Skyworks Solutions Inc. SI5351C-B06452-GM

Overview

SI5351C-B06452-GM from Skyworks Solutions is an I²C-programmable CMOS clock generator with integrated VCXO architecture, synchronizing to an external CLKIN reference (10–100 MHz) while generating up to eight independent output frequencies from 2.5 kHz to 200 MHz with 0 ppm synthesis error. It operates from a 25/27 MHz crystal and supports 1.8/2.5/3.3 V output voltage levels per bank, targeting multi-clock-domain systems in networking and embedded timing applications.

For engineers reviewing the SI5351C-B06452-GM datasheet, SI5351C-B06452-GM pinout, SI5351C-B06452-GM application, or SI5351C-B06452-GM equivalent, key selection considerations include external reference synchronization capability, per-output spread spectrum control, static phase offset programming, glitchless frequency switching, and independent VDDO rail configuration for mixed-voltage system interfacing.

Technical Context

The SI5351C-B06452-GM implements a dual-PLL architecture where PLLA and PLLB accept either the internal crystal oscillator (25/27 MHz) or external CLKIN (10–100 MHz) via input crosspoint switches. Each PLL feeds eight high-resolution MultiSynth fractional dividers, enabling independent frequency synthesis per output.

It supports synchronous clock generation locked to CLKIN, configurable VCXO tuning (for Si5351B only - not applicable here), per-output rise/fall time control, adjustable output delay, and static phase offset alignment across outputs - all programmable via I²C interface with register-level access to all synthesis parameters.

Key Specifications

Pinout & Package

SI5351C-B06452-GM is housed in a 16-pin QFN package (3 mm × 3 mm, 0.5 mm pitch) with wettable flanks, rated for –40°C to +85°C operation. Thermal resistance θJA = 65°C/W on 4-layer board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5351B-B-GM1 and Si5351A-B-GM1, SI5351C-B06452-GM uniquely supports external CLKIN synchronization - making it the only option among the three for systems requiring deterministic phase alignment to a master clock, such as telecom line cards or synchronized sensor arrays.

Availability

SI5351C-B06452-GM is available at Aetrix Electronics and suitable for networking switch timing, audio/video clock synthesis, laser range finder control, and residential gateway timing requiring stable component supply and long-term design-in support.

Supply support for SI5351C-B06452-GM 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

Skyworks Solutions is a global semiconductor company specializing in analog and mixed-signal connectivity solutions, with leadership in RF, timing, and power management ICs.

The Si5351 family is designed for flexible, software-configurable clock generation in space-constrained, cost-sensitive applications - replacing crystals, oscillators, VCXOs, and discrete PLLs with a single programmable device.

FAQ

What reference inputs does the SI5351C-B06452-GM support?

The SI5351C-B06452-GM supports both an internal 25/27 MHz crystal (via XA/XB pins) and an external 10–100 MHz clock (via CLKIN pin). Unlike Si5351A/B variants, the SI5351C-B06452-GM requires CLKIN for synchronous operation and uses the crystal as a secondary or backup reference. This dual-reference capability enables robust failover timing architectures in mission-critical systems.

How many outputs does the SI5351C-B06452-GM provide, and what are their voltage options?

The SI5351C-B06452-GM provides four CMOS clock outputs (R0–R3) in its 16-QFN package. Each output bank has dedicated supply pins: R0/R1 powered by VDDOA and R2/R3 powered by VDDOB. Both VDDOA and VDDOB accept 1.8 V, 2.5 V, or 3.3 V independently - allowing mixed-voltage signaling without external level shifters, which is essential for interfacing with heterogeneous SoCs.

Does the SI5351C-B06452-GM support spread spectrum clocking?

Yes, the SI5351C-B06452-GM supports per-output spread spectrum clocking (SSC) with selectable down-spread (–0.1% to –2.5%) or center-spread (±0.1% to ±1.5%) at a fixed 31.5 kHz modulation rate. SSC is configured individually for each output via I²C registers, enabling targeted EMI reduction on specific high-speed interfaces (e.g., USB or PCIe traces) without affecting other clock domains.

Can the SI5351C-B06452-GM generate frequencies above 112.5 MHz?

Yes, the SI5351C-B06452-GM can generate frequencies up to 200 MHz per output, but only two *unique* frequencies above 112.5 MHz may be active simultaneously (e.g., 125 MHz and 150 MHz). Multiple outputs may replicate the same high-frequency signal (e.g., four 125 MHz clocks), but three distinct frequencies >112.5 MHz (e.g., 125/130/150 MHz) exceed internal resource limits and will not function as intended.

Is the SI5351C-B06452-GM pin-compatible with other Si5351 variants in the same package?

Yes, the SI5351C-B06452-GM in the 16-QFN package shares identical pinout and footprint with Si5351A-B-GM1 and Si5351B-B-GM1. However, functional differences exist: SI5351C-B06452-GM uses CLKIN as its primary reference and lacks VC pin functionality, while Si5351B-B-GM1 includes VC and omits CLKIN. Hardware design must route CLKIN appropriately and omit VC connections for full compatibility.