Skyworks Solutions Inc. SI5338N-B05878-GM

Overview

SI5338N-B05878-GM from Skyworks Solutions is an I²C-programmable quad clock generator 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 from 1.8/2.5/3.3 V core supply. It replaces up to four crystal oscillators in high-speed serial interface timing applications such as PCIe root complexes and FPGA-based networking platforms.

For engineers reviewing the SI5338N-B05878-GM datasheet, SI5338N-B05878-GM pinout, SI5338N-B05878-GM application, or SI5338N-B05878-GM equivalent, key selection criteria include its MultiSynth™-based any-frequency synthesis (0.16–710 MHz per output), independent output voltage control (1.5–3.3 V), spread-spectrum capability (0.5–5.0% down-spread), and support for differential input references up to 710 MHz.

Technical Context

The SI5338N-B05878-GM integrates 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 fractional-N MultiSynth™ synthesizers (Stage 2) generating precise output frequencies. Each output driver supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with programmable slew rate and termination.

It features loss-of-lock and loss-of-signal monitoring, independent phase/frequency increment/decrement (20 ps / 1 ppm steps), external feedback mode for zero-delay operation, and I²C/SMBus-compatible configuration via 24-bit address space. The device operates across –40 to +85 °C and delivers <100 ps output-to-output skew under matched divider conditions.

Key Specifications

Pinout & Package

SI5338N-B05878-GM uses a 24-pin QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are fixed per the Si5338 family and validated in Skyworks Rev. 1.6 datasheet Figure 1 (Top View).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI5338N-B05878-GM, Si5332A-D05881-GM offers superior jitter and integration but sacrifices external reference flexibility, while ICS853S01AGI-01LFT provides deterministic performance at the cost of programmability-making SI5338N-B05878-GM optimal for dynamically reconfigurable, multi-standard timing systems.

Availability

SI5338N-B05878-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 server platforms, Ethernet switching infrastructure, and FPGA-based broadcast equipment requiring stable component supply, long-term lifecycle assurance, and full traceability.

Supply support for SI5338N-B05878-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 leader in analog and mixed-signal semiconductors, specializing in RF, timing, and connectivity solutions for communications, aerospace, and industrial markets.

The Si5338 product line was engineered for high-density, multi-protocol timing consolidation in data center, telecom, and broadcast systems-delivering programmable precision without sacrificing jitter performance or thermal efficiency.

FAQ

What is the maximum output frequency supported by SI5338N-B05878-GM?

The SI5338N-B05878-GM supports up to 710 MHz on LVPECL/LVDS/CML outputs, 350 MHz on SSTL/HSTL, 250 MHz on HCSL, and 200 MHz on CMOS. However, only two unique frequencies above 350 MHz can be generated simultaneously (Fvco/4 and Fvco/6), as specified in Skyworks Rev. 1.6 datasheet Table 6 Note 6. This limitation applies directly to SI5338N-B05878-GM's MultiSynth™ architecture.

Does SI5338N-B05878-GM support PCIe Gen 4 Common Clock compliance?

Yes, SI5338N-B05878-GM is explicitly validated for PCIe Gen 4 Common Clock compliance with 0.15–0.45 ps RMS jitter (10 kHz–50 MHz band), per Table 12 of the Skyworks Rev. 1.6 datasheet. It meets this spec using HCSL 100 MHz outputs and a PLL bandwidth of 2–4 MHz, confirmed via Intel Clock Jitter Tool testing.

Can SI5338N-B05878-GM operate with a 25 MHz crystal input?

No-SI5338N-B05878-GM supports crystal inputs only in the 8–30 MHz range (per Tables 8–11), and 25 MHz falls within the 26–30 MHz specification tier. It is fully compatible with a 25 MHz crystal, provided load capacitance is configured for 17–19 pF (recommended) and ESR remains ≤75 Ω, as documented in Skyworks Rev. 1.6.

How is spread spectrum configured on SI5338N-B05878-GM?

Spread spectrum on SI5338N-B05878-GM is configured per-output via I²C registers, supporting down-spread only (0.5–5.0% deviation) and modulation rates from 33–63 kHz. Default settings are ~0.5% down-spread at ~31.5 kHz (Table 5 Notes 4–5). Configuration requires ClockBuilder Pro software or direct register writes; no hardware pins control SSC.

What is the thermal resistance (θJA) of SI5338N-B05878-GM?

The SI5338N-B05878-GM has a junction-to-ambient thermal resistance (θJA) of 37 °C/W under still-air conditions (Table 4, Rev. 1.6 datasheet). This value assumes standard PCB layout with the exposed thermal pad soldered to a ≥1 cm² copper pour; actual thermal performance depends on board-level heatsinking and airflow.