Analog Devices Inc. AD9571ACPZLVD-R7

Overview

AD9571ACPZLVD-R7 from Analog Devices is a fully integrated Ethernet clock generator IC with 10 dedicated clock outputs, featuring a low-jitter integer-N PLL core optimized for GbE line cards. It delivers 156.25 MHz, dual 100/125 MHz, six 25 MHz, and one 33.33 MHz outputs in LVPECL/LVDS or CMOS formats, supporting IEEE 802.3ae XAUI and 10GBASE-R timing requirements.

For engineers reviewing the AD9571ACPZLVD-R7 datasheet, AD9571ACPZLVD-R7 pinout, AD9571ACPZLVD-R7 application, or AD9571ACPZLVD-R7 equivalent, this page provides verified jitter specs (0.17 ps rms @ 156.25 MHz, 1.875–20 MHz), output format selection (LVDS/LVPECL), strappable frequency configuration, integrated loop filter, and thermal design guidance for 6 mm × 6 mm LFCSP packaging.

Technical Context

The AD9571ACPZLVD-R7 implements a fixed-ratio integer-N PLL architecture with a low-noise PFD, precision charge pump, and VCO optimized for 25 MHz crystal input. Its preprogrammed dividers lock to 156.25 MHz, 125 MHz, 100 MHz, or 33.33 MHz without external programming - all configured via FREQSEL, REFSEL, and FORCE_LOW strapping pins.

It integrates three independent power domains (GbE PLL/VCO, FC PLL/VCO, output buffers), on-chip LDO bypassing (BYPASS1/BYPASS2), and a factory-configured LVDS output interface. The 40-lead LFCSP exposes a grounded thermal paddle essential for thermal management at 0.48 W (LVDS) or 0.69 W (LVPECL) dissipation.

Key Specifications

Pinout & Package

AD9571ACPZLVD-R7 uses a 40-lead LFCSP (6 mm × 6 mm) with exposed thermal paddle that must be soldered to PCB ground. Power supply (VS) and ground (GND) pins are distributed across 14 locations to minimize noise coupling; bypass capacitors (220 nF) 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 generator applications.

Compared with IDT8T49N242A and Si5338A-B-GM, AD9571ACPZLVD-R7 offers lowest jitter (0.17 ps rms) and zero-config operation for Ethernet-specific frequencies, trading programmability for deterministic performance and reduced BOM complexity.

Availability

AD9571ACPZLVD-R7 is available at Aetrix Electronics and suitable for Ethernet line cards, 10GBASE-R switches, and XAUI-based optical modules requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for AD9571ACPZLVD-R7 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 deep expertise in precision timing and RF technologies.

The AD9571ACPZLVD-R7 belongs to Analog Devices' Ethernet-optimized clock generator product line, designed specifically to replace discrete PLL + fanout solutions in carrier-grade networking hardware with single-chip, low-jitter, thermally robust integration.

FAQ

What is the maximum allowable jitter for AD9571ACPZLVD-R7 at 156.25 MHz in LVDS mode?

The AD9571ACPZLVD-R7 achieves 0.17 ps rms jitter (1.875–20 MHz integration bandwidth) at 156.25 MHz LVDS output under typical conditions (3.3 V, 25°C). This value is measured differentially across Pins 17 and 18 with all other outputs active except 33.33 MHz, meeting IEEE 802.3ae XAUI jitter limits without external cleanup. The AD9571ACPZLVD-R7 maintains this performance across its full operating temperature range (−40°C to +85°C) with proper PCB layout and decoupling.

Can AD9571ACPZLVD-R7 generate both 100 MHz and 125 MHz simultaneously?

No - the AD9571ACPZLVD-R7 cannot generate 100 MHz and 125 MHz simultaneously. Its two 100M/125M LVDS output pairs (Pins 19/20 and 21/22) are strapping-controlled: FREQSEL (Pin 27) selects either 100 MHz (logic high) or 125 MHz (logic low) for both pairs. The "NC" state in Table 15 allows one pair to output 125 MHz while the other outputs 100 MHz, but this is not supported in the AD9571ACPZLVD-R7's factory configuration and violates the device's specified operation.

How does FORCE_LOW (Pin 37) affect AD9571ACPZLVD-R7 jitter performance?

Asserting FORCE_LOW (Pin 37) forces the 33.33 MHz CMOS output (Pin 23) to logic low, eliminating switching noise that couples into adjacent 125 MHz LVDS outputs (Pins 21/22). When FREQSEL = 0 (125 MHz mode), enabling the 33.33 MHz output increases 125 MHz jitter by up to 1.9 ps rms (Table 3). Using FORCE_LOW restores baseline jitter (0.25 ps rms) - a critical design step for 125 MHz applications like 10GBASE-R.

Is AD9571ACPZLVD-R7 compatible with 25 MHz fundamental-mode crystals only?

Yes - the AD9571ACPZLVD-R7 is designed exclusively for 25 MHz fundamental-mode crystals connected to Pins 6 and 7. The oscillator circuit specifies 14 pF load capacitance, 50 Ω ESR, and ±30 ppm stability. Using overtone crystals, TCXOs, or non-25 MHz references violates the device's electrical specifications and invalidates jitter and phase noise guarantees stated in the datasheet for AD9571ACPZLVD-R7.

What is the recommended PCB layout practice for the exposed paddle on AD9571ACPZLVD-R7?

The exposed thermal paddle on AD9571ACPZLVD-R7 must be soldered to a solid PCB ground plane using ≥4 thermal vias (0.3 mm diameter) placed within the paddle area. This connection serves both electrical (reference ground) and thermal (27.5°C/W θJA) functions. Failure to ground the paddle causes functional failure - the AD9571ACPZLVD-R7 will not lock or output valid clocks. Analog Devices' evaluation board layout (UG-123) provides the verified via pattern and copper pour geometry for AD9571ACPZLVD-R7.