Skyworks Solutions Inc. SI5338C-B05278-GM

Overview

SI5338C-B05278-GM from Skyworks Solutions is a quad-output, I²C-programmable clock generator with MultiSynth™ frequency synthesis. It delivers four independent, any-frequency outputs (0.16–710 MHz) with 0.7 ps RMS typical phase jitter, PCIe Gen 1–4 common clock and Gen 3 SRNS compliance, and support for LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL output formats. It replaces up to four crystal oscillators in high-speed serial interface timing applications.

For engineers reviewing the SI5338C-B05278-GM datasheet, SI5338C-B05278-GM pinout, SI5338C-B05278-GM application, or SI5338C-B05278-GM equivalent, key selection criteria include differential output jitter performance, PCIe Gen 4 SRNS compliance, independent per-output voltage control (1.5–3.3 V), spread-spectrum capability (0.5–5.0% at 33–63 kHz), and 24-QFN package compatibility with space-constrained PCB layouts.

Technical Context

The SI5338C-B05278-GM implements a two-stage PLL architecture: a high-stability reference stage (with crystal or external clock input) feeding a fractional-N MultiSynth™ synthesis stage per output. Each of the four outputs features independent programmable dividers (R, M, P), enabling true zero-ppm frequency accuracy and glitchless 1 ppm frequency increment/decrement via pin or I²C control.

It supports flexible input references - 8–30 MHz crystal, 5–200 MHz CMOS, 5–350 MHz SSTL/HSTL, or 5–710 MHz differential - and provides independent output voltage per driver (1.5/1.8/2.5/3.3 V), phase adjustment (<20 ps steps), and configurable spread spectrum on any output (5–350 MHz, 0.5–5.0%, 33–63 kHz).

Key Specifications

Pinout & Package

SI5338C-B05278-GM is housed in a 24-lead, 4 × 4 mm QFN package with exposed thermal pad. Pin assignments follow Skyworks' standard Si5338 layout: dual differential inputs (IN1/IN2, IN5/IN6), two single-ended inputs (IN3, IN4), four differential output pairs (CLK0A/B–CLK3A/B), six VDDOx supply pins (VDDO0–VDDO3), dual core VDD, SCL/SDA/I²C interface, INTR alarm output, and ground/pad connections.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-B05278-GM, the SI5338C-B05278-GM provides identical hardware functionality but with a different factory OTP image optimized for custom frequency plans; versus LMK04832RHAT, it trades deterministic latency and ultra-low additive jitter for smaller size, lower power, and broader protocol coverage (PCIe, Ethernet, broadcast video) in a single device.

Availability

SI5338C-B05278-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 switch timing, Ethernet switching/routing, and broadcast video timing requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SI5338C-B05278-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 for wireless, broadband, automotive, and industrial markets.

The Si5338 product line was designed to replace multiple discrete oscillators and clock buffers in high-speed digital systems, delivering programmable, low-jitter timing with minimal footprint and software-defined flexibility.

FAQ

What is the default output configuration of the SI5338C-B05278-GM at power-up?

The SI5338C-B05278-GM boots with factory-programmed OTP settings that configure all four outputs as LVDS at user-defined frequencies stored in non-volatile memory. No external I²C programming is required for basic operation, though ClockBuilder Pro can reconfigure all parameters including format, frequency, and voltage. The SI5338C-B05278-GM retains its last programmed state across power cycles unless explicitly reset or reprogrammed.

Does the SI5338C-B05278-GM support PCIe Gen 4 Separate Reference No Spread (SRNS) mode?

Yes, the SI5338C-B05278-GM meets PCIe Gen 4 SRNS jitter requirements (≤0.32 ps RMS, 1.5–50 MHz band) when configured with a 2–5 MHz PLL bandwidth and 10 MHz CDR reference. This is verified per PCI-SIG specification using the Skyworks PCIe Clock Jitter Tool and confirmed in Table 12 of the official datasheet. The SI5338C-B05278-GM achieves this with its low-noise MultiSynth™ architecture and optimized loop filter settings.

Can the SI5338C-B05278-GM generate both differential and single-ended outputs simultaneously?

Yes, the SI5338C-B05278-GM supports mixed-mode operation: up to four differential outputs (CLK0A/B–CLK3A/B) and up to eight single-ended outputs (via internal termination and pin remapping), or any combination thereof. For example, CLK0A/B may be configured as LVDS while CLK1A operates as CMOS - each with independent voltage (1.5–3.3 V) and frequency (0.16–200 MHz for CMOS). This capability is documented in the "Highly-configurable output drivers" feature list and Table 6 of the datasheet.

What is the maximum output frequency achievable on a single SI5338C-B05278-GM output channel?

The SI5338C-B05278-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. Frequencies above 350 MHz are limited to two unique values simultaneously (Fvco/4 and Fvco/6) due to VCO constraints, as specified in Table 6 Note 6. All outputs maintain 0.7 ps RMS typical jitter at these rates when driven differentially with proper layout and termination.

How does the SI5338C-B05278-GM handle loss-of-signal or loss-of-lock conditions?

The SI5338C-B05278-GM monitors input reference integrity and PLL lock status continuously. Upon loss-of-signal (detection time: 2.6–5 µs) or loss-of-lock (5–10 ms), it asserts the open-drain INTR pin and updates internal status registers. These events trigger automatic failover to backup reference inputs if enabled, and can be polled or interrupted via I²C. The SI5338C-B05278-GM maintains output stability during transient faults and resumes normal operation automatically upon signal restoration.