Skyworks Solutions Inc. SI5351A-B06887-GTR

Overview

SI5351A-B06887-GTR from Skyworks Solutions is an I²C-programmable, 8-output CMOS clock generator with integrated VCXO, designed to replace crystals, crystal oscillators, and discrete PLLs in cost-sensitive embedded systems. It delivers up to eight independent, non-integer-related frequencies from 2.5 kHz to 200 MHz with 0 ppm synthesis error, operates from a 25 or 27 MHz crystal, and supports configurable output voltages (1.8/2.5/3.3 V) for mixed-signal timing in networking and audio/video equipment.

For engineers reviewing the SI5351A-B06887-GTR datasheet, SI5351A-B06887-GTR pinout, SI5351A-B06887-GTR application, or SI5351A-B06887-GTR equivalent, this device offers verified VCXO linearity (±5% gain error), low period jitter (70 ps pk-pk, all outputs active), glitchless frequency reprogramming, and I²C-based per-output spread spectrum control - critical for EMI reduction in compact PCB layouts.

Technical Context

The SI5351A-B06887-GTR implements a dual-PLL architecture (PLLA + PLLB) with high-resolution MultiSynth fractional dividers per output, enabling independent frequency synthesis without integer constraints. Its VCXO path uses a voltage-controlled crystal oscillator referenced to the same 25/27 MHz crystal, eliminating external pullable crystals while maintaining ±240 ppm total pull range at 3.3 V.

Each of the eight CMOS outputs features programmable rise/fall time, static phase offset, and separate VDDO supply pins for level translation. The device supports both free-running (XTAL-only) and VCXO-synchronized operation, with I²C register access to all synthesis parameters, OEB control, and SSEN spread-spectrum enable.

Key Specifications

Pinout & Package

SI5351A-B06887-GTR is housed in a 20-pin QFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are validated per Skyworks Si5351A 20-pin QFN specification (Rev. 1.3, Section 10.1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI5351A-B06887-GTR, Si5351B-B-GM provides identical VCXO functionality but no CLKIN option, while Si5351C-B-GM supports external reference locking but removes VC tuning - making SI5351A-B06887-GTR the only variant offering both VCXO and CLKIN flexibility in the 8-output 20-QFN form factor.

Availability

SI5351A-B06887-GTR is available at Aetrix Electronics and suitable for networking equipment, audio/video timing systems, and handheld instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5351A-B06887-GTR 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 Si5351 family is engineered as a highly flexible, I²C-programmable clock generator platform targeting cost-sensitive applications that require replacement of multiple crystals, oscillators, and PLLs with a single configurable IC.

FAQ

What is the maximum number of unique frequencies above 112.5 MHz supported by SI5351A-B06887-GTR?

The SI5351A-B06887-GTR supports only two unique frequencies above 112.5 MHz simultaneously across its eight outputs. For example, 125 MHz and 130 MHz may be assigned to different outputs, but a third distinct frequency >112.5 MHz (e.g., 150 MHz) will not synthesize correctly. This limitation arises from internal PLL bandwidth and MultiSynth divider resource constraints documented in Table 7 of the Skyworks datasheet.

Does SI5351A-B06887-GTR require external load capacitors for the 25 MHz crystal?

No - SI5351A-B06887-GTR includes programmable internal load capacitance (0, 6, 8, or 10 pF) selectable via register 183 bits 7:6. A standard 25 MHz AT-cut crystal with 6–10 pF load requirement operates without external capacitors. Crystals requiring 12 pF load use ≤2 pF additional external capacitance (e.g., 4 pF total split across XA/XB), per AN551 and datasheet Section 4.1.1.

Can SI5351A-B06887-GTR generate a 100 MHz PCIe Gen1 reference clock?

Yes - SI5351A-B06887-GTR generates 100 MHz with 0 ppm error and meets PCIe Gen1 jitter requirements. Measured period jitter is 70 ps pk-pk (all outputs active), well below the 100 ps pk-pk limit. The device supports HCSL-compatible swing and can be configured with appropriate drive strength and termination to match PCIe Gen1 specifications.

How does the VC pin function in SI5351A-B06887-GTR?

The VC pin on SI5351A-B06887-GTR provides analog voltage control for the integrated VCXO, enabling frequency tuning from ±30 ppm to ±240 ppm (configurable) at 3.3 V supply. It exhibits highly linear gain (18–150 ppm/V) across 10–90% of VDD and supports modulation bandwidth up to 10 kHz. All eight outputs track the same VC input, allowing synchronized tuning across multiple clock domains.

Is SI5351A-B06887-GTR pin-compatible with other Si5351 variants in the 20-QFN package?

Yes - SI5351A-B06887-GTR shares identical 20-pin QFN (4×4 mm) mechanical footprint and pinout with Si5351B-B-GM and Si5351C-B-GM. All three variants use the same pin assignments for XA/XB, VDD/VDDOx, SCL/SDA, OEB, CLK0–CLK7, and VC (or CLKIN on Si5351C). This allows direct PCB reuse across A/B/C versions when board layout accommodates unused pins.