AD9551BCPZ

Overview

The AD9551BCPZ is a multiservice clock generator by Analog Devices Inc. It translates between standard network rates using a fractional-N PLL architecture with sigma-delta modulators. The device accepts dual reference inputs and provides two independent clock outputs, supporting frequencies from 10 MHz to 900 MHz. Input frequencies range from 19.44 MHz to 806 MHz. Key features include pin-programmable preset divider values for standard rates, SPI programmability for arbitrary rational ratios, on-chip VCO, holdover operation, and hitless switchover. It operates on a single 3.3 V supply and supports LVPECL, LVDS, or CMOS output logic levels.

Feature Summary

• Dual reference inputs and dual clock outputs with automatic synchronization and hitless switchover
• Fractional-N PLL architecture with sigma-delta modulators for precise frequency translation
• Pin-selectable preset divider values for standard network rates (15 input, 16 output combinations)
• SPI-compatible 3-wire programming interface for arbitrary rational rate translation
• Supports holdover operation using an external crystal and internal DCXO

Applications

• Multiservice switches
• Multiservice routers
• Exact network clock frequency translation
• General-purpose frequency translation

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current data sheet to confirm package type and temperature range. Ensure the external crystal specifications match the required operating mode (normal vs. 19.44 MHz). Confirm that the application circuit includes the necessary decoupling capacitors for the LDO pins as specified in the datasheet.

Selection Notes

Select the AD9551BCPZ when precise translation between disparate standard network frequencies is required. Use pin-programming for fixed standard rates to simplify design; use the SPI interface for flexible, non-standard ratios. Ensure the external crystal frequency aligns with the chosen operating mode (26 MHz for normal, other ranges for 19.44 MHz mode). Verify output driver compatibility (LVPECL/LVDS/CMOS) with downstream components.

Part Context

The AD9551 is part of Analog Devices' multiservice clock generator family, designed for telecommunications infrastructure. It addresses the need for exact frequency synthesis in SONET/SDH and Ethernet applications. The BC suffix typically denotes the industrial temperature range (-40°C to +85°C) and the LFCSP package variant, consistent with other ADI parts in this series.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material.