Analog Devices Inc. AD809BR-REEL7

Overview

AD809BR-REEL7 from Analog Devices is a 155.52 MHz frequency synthesizer IC that generates ECL/PECL-compatible clock outputs from 19.44 MHz or 9.72 MHz TTL/CMOS/PECL reference inputs. It integrates a low-jitter VCO, phase-frequency detector, loop filter, and input multiplexer in a single 16-pin SOIC package, and is used to generate transmit bit clocks in SONET/SDH optical line cards.

For engineers reviewing the AD809BR-REEL7 datasheet, AD809BR-REEL7 pinout, AD809BR-REEL7 application, or AD809BR-REEL7 equivalent, key selection criteria include its ×8/×16 synthesis capability, 2.0° RMS output jitter, ±40°C to +85°C operating range, single +5 V or –5.2 V supply operation, and PECL/TTL/CMOS input compatibility.

Technical Context

The AD809BR-REEL7 implements a second-order PLL architecture with auto-selecting input multiplexer (TTL/CMOSIN vs. PECLIN/CLKIN), programmable divide-by-8 or divide-by-16, and on-chip VCO locked to reference inputs. Its loop dynamics are externally adjustable via damping capacitors CF1 and CF2 (e.g., 22 nF yields ζ = 10).

It delivers differential 155.52 MHz PECL outputs (CLKOUT/CLKOUTN) with 1.1–1.5 ns rise/fall times, 46–62% symmetry, and guaranteed low-frequency drift behavior (−20% output frequency shift under loss-of-signal). Input tracking ranges are 19.42–19.46 MHz (×8) and 9.71–9.73 MHz (×16).

Key Specifications

Pinout & Package

AD809BR-REEL7 is housed in a 16-pin narrow-body SOIC (R-16A) package, 150 mil width, with θ_JA = 110°C/W. Pin 1 identifier is marked by a beveled corner; pins are numbered counterclockwise.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar frequency synthesizer applications.

Compared with AD9510BCPZ-REEL7 and ICS8430MILF-T, the AD809BR-REEL7 offers unique value in SONET/SDH systems requiring guaranteed −20% loss-of-signal drift, PECL-level 155.52 MHz output, and hardware-selectable reference inputs - all in a cost-optimized, single-function SOIC package.

Availability

AD809BR-REEL7 is available at Aetrix Electronics and suitable for SONET line card design, SDH transport node development, and Fiber-in-the-Loop terminal manufacturing requiring stable component supply across extended temperature and long production lifecycles.

Supply support for AD809BR-REEL7 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 is a global leader in high-performance analog, mixed-signal, and DSP technologies, serving precision instrumentation, communications, and industrial markets since 1965.

The AD809BR-REEL7 belongs to Analog Devices' timing and clock generation product line, engineered specifically for telecom infrastructure applications demanding deterministic jitter performance and robust reference switching in SONET/SDH systems.

FAQ

What is the primary function of the AD809BR-REEL7?

The AD809BR-REEL7 is a dedicated 155.52 MHz frequency synthesizer IC that locks to either 19.44 MHz (×8) or 9.72 MHz (×16) reference inputs and produces low-jitter differential PECL outputs. Its core function is generating compliant transmit bit clocks for SONET OC-3 and SDH STM-1 optical interfaces, with built-in fail-safe behavior and hardware-selectable reference paths.

Does the AD809BR-REEL7 support both TTL/CMOS and PECL reference inputs?

Yes, the AD809BR-REEL7 supports both input types via an internal multiplexer controlled by the MUX pin. When MUX = logic "0", the device selects the single-ended TTL/CMOSIN input (Pin 10); when MUX = logic "1", it selects the differential PECL reference on Pins 12/13. The AD809BR-REEL7 automatically senses common-mode levels to validate input type, enabling mixed-signal timing architectures without external level-shifting.

What is the significance of the −20% output frequency drift specification for the AD809BR-REEL7?

The AD809BR-REEL7 is designed to drift low by approximately 20% in output frequency (to ~124 MHz) when the reference input is lost. This intentional, guaranteed behavior prevents downstream PLLs from locking to spurious or unstable frequencies during signal interruption. It is a safety-critical feature for telecom systems where uncontrolled clock behavior could cause frame loss or network synchronization failure - a design attribute explicitly verified in the AD809BR-REEL7 datasheet.

Can the AD809BR-REEL7 operate from a +3.3 V supply?

No, the AD809BR-REEL7 does not support +3.3 V operation. Its absolute maximum supply rating is +12 V, but the specified operating range is +4.5 V to +5.5 V for positive supply or –5.2 V for negative supply. Operation outside this range - including +3.3 V - is not characterized, and attempting it may result in undefined behavior, failure to lock, or damage. The AD809BR-REEL7 must be powered per its published supply conditions to ensure correct 155.52 MHz synthesis and jitter performance.

How is loop stability adjusted on the AD809BR-REEL7?

Loop stability on the AD809BR-REEL7 is adjusted using external ceramic capacitors connected to Pins 7 (CF1) and 8 (CF2). These set the damping factor (ζ) of the second-order PLL: for example, a 22 nF capacitor yields ζ = 10, minimizing jitter transfer peaking. The AD809BR-REEL7 datasheet provides measured peaking values (0.02 dB) and bandwidth (200 kHz) for this configuration, allowing designers to tune lock time and input-jitter rejection without modifying the IC itself.