Skyworks Solutions Inc. SI52111-B5-GT

Overview

SI52111-B5-GT from Skyworks Solutions is a PCIe Gen 3 single-output clock generator delivering 100 MHz HCSL differential clock compliant with PCIe Gen 1–4 common clock and Gen 3 SRNS specifications. It accepts a 25 MHz crystal or clock input, operates from a 3.3 V supply, and targets embedded networking and storage systems requiring low-jitter timing.

For engineers reviewing the SI52111-B5-GT datasheet, SI52111-B5-GT pinout, SI52111-B5-GT application, or SI52111-B5-GT equivalent, key selection criteria include PCIe Gen 3/4 phase jitter (≤1.0 ps RMS), 8-pin TSSOP package compatibility, absence of spread-spectrum capability, and -40 to +85 °C extended temperature operation.

Technical Context

The SI52111-B5-GT integrates a PLL-based frequency synthesis architecture optimized for PCIe clock distribution, with fixed 4× multiplication (25 MHz → 100 MHz) and no programmability. Its output buffer is a low-power HCSL driver with 0.7 V differential swing, 45–55% duty cycle, and <70 ps cycle-to-cycle jitter.

Unlike the B6 variant, the SI52111-B5-GT omits triangular spread-spectrum modulation-eliminating EMI reduction but ensuring deterministic timing behavior. It supports both crystal (XIN/XOUT) and external clock (CLKIN) reference modes, with internal load capacitance compensation and no external termination resistors required.

Key Specifications

Pinout & Package

SI52111-B5-GT uses an 8-pin TSSOP package (3.0 × 4.4 mm footprint, 0.65 mm pitch), optimized for cost-sensitive, high-volume consumer and embedded applications. The package is RoHS6-compliant and Pb-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI52111-B6-GT, SI52111-B5-GT trades EMI suppression for tighter jitter control and deterministic behavior; compared with ICS8430M-01T, it delivers HCSL-native drive, lower power, and smaller TSSOP packaging-reducing BOM count and layout complexity in new designs.

Availability

SI52111-B5-GT is available at Aetrix Electronics and suitable for network attached storage, wireless access points, and routers requiring stable component supply, industrial temperature support, and PCIe Gen 3–4 timing compliance.

Supply support for SI52111-B5-GT 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 power management ICs.

The Si52111 family is designed specifically for PCIe-compliant clock generation in space- and power-constrained embedded systems, emphasizing low jitter, small footprint, and seamless integration with modern SoCs.

FAQ

What is the primary function of the SI52111-B5-GT in a PCIe system?

The SI52111-B5-GT serves as a dedicated single-output PCIe reference clock generator, producing a 100 MHz HCSL differential signal compliant with PCIe Gen 1–4 common clock and Gen 3 SRNS specifications. It replaces discrete crystal oscillators and buffer chains, reducing component count while guaranteeing sub-1 ps RMS jitter performance required for stable 8 GT/s link operation in the SI52111-B5-GT.

Does the SI52111-B5-GT support spread-spectrum clocking?

No, the SI52111-B5-GT does not support spread-spectrum clocking. This feature is exclusive to the SI52111-B6 variant (e.g., SI52111-B6-GT), which provides 0.5% down-spread modulation at 31.5 kHz. The SI52111-B5-GT delivers deterministic timing with no intentional frequency deviation-ideal for applications where jitter predictability is critical.

What package type and pin count does the SI52111-B5-GT use?

The SI52111-B5-GT uses an 8-pin TSSOP package (3.0 × 4.4 mm body, 0.65 mm pitch), as confirmed in the Skyworks ordering guide and package drawings. It has two no-connect (NC) pins (pins 7 and 8), one VDD, one VSS, one XIN/CLKIN, one XOUT, and two DIFF1 output pins (pins 5 and 6) forming a differential pair.

Can the SI52111-B5-GT accept both crystal and external clock inputs?

Yes, the SI52111-B5-GT supports dual-input mode via its XIN/CLKIN pin: it can drive a 25 MHz parallel-resonant AT-cut crystal (with XOUT used as oscillator output) or accept a 25 MHz 3.3 V CMOS clock signal. When using external clock, XOUT must be left floating. This flexibility simplifies design reuse across crystal- and clock-driven platforms for the SI52111-B5-GT.

What is the maximum allowable operating temperature for the SI52111-B5-GT?

The SI52111-B5-GT is rated for extended temperature operation from –40 °C to +85 °C, as specified in Table 4 (Thermal Conditions) of the Skyworks datasheet. This range supports deployment in fanless or thermally challenging environments such as enclosed routers, NAS enclosures, and industrial edge gateways where ambient temperatures exceed commercial-grade limits.