Skyworks Solutions Inc. SI5338Q-B05204-GMR

Overview

SI5338Q-B05204-GMR 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 across –40 to +85 °C in a 4 × 4 mm 24-QFN package. It replaces up to four crystal oscillators in FPGA, processor, and Ethernet switch timing systems.

For engineers reviewing the SI5338Q-B05204-GMR datasheet, SI5338Q-B05204-GMR pinout, SI5338Q-B05204-GMR application, or SI5338Q-B05204-GMR equivalent, key selection criteria include output format flexibility (LVPECL/LVDS/HCSL/CMOS/SSTL), independent per-output voltage (1.5/1.8/2.5/3.3 V), any-frequency synthesis capability (0.16–710 MHz), spread-spectrum control, and I²C/SMBus programmability with ClockBuilder Pro support.

Technical Context

The SI5338Q-B05204-GMR implements a two-stage PLL architecture: a high-stability reference stage followed by four independent MultiSynth™ fractional-N synthesizers, each driving one output pair. Input reference options include external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or differential (5–710 MHz).

Each output supports independent frequency, format, voltage, phase offset (<20 ps step), and spread-spectrum modulation (0.5–5.0% spread, 33–63 kHz rate). Loss-of-lock and loss-of-signal alarms, external feedback for zero-delay mode, and glitchless frequency increment/decrement (1 ppm steps) are integrated.

Key Specifications

Pinout & Package

SI5338Q-B05204-GMR is housed in a 24-lead, 4 × 4 mm QFN package with exposed thermal pad. Pin assignments follow standard Si5338 layout: dual differential inputs (IN1/IN2, IN5/IN6), single-ended inputs (IN3, IN4), four differential output pairs (CLK0A/B through CLK3A/B), six VDDOx supplies (VDDO0–VDDO3), dual VDD core pins, 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-B05204-GM and LMK04832RHAT, SI5338Q-B05204-GMR delivers identical jitter and frequency synthesis performance in a smaller footprint with simpler layout-no external filters or discrete regulators needed-making it optimal for high-density compute and telecom platforms where board area and design cycle time are critical.

Availability

SI5338Q-B05204-GMR is available at Aetrix Electronics and suitable for Ethernet switch/router, PCIe Gen 4 server boards, broadcast video timing, and telecom line card applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5338Q-B05204-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 Si5338 product line was designed specifically for high-performance, multi-protocol clock generation in datacenter, networking, and broadcast equipment-enabling consolidation of discrete oscillators into a single programmable device with sub-picosecond jitter.

FAQ

What is the default factory configuration of the SI5338Q-B05204-GMR?

The SI5338Q-B05204-GMR ships with preprogrammed OTP memory containing a validated clock tree configuration optimized for PCIe Gen 4 common clock operation: four 100 MHz HCSL outputs, 3.3 V VDDO, 3.3 V VDD core, and default spread-spectrum disabled. This allows immediate evaluation without I²C programming, though full reconfiguration remains possible via ClockBuilder Pro.

Does the SI5338Q-B05204-GMR support spread-spectrum clocking on all four outputs simultaneously?

Yes, the SI5338Q-B05204-GMR supports independent spread-spectrum modulation on any or all four outputs. Each output can be configured with unique spread percentage (0.5–5.0%), modulation rate (33–63 kHz), and direction (down-spread only). The feature is enabled per-output via dedicated registers and does not require shared resources or compromise jitter on non-SSC outputs.

Can the SI5338Q-B05204-GMR generate frequencies above 350 MHz on more than two outputs?

No. Per the Si5338 datasheet (Table 6, Note 6), only two unique frequencies above 350 MHz may be generated simultaneously-specifically Fvco/4 and Fvco/6. All other outputs above 350 MHz must replicate one of those two frequencies. For example, three 710 MHz outputs are not supported; maximum is two at 710 MHz plus two at ≤350 MHz.

What is the minimum input frequency supported in PLL bypass (clock buffer) mode for the SI5338Q-B05204-GMR?

In PLL bypass mode, the SI5338Q-B05204-GMR supports input frequencies as low as 1 MHz on single-ended inputs (IN3/IN4) and 5 MHz on differential inputs (IN1/IN2, IN5/IN6). However, loss-of-signal detection is only functional above 5 MHz; below that threshold, the INTR alarm will not assert during signal loss.

How does the SI5338Q-B05204-GMR handle power supply sequencing during startup?

The SI5338Q-B05204-GMR requires VDD core to be stable before VDDOx supplies; recommended ramp time is <100 ms. Internal power-on reset (POR) asserts for 2 ms after VDD stabilization, after which outputs become valid (tRDY = 2 ms max). No external sequencing circuitry is required, but violating the VDD-before-VDDO sequence may cause undefined output states or failed initialization.