Skyworks Solutions Inc. SI5338A-B01085-GMR

Overview

SI5338A-B01085-GMR from Skyworks Solutions is an I²C-programmable quad clock generator IC with four independently configurable differential or single-ended outputs, 0.7 ps RMS typical phase jitter, PCIe Gen 1–4 Common Clock and Gen 3 SRNS compliance, and operation across –40 to +85 °C. It replaces up to four crystal oscillators in high-speed serial interface timing applications such as PCIe switch cards and 10 GbE line cards.

For engineers reviewing the SI5338A-B01085-GMR datasheet, SI5338A-B01085-GMR pinout, SI5338A-B01085-GMR application, or SI5338A-B01085-GMR equivalent, key selection criteria include its MultiSynth™-based any-frequency synthesis (0.16–710 MHz per output), independent output voltage control (1.5/1.8/2.5/3.3 V), spread-spectrum capability (0.5–5.0% down-spread), and 24-QFN package compatibility with space-constrained FPGA/ASIC clock trees.

Technical Context

The SI5338A-B01085-GMR implements a two-stage PLL architecture: a high-stability integer-N PLL (Stage 1) locks to one of six input references (crystal, CMOS, SSTL/HSTL, or differential), followed by four independent MultiSynth™ fractional-N synthesizers (Stage 2) generating precise output frequencies. Each output driver supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with programmable common-mode voltage and termination.

It features real-time frequency and phase adjustment via dedicated pins (FINC/FDEC, PINC/PDEC) enabling glitchless 1 ppm frequency steps and <20 ps phase steps, plus loss-of-lock and loss-of-signal monitoring via the INTR pin. The device operates from a single 1.8/2.5/3.3 V core supply with 45 mA typical current draw and integrates OTP NVM for factory or field programming.

Key Specifications

Pinout & Package

SI5338A-B01085-GMR is housed in a 24-lead QFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are fixed per the Si5338 family and validated for this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D06185-GM and ICS8430I-01T, the SI5338A-B01085-GMR uniquely balances field-programmability, PCIe Gen4 compliance, and compact 24-QFN packaging-making it optimal for mid-tier networking and broadcast equipment where design iteration and BOM consolidation matter.

Availability

SI5338A-B01085-GMR is available at Aetrix Electronics and suitable for PCIe switch timing, Ethernet line card clocking, broadcast video sync, and FPGA-based video processing requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production lots.

Supply support for SI5338A-B01085-GMR 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 precision analog ICs for infrastructure, automotive, and mobile markets.

The SI5338A-B01085-GMR belongs to Skyworks' Si5338 family of programmable clock generators, designed specifically for high-speed serial interface timing in datacenter, telecom, and broadcast systems where low jitter, multi-format flexibility, and software-defined configuration are critical.

FAQ

What is the primary function of the SI5338A-B01085-GMR in a PCIe Gen4 system?

The SI5338A-B01085-GMR serves as a common clock source for PCIe Gen4 endpoints, delivering four independent 100 MHz HCSL clocks with ≤0.45 ps RMS jitter (measured per PCIe Base Spec 4.0). Its MultiSynth™ engine ensures zero-ppm frequency accuracy, while spread-spectrum capability reduces EMI without violating PCIe jitter masks. SI5338A-B01085-GMR supports both common clock and SRNS architectures via configurable PLL bandwidth and feedback modes.

Does the SI5338A-B01085-GMR require an external crystal, or can it accept other reference inputs?

The SI5338A-B01085-GMR supports multiple reference sources: an 8–30 MHz fundamental-mode crystal connected to IN1/IN2, or single-ended (IN3/IN4) or differential (IN5/IN6) clock inputs ranging from 5–710 MHz. It does not integrate a crystal; the "B01085" suffix indicates factory-programmed configuration for a specific reference and output set, but the underlying SI5338A die retains full input flexibility.

How many different output voltage levels can be configured simultaneously on the SI5338A-B01085-GMR?

The SI5338A-B01085-GMR supports four independent output supply rails (VDDO0–VDDO3), each configurable for 1.5 V, 1.8 V, 2.5 V, or 3.3 V. This allows simultaneous driving of mixed-voltage devices-for example, 1.8 V LVDS SerDes, 2.5 V SSTL memory interfaces, and 3.3 V legacy logic-all from a single SI5338A-B01085-GMR without external level shifters.

Can the SI5338A-B01085-GMR generate frequencies above 350 MHz, and if so, how many outputs support it?

Yes-the SI5338A-B01085-GMR supports frequencies up to 710 MHz on LVPECL/LVDS/CML outputs. However, only two unique frequencies above 350 MHz can be generated simultaneously (Fvco/4 and Fvco/6), as constrained by the VCO operating range and synthesis architecture. All four outputs remain functional, but higher-frequency outputs must share one of those two VCO-derived rates.

Is the SI5338A-B01085-GMR pin-compatible with other Si5338 variants like the SI5338B or SI5338C?

Yes-the SI5338A-B01085-GMR uses the standard 24-QFN package and identical pinout across the entire Si5338A/B/C/D product family. Differences lie in internal OTP programming, supported frequency ranges, and feature enablement (e.g., Si5338C adds additional spread-spectrum options), but PCB layout and soldering are fully interchangeable for drop-in replacement within the same package variant.