Equivalent & Substitute Parts for 651MLFT Clock Buffer IC

Part Overview

The 651MLFT is a Clock Fanout Buffer (Distribution) IC manufactured by Renesas Electronics Corporation, designed for 1:4 clock distribution at frequencies up to 200 MHz in 8-SOIC surface mount packaging. This part is classified as Obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations. The 651MLFT operates within a supply voltage range of 1.425V to 2.625V and supports operating temperatures from 0°C to 70°C.

Substiute Parts

651MLFT

Renesas Electronics CorporationIn Stock: 2301651MLFT Datasheet

Current PartRFQ

651SDCGI8

Renesas Electronics CorporationIn Stock: 6901651SDCGI8 Datasheet

MFR RecommendedRFQ

NB3N551DG

onsemiIn Stock: 1176NB3N551DG Datasheet

MFR RecommendedRFQ

NB3N551DR2G

onsemiIn Stock: 2324NB3N551DR2G Datasheet

MFR RecommendedRFQ

PI6CL10804WE

Diodes IncorporatedIn Stock: 1493PI6CL10804WE Datasheet

MFR RecommendedRFQ

PI6CL10804WEX

Diodes IncorporatedIn Stock: 5216PI6CL10804WEX Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 651MLFT is determined by the following critical parameters:

Mechanical Compatibility: All substitute parts must use the 8-SOIC (0.154", 3.90mm Width) package to ensure direct PCB footprint compatibility without layout modifications.

Functional Requirements: Substitute parts must maintain the 1:4 input-to-output ratio and support clock distribution functionality. Maximum frequency capability must meet or exceed 200 MHz to ensure performance parity.

Electrical Compatibility: The supply voltage range of the 651MLFT (1.425V ~ 2.625V) defines the primary substitution constraint. Substitute parts are grouped based on whether their supply voltage ranges overlap with or encompass the original specification.

Signal Compatibility: Input and output signal types (LVCMOS, LVTTL) must be compatible with the original design requirements.

The identified substitute parts fall into two distinct groups based on voltage compatibility and product status:

Group 1 - Direct Voltage Range Overlap: 651SDCGI8 and PI6CL10804WE/PI6CL10804WEX maintain supply voltage ranges that overlap with the 651MLFT specification, ensuring direct substitution without circuit redesign.

Group 2 - Extended Voltage Range: NB3N551DG and NB3N551DR2G operate at higher supply voltages (3V ~ 5.5V) and represent substitutes for applications where voltage level shifting or design modification is acceptable.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No Circuit Modification Required):

The 651SDCGI8 from Renesas Electronics Corporation is the primary recommended substitute. It maintains the same manufacturer lineage, operates within overlapping supply voltage ranges, and supports the full 200 MHz frequency specification. The part is Active status with extended operating temperature range (-40°C to 105°C) and is available in Tape & Reel packaging. ROHS3 compliance and unlimited moisture sensitivity level (MSL 1) match the original specification.

The PI6CL10804WEX from Diodes Incorporated provides an alternative direct replacement option. It matches the 200 MHz frequency requirement and maintains LVCMOS signal compatibility. However, the supply voltage range (1.1V ~ 1.6V) is narrower than the 651MLFT specification and requires circuit validation to confirm compatibility with existing power supply designs.

For Applications Requiring Extended Temperature Range:

The NB3N551DR2G from onsemi offers extended operating temperature capability (-40°C to 85°C) and is available in Tape & Reel packaging. This part operates at higher supply voltages (3V ~ 5.5V) and supports both LVCMOS and LVTTL signal types. The maximum frequency of 180 MHz is below the 651MLFT specification and requires application-level assessment to determine acceptability.

All substitute parts maintain ROHS3 compliance, EAR99 export classification, and identical HTSUS coding, ensuring regulatory and supply chain consistency.

Frequently Asked Questions (FAQ)

Q: Can the 651SDCGI8 be used as a direct drop-in replacement for the 651MLFT?

A: The 651SDCGI8 shares the same 8-SOIC package footprint and maintains overlapping supply voltage ranges within the 651MLFT specification window. Both parts support 1:4 clock distribution at 200 MHz with LVCMOS signal compatibility. Direct PCB substitution is feasible without layout modifications. However, the 651SDCGI8 operates at lower supply voltages (1.71V ~ 1.89V, 2.375V ~ 2.625V, 3.135V ~ 3.465V) compared to the 651MLFT (1.425V ~ 2.625V), requiring verification that the power supply design accommodates these voltage bands.

Q: What is the frequency limitation when using NB3N551 series parts?

A: The NB3N551DG and NB3N551DR2G are specified for maximum frequency of 180 MHz, compared to the 651MLFT specification of 200 MHz. Applications operating clock signals at frequencies between 180 MHz and 200 MHz cannot use these parts without performance degradation. Applications operating below 180 MHz can use these parts with full functional compatibility.

Q: Are there packaging differences between substitute parts?

A: All substitute parts use the 8-SOIC (0.154", 3.90mm Width) package, ensuring identical PCB footprint compatibility. Packaging options differ by supplier: 651SDCGI8 is available in Tape & Reel, NB3N551DG in Tube, NB3N551DR2G in Tape & Reel, PI6CL10804WE in Tube, and PI6CL10804WEX in Tape & Reel. These differences affect supply chain logistics but do not impact electrical or mechanical compatibility.

Q: What supply voltage range should be used when selecting between substitute parts?

A: The 651MLFT operates within 1.425V ~ 2.625V. The 651SDCGI8 supports multiple voltage bands including 1.71V ~ 1.89V and 2.375V ~ 2.625V, both compatible with the original specification. The PI6CL10804 series operates at 1.1V ~ 1.6V, which overlaps partially with the lower end of the 651MLFT range. The NB3N551 series requires 3V ~ 5.5V and is incompatible with the original supply voltage specification without circuit redesign.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All identified substitute parts (651SDCGI8, NB3N551DG, NB3N551DR2G, PI6CL10804WE, PI6CL10804WEX) are ROHS3 compliant and maintain regulatory consistency with the 651MLFT specification.

Q: What is the operating temperature range difference between the 651MLFT and substitute parts?

A: The 651MLFT operates from 0°C to 70°C. All substitute parts extend the lower temperature limit to -40°C and upper limits to either 85°C or 105°C (651SDCGI8). Applications requiring operation within the original 0°C to 70°C window can use any substitute part. Applications requiring operation below 0°C or above 70°C must select substitute parts with extended temperature specifications.