CDCU877BZQLT Equivalent & Substitute Parts

Part Overview

The CDCU877BZQLT is a DDR2 memory clock buffer/driver IC manufactured by Texas Instruments, designed for high-speed clock distribution in memory subsystems. This device features a 1:10 input-to-output ratio with differential signaling on both input and output, operating at frequencies up to 400MHz with 1.8V supply voltage compatibility.

The CDCU877BZQLT is classified as obsolete. Identifying suitable substitute parts is necessary for ongoing system support, design updates, and procurement continuity when original inventory becomes unavailable.

Substiute Parts

CDCU877BZQLT

Texas InstrumentsIn Stock: 2159CDCU877BZQLT Datasheet

Current PartRFQ

98ULPA877AHT

Renesas Electronics CorporationIn Stock: 83598ULPA877AHT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the CDCU877BZQLT is determined by the following critical parameters:

• Package compatibility: 52-VFBGA form factor with matching pinout
• Frequency specification: Maximum operating frequency of 400MHz or higher
• Supply voltage range: 1.7V ~ 1.9V compatibility
• Signal integrity: Differential input and output capability with SSTL-18 or compatible signaling
• Functional architecture: 1:10 clock multiplication ratio with single circuit configuration
• Thermal operating range: Support for -40°C ~ 85°C or subset thereof

The 98ULPA877AHT from Renesas Electronics Corporation meets these substitution criteria with compatible electrical specifications and package dimensions, though with noted differences in product status and compliance certifications.

Parameter Comparison

Engineering Selection Recommendations

The 98ULPA877AHT qualifies as a functional substitute for the CDCU877BZQLT based on matching electrical specifications, package form factor, and clock distribution architecture. Both devices support identical supply voltage ranges, differential signaling protocols, and 1:10 clock multiplication ratios required for DDR2 memory subsystems.

Key considerations for selection:

Product Status: The 98ULPA877AHT maintains active production status, ensuring long-term availability and supply chain continuity compared to the obsolete CDCU877BZQLT.

Compliance Differences: The CDCU877BZQLT is ROHS3 compliant with MSL 2 rating, while the 98ULPA877AHT is RoHS non-compliant with MSL 3 rating. Applications subject to RoHS requirements or requiring extended shelf life storage must account for these differences.

Operating Temperature Range: The CDCU877BZQLT supports -40°C ~ 85°C operation, while the 98ULPA877AHT operates within 0°C ~ 70°C. Systems requiring extended low-temperature operation below 0°C cannot use the Renesas substitute without thermal derating analysis.

Frequency Margin: The 98ULPA877AHT provides 10MHz additional frequency headroom (410MHz vs. 400MHz), offering improved performance margin for high-speed clock distribution applications.

Frequently Asked Questions (FAQ)

Q: Can the 98ULPA877AHT directly replace the CDCU877BZQLT in existing designs?

A: Electrical and functional compatibility is confirmed for DDR2 clock distribution applications. Physical package dimensions are equivalent (52-VFBGA, 7x4.5mm). However, thermal operating range and compliance certifications differ. Designs operating below 0°C or requiring ROHS3 compliance must evaluate these differences before substitution.

Q: What are the key electrical parameters that determine substitution compatibility?

A: Supply voltage range (1.7V ~ 1.9V), maximum frequency (400MHz minimum), differential input/output signaling, 1:10 clock ratio, and SSTL-18 signal levels are the primary electrical criteria. Both devices meet these specifications.

Q: How do the package specifications compare?

A: Both devices use 52-pin VFBGA packages with 7x4.5mm dimensions. The CDCU877BZQLT uses MICROSTAR JUNIOR packaging, while the 98ULPA877AHT uses CABGA packaging. These are mechanically compatible form factors suitable for identical PCB layouts.

Q: What impact does the MSL rating difference have on handling and storage?

A: The CDCU877BZQLT (MSL 2, 1 Year) allows extended shelf life storage compared to the 98ULPA877AHT (MSL 3, 168 Hours). The substitute requires more frequent reflow processing or baking cycles if storage exceeds 168 hours at specified humidity levels.

Q: Are there frequency performance differences between these devices?

A: The 98ULPA877AHT operates at 410MHz maximum versus 400MHz for the CDCU877BZQLT. This 10MHz additional margin provides improved performance headroom for high-speed DDR2 clock distribution without functional changes to the 1:10 multiplication ratio.

Q: What compliance considerations apply to the substitute part?

A: The CDCU877BZQLT is ROHS3 compliant; the 98ULPA877AHT is RoHS non-compliant. Applications subject to RoHS directives or customer requirements must retain the original part or identify alternative compliant substitutes. Both devices are REACH unaffected and carry EAR99 export classification.