Analog Devices Inc. ADN2805ACPZ-500RL7

Overview

ADN2805ACPZ-500RL7 from Analog Devices is a 1.25 Gbps clock and data recovery (CDR) IC with integrated quantizer, delay-locked loop (DLL), and phase-locked loop (PLL) architecture. It locks autonomously to NRZ serial data without external reference clock, delivers LVDS clock/data outputs, and meets all SONET jitter requirements including 0.003 UI_rms jitter generation and 0.749 UI_p-p jitter tolerance for GbE applications.

For engineers reviewing the ADN2805ACPZ-500RL7 datasheet, ADN2805ACPZ-500RL7 pinout, ADN2805ACPZ-500RL7 application, or ADN2805ACPZ-500RL7 equivalent, key selection criteria include its 32-pin LFCSP package, I²C-configurable lock modes, loss-of-lock indicator with 200 µs response, and dual-loop jitter accommodation supporting GbE line card regeneration and optical receiver front-end timing recovery.

Technical Context

The ADN2805ACPZ-500RL7 implements a patented dual-loop architecture: a high-speed DLL using a voltage-controlled phase shifter tracks high-frequency jitter, while a separate PLL with VCO handles low-frequency components. A third frequency-locked loop (FLL) sets coarse VCO tuning by comparing VCO and input data frequencies.

Its jitter transfer function is second-order low-pass with no zero in the closed-loop transfer-eliminating jitter peaking-and achieves 0.03 dB max jitter peaking. The circuit supports both autonomous lock-to-data mode (1.5 ms acquisition) and optional lock-to-REFCLK mode (20 ms) with 10–160 MHz reference input and 100 ppm accuracy requirement.

Key Specifications

Pinout & Package

ADN2805ACPZ-500RL7 uses a 5 mm × 5 mm, 32-lead lead-frame chip-scale package (LFCSP) with exposed thermal pad soldered to ground. The package is Pb-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock and data recovery applications.

Compared with MAX3875EEE+ and LMK03806RHAT, the ADN2805ACPZ-500RL7 uniquely combines autonomous lock-to-data operation, I²C configurability, and SONET-compliant jitter performance in a compact LFCSP-making it optimal for GbE line cards where reference clock absence and jitter-critical regeneration are primary constraints.

Availability

ADN2805ACPZ-500RL7 is available at Aetrix Electronics and suitable for GbE line card regeneration, optical media converter timing, SONET/SDH receiver front-ends, and test equipment signal integrity applications requiring stable component supply across production lifecycles.

Supply support for ADN2805ACPZ-500RL7 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 semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision signal conditioning and conversion.

The ADN2805ACPZ-500RL7 belongs to Analog Devices' clock and data recovery product line, engineered specifically for telecom and datacom applications demanding ultra-low jitter, autonomous lock, and SONET/SDH compliance at 1.25 Gbps.

FAQ

What is the primary function of the ADN2805ACPZ-500RL7 in a GbE line card?

The ADN2805ACPZ-500RL7 serves as a clock and data recovery IC that retimes and cleans 1.25 Gbps NRZ serial data streams. It extracts a low-jitter clock and reconstructs the data signal, meeting SONET jitter specifications for use in GbE line cards where signal integrity after fiber transmission must be restored. Its autonomous lock capability eliminates dependency on external reference clocks in the ADN2805ACPZ-500RL7 design.

Does the ADN2805ACPZ-500RL7 require an external reference clock to operate?

No, the ADN2805ACPZ-500RL7 does not require an external reference clock for basic operation. It features autonomous frequency acquisition and phase lock to 1.25 Gbps NRZ data using its internal FLL/PLL/DLL architecture. An optional REFCLK input (10–160 MHz) is supported via pins REFCLKP/REFCLKN for assisted lock mode, but it is not mandatory-the ADN2805ACPZ-500RL7 functions fully without it.

How does the LOL pin on the ADN2805ACPZ-500RL7 behave during normal operation?

The LOL (Loss-of-Lock) pin on the ADN2805ACPZ-500RL7 is an active-high LVTTL output that asserts when the VCO frequency deviates more than ±1000 ppm from nominal and deasserts when within ±250 ppm. Its 200 µs response time enables rapid fault detection. In static LOL mode (configurable via I²C register CTRLB[7]), the pin latches the first loss-of-lock event until manually reset-providing persistent status for system diagnostics in the ADN2805ACPZ-500RL7.

What package type and thermal characteristics apply to the ADN2805ACPZ-500RL7?

The ADN2805ACPZ-500RL7 uses a 5 mm × 5 mm, 32-lead LFCSP package with exposed thermal pad connected to ground. Its thermal resistance is θ_JA = 28 °C/W on a 4-layer board with the exposed pad soldered to VEE. This enables reliable operation at full 390 mW power dissipation within the −40°C to +85°C ambient range specified for the ADN2805ACPZ-500RL7.

Can the ADN2805ACPZ-500RL7 be used for data rates other than 1.25 Gbps?

No, the ADN2805ACPZ-500RL7 is a fixed-rate CDR optimized exclusively for 1.25 Gbps NRZ data. Its internal loop filters, VCO tuning range, and jitter specifications (e.g., 0.749 UI_p-p tolerance at 637 kHz) are calibrated for GbE/SONET OC-24 compliance. It does not support multi-rate operation or user-programmable data rates-the ADN2805ACPZ-500RL7 is not configurable for 1.0 Gbps, 2.5 Gbps, or other speeds.