Renesas 621MLF Clock Buffer IC - Equivalent & Substitute Parts

Part Overview

The Renesas 621MLF is a Clock Fanout Buffer (Distribution) IC with 1:4 output ratio and 200 MHz maximum frequency in 8-SOIC packaging. This part is classified as obsolete, making equivalent substitute components necessary for new designs and ongoing production requirements. The 621MLF provides LVCMOS output from clock input signals and operates across a supply voltage range of 1.14V to 1.89V with a temperature range of 0°C to 70°C.

Substiute Parts

621MLF

Renesas Electronics CorporationIn Stock: 1012621MLF Datasheet

Current PartRFQ

621SDCGI

Renesas Electronics CorporationIn Stock: 1204621SDCGI 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 eligibility for the 621MLF is determined by the following critical parameters:

Primary Compatibility Criteria:

• Package / Case: 8-SOIC (0.154", 3.90mm Width) - physical and electrical footprint compatibility
• Ratio - Input:Output: 1:4 - functional output distribution requirement
• Mounting Type: Surface Mount - assembly process compatibility
• Number of Circuits: 1 - single buffer circuit configuration

Secondary Compatibility Criteria:

• Frequency - Max: 200 MHz or higher - clock distribution capability
• Input/Output Signal Types: Clock input with LVCMOS or LVTTL output compatibility
• Differential Input/Output: No/No - single-ended signal architecture

Compliance & Certification:

• RoHS3 Compliant status required for regulatory alignment
• Moisture Sensitivity Level: 1 (Unlimited) - handling and storage compatibility

The substitute parts listed below meet these core electrical and mechanical parameters while offering active product status and extended operating temperature ranges compared to the obsolete 621MLF.

Parameter Comparison

Engineering Selection Recommendations

621SDCGI (Renesas Electronics Corporation)

The 621SDCGI is the manufacturer-recommended direct substitute from Renesas. It maintains the same 1:4 fanout buffer architecture and 200 MHz frequency specification within an 8-SOIC package. The extended operating temperature range of -40°C to 105°C provides broader environmental coverage compared to the 621MLF. Supply voltage range of 1.71V to 3.465V accommodates the original 1.14V to 1.89V specification. Active product status ensures long-term availability and supply chain continuity. ROHS3 compliance and MSL 1 rating match the original part specifications.

NB3N551DG and NB3N551DR2G (onsemi)

Both onsemi variants provide 1:4 fanout buffer functionality in 8-SOIC packaging with active product status. The 180 MHz maximum frequency specification is lower than the 621MLF 200 MHz rating. Supply voltage range of 3V to 5.5V represents a significant departure from the original 1.14V to 1.89V specification and requires circuit-level evaluation. The NB3N551DR2G is supplied in Tape & Reel packaging with higher inventory availability (2269 pcs) compared to the tube-packaged NB3N551DG (1105 pcs). Both support LVCMOS and LVTTL input/output compatibility with operating temperature range of -40°C to 85°C.

PI6CL10804WE and PI6CL10804WEX (Diodes Incorporated)

Both Diodes Incorporated variants maintain the 200 MHz frequency specification and 1:4 fanout buffer configuration in 8-SOIC packaging. Supply voltage range of 1.1V to 1.6V closely aligns with the original 1.14V to 1.89V specification, minimizing circuit redesign requirements. Operating temperature range of -40°C to 85°C extends the original 0°C to 70°C specification. The PI6CL10804WEX is supplied in Tape & Reel packaging with significantly higher inventory (5200 pcs) compared to the tube-packaged PI6CL10804WE (1391 pcs). Both parts maintain ROHS3 compliance and MSL 1 rating.

Frequently Asked Questions (FAQ)

Q: Can the 621SDCGI directly replace the 621MLF without circuit modifications?

A: The 621SDCGI shares the same 1:4 fanout buffer architecture, 200 MHz frequency specification, and 8-SOIC package footprint. The extended supply voltage range of 1.71V to 3.465V encompasses the original 1.14V to 1.89V specification. Direct PCB-level substitution is supported by matching package geometry and pin configuration. Circuit-level evaluation is required to confirm compatibility with existing power supply and signal conditioning designs.

Q: What is the primary difference between the onsemi NB3N551DG and NB3N551DR2G?

A: Both parts are electrically identical with 1:4 fanout buffer functionality, 180 MHz frequency specification, and 8-SOIC packaging. The primary difference is packaging format: NB3N551DG is supplied in Tube packaging, while NB3N551DR2G is supplied in Tape & Reel (TR) format. The NB3N551DR2G offers higher inventory availability (2269 pcs) and is suitable for automated assembly processes requiring reel-based component feeding.

Q: How do the Diodes Incorporated PI6CL10804WE and PI6CL10804WEX differ?

A: Both parts are electrically identical with 200 MHz frequency specification and 1:4 fanout buffer configuration in 8-SOIC packaging. The PI6CL10804WE is supplied in Tube packaging (1391 pcs inventory), while the PI6CL10804WEX is supplied in Tape & Reel format (5200 pcs inventory). Selection depends on assembly process requirements and component procurement volume.

Q: Why is the NB3N551 series rated at 180 MHz instead of 200 MHz?

A: The onsemi NB3N551 series specifies a maximum frequency of 180 MHz, which is lower than the 621MLF 200 MHz specification. This represents a functional limitation for applications requiring the full 200 MHz clock distribution capability. The NB3N551 series is suitable for applications operating at or below 180 MHz clock frequencies.

Q: Are all substitute parts ROHS3 compliant?

A: All substitute parts listed (621SDCGI, NB3N551DG, NB3N551DR2G, PI6CL10804WE, PI6CL10804WEX) maintain ROHS3 compliance status matching the original 621MLF specification. Moisture Sensitivity Level 1 (Unlimited) is consistent across all parts, indicating equivalent handling and storage requirements.

Q: What supply voltage considerations apply when selecting a substitute?

A: The 621MLF operates at 1.14V to 1.89V. The 621SDCGI (1.71V to 3.465V) and PI6CL10804 series (1.1V to 1.6V) maintain close voltage alignment with minimal circuit redesign. The onsemi NB3N551 series (3V to 5.5V) represents a significant voltage departure and requires comprehensive circuit-level evaluation to confirm compatibility with existing power distribution and signal integrity designs.

Q: Can the 621MLF be used in new designs, or must a substitute be selected?

A: The 621MLF is classified as obsolete, indicating discontinued manufacturing and limited long-term availability. New designs should select from active substitute parts to ensure supply chain continuity and long-term component availability. The 621SDCGI or PI6CL10804 series are recommended for new designs requiring 200 MHz frequency capability.