CDCU877GQLR Equivalent & Substitute Parts

Part Overview

The CDCU877GQLR is a Memory DDR2 Clock Buffer/Driver IC manufactured by Texas Instruments, designed for high-speed clock distribution in DDR2 memory applications. This device features a PLL-based architecture with 1:10 input-to-output ratio and operates at frequencies up to 400MHz with 1.8V supply voltage. The part is classified as Obsolete, necessitating identification of functionally equivalent alternatives for ongoing system support and new designs requiring similar clock distribution capabilities.

Substiute Parts

CDCU877GQLR

Texas InstrumentsIn Stock: 1923CDCU877GQLR Datasheet

Current PartRFQ

98ULPA877AHT

Renesas Electronics CorporationIn Stock: 83598ULPA877AHT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CDCU877GQLR is determined by the following critical parameters that must be maintained or exceeded:

• PLL Architecture: Presence of integrated Phase-Locked Loop for clock multiplication
• Input-to-Output Ratio: 1:10 multiplication capability
• Differential Signaling: Both input and output must support differential SSTL-18 signaling
• Frequency Performance: Maximum operating frequency must meet or exceed 400MHz
• Supply Voltage Compatibility: 1.7V to 1.9V operating range
• Package Type: Surface mount BGA configuration suitable for DDR2 memory applications
• Single Circuit Configuration: One independent clock driver circuit

The 98ULPA877AHT from Renesas Electronics Corporation qualifies as a substitute based on matching these core functional parameters while maintaining DDR2 memory clock distribution capability.

Parameter Comparison

Engineering Selection Recommendations

The 98ULPA877AHT serves as a functional substitute for the obsolete CDCU877GQLR in DDR2 clock distribution applications. Key considerations for selection:

Advantages of the Substitute:

• Active product status ensures ongoing availability and manufacturing support
• Maximum frequency specification of 410MHz exceeds the original 400MHz requirement
• Identical supply voltage range and 1:10 multiplication ratio maintain circuit compatibility
• Differential SSTL-18 input and output signaling preserved

Design Considerations:

• Operating temperature range is narrower (0°C to 70°C versus -40°C to 85°C); applications requiring extended temperature operation must evaluate thermal requirements
• Package footprint differs: 52-VFBGA versus 56-VFBGA; PCB layout modifications may be required
• RoHS compliance status differs; regulatory requirements must be assessed for the target application
• Moisture sensitivity level increases from MSL 2 to MSL 3; storage and handling procedures must be adjusted accordingly

Frequently Asked Questions (FAQ)

Q: Can the 98ULPA877AHT directly replace the CDCU877GQLR without PCB modifications?

A: The substitute part maintains functional compatibility through matching PLL architecture, 1:10 ratio, differential SSTL-18 signaling, and supply voltage specifications. However, package differences (52-VFBGA versus 56-VFBGA) require PCB layout evaluation and potential footprint adjustment.

Q: What is the impact of the narrower operating temperature range on the 98ULPA877AHT?

A: The substitute operates from 0°C to 70°C compared to the original -40°C to 85°C range. Applications requiring operation below 0°C or above 70°C must implement external thermal management or select alternative parts with extended temperature specifications.

Q: How does the change in Moisture Sensitivity Level affect component handling?

A: The 98ULPA877AHT has MSL 3 (168 hours) versus MSL 2 (1 year) for the original part. This requires stricter moisture control during storage and shorter shelf life after bag opening. Baking procedures may be necessary before reflow soldering if the component has exceeded moisture exposure limits.

Q: Are there electrical performance differences between these parts?

A: Both parts maintain identical supply voltage (1.7V to 1.9V), input-to-output ratio (1:10), and differential signaling architecture. The substitute provides 10MHz additional frequency headroom (410MHz versus 400MHz), which is within typical design margins for DDR2 applications.

Q: What compliance differences should be considered?

A: The original CDCU877GQLR is ROHS3 compliant, while the 98ULPA877AHT is RoHS non-compliant. Applications subject to RoHS regulations must evaluate whether this substitution meets regulatory requirements or if alternative compliant parts must be sourced.