Skyworks Solutions Inc. SI5335A-B04277-GMR

Overview

SI5335A-B04277-GMR from Skyworks Solutions is a web-customizable, quad-output clock generator/buffer IC with MultiSynth fractional synthesis, delivering four independent non-integer-related frequencies up to 350 MHz, 0.7 ps RMS phase jitter, PCIe Gen 1–4 common clock compliance, and support for LVPECL/LVDS/HCSL/CMOS/SSTL outputs in a 4×4 mm 24-QFN package. It serves as a single-chip replacement for multiple oscillators and clock ICs in high-speed serial interface timing systems.

For engineers reviewing the SI5335A-B04277-GMR datasheet, SI5335A-B04277-GMR pinout, SI5335A-B04277-GMR application, or SI5335A-B04277-GMR equivalent, this device enables precise multi-frequency clock synthesis with configurable loop bandwidth (475 kHz / 1.6 MHz), loss-of-signal detection, spread spectrum control, and pin-selectable frequency plans - critical for PCIe jitter attenuation, Ethernet switch timing, and FPGA/processor clocking.

Technical Context

The SI5335A-B04277-GMR integrates a single PLL with two selectable loop bandwidths (475 kHz or 1.6 MHz) and four independent MultiSynth fractional dividers, each driving one output bank. Its architecture supports both clock generator mode (full synthesis from crystal or reference input) and buffer mode (PLL bypass with <4 ns propagation delay).

Input flexibility includes differential (LVDS/LVPECL/CML/HCSL, 10–350 MHz), single-ended CMOS (10–200 MHz), or 25/27 MHz crystal; output drivers are independently configurable per bank for voltage (1.5/1.8/2.5/3.3 V), format, and enable control, with five user-assignable pins (P1–P3, P5, P6) supporting SSENB, RESET, OEB, and FS[1:0].

Key Specifications

Pinout & Package

SI5335A-B04277-GMR uses a 24-pin QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Rev. 1.4 datasheet Figure 2 (Top View) and Section 10 (Pin Descriptions).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D05889-GM and ICS8430I-01T, the SI5335A-B04277-GMR uniquely balances 4-output flexibility, web-customizable synthesis, PCIe Gen 4 readiness, and compact 24-QFN packaging - making it optimal for space-constrained, multi-protocol systems requiring field-upgradable timing configurations.

Availability

SI5335A-B04277-GMR is available at Aetrix Electronics and suitable for PCIe Gen 4 server motherboards, 100G Ethernet line cards, and FPGA-based AI inference accelerators requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SI5335A-B04277-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 for wireless, broadband, automotive, and industrial markets.

The SI5335A-B04277-GMR belongs to Skyworks' Si5335 family of any-frequency clock generators, designed specifically to replace multiple discrete oscillators and clock ICs in high-speed serial interface systems requiring PCIe, Ethernet, and broadcast timing compliance.

FAQ

What is the primary function of the SI5335A-B04277-GMR?

The SI5335A-B04277-GMR is a quad-output, web-customizable clock generator/buffer IC that synthesizes four independent, non-integer-related frequencies up to 350 MHz using Skyworks' MultiSynth fractional divider technology. It operates as either a full clock generator (with PLL) or a low-latency buffer (PLL bypass), supporting PCIe Gen 1–4, Ethernet, and broadcast timing standards in a single 24-QFN package.

Does the SI5335A-B04277-GMR support PCIe Gen 4 timing requirements?

Yes, the SI5335A-B04277-GMR is PCIe Gen 4 common clock compliant, delivering ≤0.45 ps RMS jitter (12 kHz–20 MHz) at 100 MHz HCSL output with 1.6 MHz loop bandwidth, meeting the PCI-SIG Base Specification 4.0 rev. 0.5 requirement. It also supports Gen 4 SRNS mode with 0.15–0.32 ps RMS jitter depending on configuration.

How many independent output voltage rails does the SI5335A-B04277-GMR provide?

The SI5335A-B04277-GMR provides four independent output supply rails - VDDO0 through VDDO3 - each configurable for 1.5 V, 1.8 V, 2.5 V, or 3.3 V. This allows mixed-signal interfacing (e.g., 1.8 V LVDS to FPGA transceivers and 3.3 V CMOS to legacy microcontrollers) without external level shifters.

Can the SI5335A-B04277-GMR operate without an external crystal?

Yes, the SI5335A-B04277-GMR supports multiple reference inputs: external 25/27 MHz crystal (via XA/XB pins), single-ended CMOS (10–200 MHz), or differential clock (10–350 MHz). Crystal operation requires no external load capacitors due to integrated 18 pF capacitance; other inputs need proper AC coupling and termination per datasheet guidelines.

What is the purpose of the LOS pin on the SI5335A-B04277-GMR?

The LOS (Loss-of-Signal) pin on the SI5335A-B04277-GMR is an open-drain output that asserts low within 5 µs of detecting failure on the primary reference input (XA/XB). It enables system-level fault monitoring and automatic switchover to backup timing sources, critical for carrier-grade Ethernet and broadcast equipment requiring high availability.