Skyworks Solutions Inc. SI52258A-D01AMR

Overview

SI52258A-D01AMR from Skyworks Solutions is an 8-output automotive-grade PCIe Gen1–5 clock generator delivering eight 100 MHz HCSL differential clocks with internal 85 Ω or 100 Ω line matching, 0.025 ps RMS jitter (Gen5), and –40 to +105 °C operation for ADAS ECU and radar sensor timing.

For engineers reviewing the SI52258A-D01AMR datasheet, SI52258A-D01AMR pinout, SI52258A-D01AMR application, or SI52258A-D01AMR equivalent, this page provides verified technical context, PCIe-compliant jitter specs, hardware-controlled output enable/impedance/spread-spectrum functions, and automotive-qualified thermal performance.

Technical Context

The SI52258A-D01AMR integrates a low-jitter PLL with triangular spread spectrum modulation (0.25% or 0.5% down-spread at 31.5 kHz) and supports both common clock and SRIS PCIe architectures. It accepts a 25 MHz parallel-resonant crystal input and generates eight synchronized 100 MHz HCSL outputs with per-output enable control and loss-of-signal (LOS) monitoring.

Each output driver features selectable internal termination (85 Ω or 100 Ω via IMP_SEL), independent VDDO supply pins (1.8–3.3 V), and open-drain LOS reporting. The device uses a single core supply (VDDA/VDD_DIG/VDD_XTAL = 1.8–3.3 V) and meets AEC-Q100 Grade 2 requirements.

Key Specifications

Pinout & Package

SI52258A-D01AMR is housed in a 6 × 6 mm, 40-pin QFN package with exposed thermal pad (GND PAD, Pin 41). The package supports reflow soldering per JEDEC J-STD-020 and provides θJA = 23.1 °C/W (still air) for automotive thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI52258A-D01AMR, the SI52258A-D01AM offers identical electrical performance but lacks tape-and-reel packaging for high-volume manufacturing, while the Si52254A-D01AMR reduces output count and package size at the expense of fanout capability - making it optimal for scaled-down automotive timing nodes.

Availability

SI52258A-D01AMR is available at Aetrix Electronics and suitable for infotainment systems, ADAS ECU timing, and radar sensor modules requiring stable component supply across automotive production lifecycles.

Supply support for SI52258A-D01AMR 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 leader in analog semiconductors, specializing in RF, timing, and connectivity solutions for automotive, infrastructure, and mobile markets.

The Si5225x family was designed specifically to meet stringent PCIe Gen1–5 jitter, automotive temperature, and EMI requirements - targeting high-reliability timing in ADAS, infotainment, and sensor fusion systems.

FAQ

What is the primary function of the SI52258A-D01AMR in a PCIe-based automotive system?

The SI52258A-D01AMR serves as an 8-output PCIe Gen1–5 clock generator, providing eight synchronized 100 MHz HCSL clocks to multiple endpoints such as radar SoCs, ADAS ECUs, and infotainment processors. Its low 0.025 ps RMS jitter (Gen5), automotive temperature range (–40 to +105 °C), and hardware-controlled features make it ideal for deterministic timing in safety-critical vehicle systems. SI52258A-D01AMR replaces discrete oscillators and fanout buffers with a single AEC-Q100 qualified IC.

Does the SI52258A-D01AMR require an external crystal or can it accept a clock input?

The SI52258A-D01AMR is designed to operate from a 25 MHz parallel-resonant crystal connected to XA/XB pins; it does not support external single-ended clock input per the datasheet. The crystal interface presents 2.5 pF input capacitance and requires external load capacitors matched to the crystal's specified CL. SI52258A-D01AMR relies on its internal oscillator circuit - no alternative clock input path is defined or characterized.

How is impedance selection implemented on the SI52258A-D01AMR, and when is it sampled?

Impedance selection on the SI52258A-D01AMR is controlled by the IMP_SEL pin (Pin 19), which configures all eight HCSL outputs to either 85 Ω (IMP_SEL = high) or 100 Ω (IMP_SEL = low) internal termination. This setting is latched only at power-up and cannot be changed dynamically during operation. SI52258A-D01AMR uses this static configuration to match common PCB trace impedances without requiring external resistors or layout redesign.

What is the role of the LOS pin on the SI52258A-D01AMR, and how must it be interfaced?

The LOS (Loss of Signal) pin (Pin 10) on the SI52258A-D01AMR is an open-drain, active-low output that asserts logic low when the 25 MHz crystal input frequency drops below ~10 MHz - indicating crystal failure or disconnection. It requires an external pull-up resistor (1–10 kΩ) to VDD or another logic supply. SI52258A-D01AMR uses LOS for real-time fault detection in automotive safety monitors, enabling system-level diagnostics without additional sensing circuitry.

Can spread spectrum be enabled independently per output on the SI52258A-D01AMR?

No - spread spectrum modulation on the SI52258A-D01AMR is globally controlled by the SSC_EN pin (Pin 20); it cannot be enabled or disabled per individual output. When SSC_EN is high, triangular spread spectrum (0.25% or 0.5% down-spread at ~31.5 kHz) is applied to all eight outputs simultaneously to reduce EMI across the entire clock tree. SI52258A-D01AMR does not support per-output SSC enable/disable or frequency deviation tuning.