Features and Benefits
Product DetailsThe AD9551 accepts one or two reference input signals to synthe-size one or two output signals. The AD9551 uses a fractional-N PLL that precisely translates the reference frequency to the desired output frequency. The input receivers and output drivers provide both single-ended and differential operation.
Reference conditioning and switchover circuitry internally synchronizes the two references so that if one reference fails, there is virtually no phase perturbation at the output.
The AD9551 uses an external crystal and an internal DCXO to provide for holdover operation. If both references fail, the device maintains a steady output signal.
The AD9551 provides pin-selectable, preset divider values for standard (and FEC adjusted) network frequencies. The pin-selectable frequencies include any combination of 15 possible input frequencies and 16 possible output frequencies. A SPI interface provides further flexibility by making it possible to program almost any rational input/output frequency ratio.
The AD9551 is a clock generator that employs fractional-N-based phase-locked loops (PLL) using sigma-delta (Σ-Δ) modulators (SDMs). The fractional frequency synthesis capability enables the device to meet the frequency and feature requirements for multiservice switch applications. The AD9551 precisely generates a wide range of standard frequencies when using any one of those same standard frequencies as a timing base (reference). The primary challenge of this function is the precise generation of the desired output frequency because even a slight output frequency error can cause problems for downstream clocking circuits in the form of bit or cycle slips. The requirement for exact frequency translation in such applications necessitates the use of a frac-tional-N-based PLL architecture with variable modulus.Applications
- Multiservice switches
- Multiservice routers
- Exact network clock frequency translation
- General-purpose frequency translation
Product Lifecycle Last Time Buy
All products in this family will be obsolete soon. Please contact ADI Sales or Distributors to arrange for final purchases and read our Obsolescence Information to review the time periods for placing final orders and receiving final shipments.
Evaluation Kits (1)
The AD9551 Revision D evaluation board is a compact, easy to use platform for evaluating all features of the AD9551 multiservice clock generator.
The AD9551 accepts one or two reference input signals to synthesize one or two output signals. The AD9551 uses a fractional-N PLL that precisely translates the reference frequency to the desired output frequency. The input receivers and output drivers provide both single-ended and differential operation. Reference conditioning and switchover circuitry internally synchronizes the two references so that if one reference fails, there is virtually no phase perturbation at the output.
The AD9551 uses an external crystal and an internal DCXO to provide for holdover operation. If both references fail, the device maintains a steady output signal. This may mislead you to believe that the PLL is locked and the board is configured properly. A simple test is to move the input REF A or REF B clock a few kilohertz and verify that the changes in output frequency track the input.
Features & Benefits
- Simple power connection using USB connection and on-board LDO voltage regulators
- LDOs are easily bypassed for power measurements
- AC-coupled differential LVPECL SMA connectors
- SMA connectors for
2 reference inputs
2 PLL lock detect outputs
- Microsoft Windows®–based evaluation software with simple graphical user interface
- On-board PLL loop filter
- Easy access to digital I/O and diagnostic signals via I/O header
- Status LEDs for diagnostic signals
- USB computer interface
- Dip switch configurable for manual operation
- Software calculator provides flexibility, allowing programming almost any rational input/output frequency ratio
Tools & Simulations
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.