[1:0]), and initialization loads factory-programmed NVM configuration at power-up.

Key Specifications

Pinout & Package

SI5332AC08943-GM1 uses a 32-pin QFN package (5 mm × 5 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per the Si5332A/B/C/D 32-QFN pinout (Datasheet Rev. 1.1, Section 6.3).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable clock generator applications.

Compared with SI5332BC08943-GM1, the SI5332AC08943-GM1 provides 66% higher maximum output frequency (333.33 MHz vs. 200 MHz), enabling direct support for 25G Ethernet and PCIe Gen4 without external frequency multiplication. Compared with SI5332AC08944-GM1, it delivers a distinct factory-programmed configuration - both share identical silicon and pinout but differ solely in stored NVM settings.

Availability

SI5332AC08943-GM1 is available at Aetrix Electronics and suitable for Ethernet switches, server motherboards, broadcast video gateways, and industrial embedded controllers requiring stable component supply across multi-year production cycles.

Supply support for SI5332AC08943-GM1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Silicon Labs is a fabless semiconductor company specializing in timing, wireless, and IoT solutions, with headquarters in Austin, Texas.

The Si5332 family was designed to replace multiple fixed-frequency clock sources with a single programmable device for high-speed communications infrastructure, targeting servers, networking, and broadcast equipment where jitter, flexibility, and space savings are critical.

FAQ

What is the maximum differential output frequency supported by the SI5332AC08943-GM1?

The SI5332AC08943-GM1 supports differential output frequencies from 5 MHz to 333.33 MHz. This upper limit is specified for integer-mode synthesis and applies to all six differential outputs. The 333.33 MHz capability enables direct generation of 25G Ethernet reference clocks and PCIe Gen4 x16 link rates without external frequency multiplication circuits.

Does the SI5332AC08943-GM1 include an embedded crystal?

No, the SI5332AC08943-GM1 does not include an embedded crystal. It belongs to the Si5332A/B/C/D series, which requires an external 16–50 MHz fundamental-mode crystal connected to the XA/XB pins. Embedded crystal variants (Si5332E/F/G/H) use a factory-integrated 50 MHz MEMS resonator and carry different part number suffixes.

How many independent voltage domains does the SI5332AC08943-GM1 support for its clock outputs?

The SI5332AC08943-GM1 supports six independent output supply domains via dedicated VDDO0–VDDO5 pins. Each pin can be set to 1.5 V, 1.8 V, 2.5 V, or 3.3 V, allowing simultaneous generation of clocks for mixed-voltage subsystems - for example, 1.8 V for FPGA transceivers, 2.5 V for PHYs, and 3.3 V for microcontrollers - without external level shifters.

Can the SI5332AC08943-GM1 be reprogrammed after soldering to the PCB?

Yes, the SI5332AC08943-GM1 supports in-circuit programming via its I²C interface (SCLK/SDATA pins). ClockBuilder Pro-generated configurations can be written to non-volatile memory (NVM) post-assembly. The device also offers OTP-defined power-up modes that allow host processors to write partial register sets before activating outputs, enabling field firmware updates without reflashing the entire NVM.

Is the SI5332AC08943-GM1 compliant with PCIe Gen4 timing specifications?

Yes, the SI5332AC08943-GM1 meets PCIe Gen4 SRIS (Scalable Reliable Interconnect Specification) requirements with 190 fs RMS phase jitter (12 kHz–20 MHz integration bandwidth) when using an external crystal. Its low jitter, programmable spread spectrum, and support for 100 MHz, 125 MHz, and 250 MHz PCIe reference frequencies make it suitable for root complex and endpoint timing in Gen4 and backward-compatible Gen3/2/1 designs.