Analog Devices Inc. AD9571ACPZLVD-RL

Overview

AD9571ACPZLVD-RL from Analog Devices is a fully integrated Ethernet clock generator IC with 10 clock outputs, featuring a dedicated integer-N PLL core optimized for GbE line cards. It delivers 156.25 MHz, 125 MHz/100 MHz (strappable), 33.33 MHz, and six 25 MHz outputs in LVPECL/LVDS or CMOS formats, with 0.17 ps rms jitter (1.875–20 MHz band at 156.25 MHz LVDS) and operation from a single 3.3 V supply.

For engineers reviewing the AD9571ACPZLVD-RL datasheet, AD9571ACPZLVD-RL pinout, AD9571ACPZLVD-RL application, or AD9571ACPZLVD-RL equivalent, this page provides verified technical context, exact pin functions, real-world jitter performance across output formats, confirmed package mapping to 40-lead 6 mm × 6 mm LFCSP, and two validated alternative clock generators for Ethernet timing systems.

Technical Context

The AD9571ACPZLVD-RL implements a fixed-ratio integer-N PLL with preprogrammed feedback and output dividers-no register programming required. Its PFD/CP/VCO architecture uses a low-noise 25 MHz crystal oscillator input and integrates third-order loop filtering, eliminating external components.

Output format selection (LVPECL or LVDS) is factory-configured; FREQSEL pin strapping selects between 100 MHz and 125 MHz on pins 19/20 and 21/22, while FORCE_LOW pin (37) disables the 33.33 MHz CMOS output to reduce crosstalk-induced jitter on adjacent differential pairs.

Key Specifications

Pinout & Package

AD9571ACPZLVD-RL is housed in a 40-lead, 6 mm × 6 mm lead frame chip scale package (LFCSP) with an exposed thermal/electrical paddle that must be soldered to PCB ground. Power supply (VS) and ground (GND) pins are distributed across multiple locations to minimize noise coupling; bypass capacitors (220 nF) are required on BYPASS1 (Pin 36) and BYPASS2 (Pin 14).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-output Ethernet clock generation applications.

Compared with Si5338A-B-GM and ICS8430I-01T, AD9571ACPZLVD-RL delivers deterministic, zero-configuration Ethernet timing with superior 156.25 MHz jitter (0.17 ps vs. ≥0.35 ps) and integrated 33.33 MHz support-making it optimal for high-reliability line cards where boot-time predictability and jitter margin are critical.

Availability

AD9571ACPZLVD-RL is available at Aetrix Electronics and suitable for Ethernet line cards, 10G router timing subsystems, and industrial switch fabric designs requiring stable component supply, long-term lifecycle assurance, and guaranteed traceable sourcing.

Supply support for AD9571ACPZLVD-RL 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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design centers worldwide and over 50 years of precision timing innovation.

The AD9571ACPZLVD-RL belongs to Analog Devices' Ethernet-optimized clock generator product line, engineered specifically to replace discrete PLL+VCO+divider solutions in carrier-grade networking equipment with single-chip, low-jitter, zero-configuration timing.

FAQ

What is the primary function of the AD9571ACPZLVD-RL in Ethernet systems?

The AD9571ACPZLVD-RL serves as a dedicated, fixed-ratio clock generator for Ethernet line cards, delivering precisely timed 156.25 MHz (XAUI), 125 MHz/100 MHz (GbE/PCIe), 33.33 MHz (CPU island), and six 25 MHz (PHY synchronization) clocks. Its integer-N PLL architecture, factory-programmed dividers, and integrated loop filter eliminate configuration overhead-making AD9571ACPZLVD-RL ideal for deterministic, high-reliability network infrastructure where boot-time clock stability is mandatory.

How does the FREQSEL pin affect output configuration on the AD9571ACPZLVD-RL?

The FREQSEL pin on AD9571ACPZLVD-RL selects between 100 MHz and 125 MHz output frequencies on pins 19/20 and 21/22. When pulled low, both differential pairs deliver 125 MHz; when pulled high, they deliver 100 MHz. An unconnected (NC) FREQSEL defaults to 125 MHz on Pin 19/20 and 100 MHz on Pin 21/22-enabling mixed-rate operation. This hardware strapping eliminates software dependencies, ensuring AD9571ACPZLVD-RL delivers correct frequencies immediately after power-up.

Why is the FORCE_LOW pin included on the AD9571ACPZLVD-RL?

The FORCE_LOW pin (Pin 37) on AD9571ACPZLVD-RL actively disables the 33.33 MHz CMOS output (Pin 23) when asserted high. This is critical because the proximity of Pin 23 to the 125 MHz differential pair (Pins 21/22) causes measurable jitter degradation when both are active simultaneously. By forcing Pin 23 low, AD9571ACPZLVD-RL preserves sub-0.41 ps rms jitter on the 125 MHz LVDS output-ensuring compliance with stringent GbE phase noise requirements without layout redesign.

What package type and thermal requirements apply to the AD9571ACPZLVD-RL?

AD9571ACPZLVD-RL uses a 40-lead 6 mm × 6 mm LFCSP with an exposed metal paddle that serves as both electrical ground and thermal path. The paddle must be soldered to a solid PCB ground plane to ensure functional integrity and thermal dissipation-θJA is rated at 27.5°C/W under JEDEC JESD51-7 conditions. Failure to connect the paddle results in degraded jitter performance and potential thermal shutdown, making proper AD9571ACPZLVD-RL mounting non-negotiable in production assemblies.

Can the AD9571ACPZLVD-RL operate with an external 25 MHz clock instead of a crystal?

Yes, AD9571ACPZLVD-RL supports both crystal (25 MHz fundamental mode, 14 pF load, ≤50 Ω ESR) and external clock inputs on the REFCLK pin (Pin 8). When using an external clock, REFSEL (Pin 9) must be tied high; when using the internal crystal oscillator, REFSEL is tied low. The input accepts 25 MHz ±100 ppm, 2.0 V/0.8 V logic thresholds, and exhibits only 2 pF input capacitance-ensuring minimal loading on upstream clock sources and maintaining AD9571ACPZLVD-RL's jitter performance regardless of reference choice.