CDCR81DBQRG4

Application Specific Clock/Timing Overview

The CDCR81DBQRG4 is a Direct Rambus clock generator designed for memory subsystems supporting up to 600-MHz data transfer rates. It operates from a single 3.3-V supply and consumes approximately 120 mW at 300 MHz. The device features an internal phase-locked loop (PLL) with no external components required, accepting reference clocks between 33 MHz and 100 MHz. It generates BUSCLK frequencies ranging from 267 MHz to 400 MHz using selectable multiply ratios. Packaged in a 24-pin shrink small-outline package (DBQ), it supports spread spectrum clocking tracking and includes multiple power operating modes.

Application Specific Clock/Timing Feature Summary

• Internal PLL requires no external components for frequency multiplication
• Supports independent channel clocking and spread spectrum tracking
• Three power operating modes including power-down and clock stop states
• Phase alignment logic minimizes skew between PCLK/M and SYNCLK/N

Application Specific Clock/Timing Applications

• Direct Rambus memory subsystems on desktop motherboards
• Workstation and server memory architectures
• Mobile PC motherboard designs requiring low power consumption

Application Specific Clock/Timing Procurement Notes

Verify the component meets the specific voltage and temperature requirements for the target application. Confirm that the DBQ package dimensions align with the PCB footprint design. Ensure the reference clock input specifications match the system's REFCLK source characteristics before integration.

Application Specific Clock/Timing Selection Notes

Select this component when designing Direct Rambus systems requiring synchronization between the Rambus channel and an external processor clock. It is suitable for applications needing clock multiplication ratios of 4, 6, or 8/3 within the 33 MHz to 100 MHz input range. Consider its power modes if mobile or power-sensitive designs are prioritized.

Application Specific Clock/Timing Part Context

The CDCR81 is part of Texas Instruments' Direct Rambus Clock Generator family. It is specifically engineered to support Rambus Revision 1.0 specifications up to 300 MHz. The device is designed to work in conjunction with TI’s 133-MHz clock synthesizers such as the CDC925, CDC924, CDC922, and CDC921.

Application Specific Clock/Timing Replacement Considerations

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