Equivalent & Substitute Parts for Renesas 621MLFT Clock Buffer IC

Part Overview

The Renesas 621MLFT 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 substitute components necessary for new designs and ongoing production requirements. The 621MLFT operates at low supply voltages (1.14V to 1.89V) with LVCMOS output logic levels, serving applications requiring clock distribution in compact form factors.

Substiute Parts

621MLFT

Renesas Electronics CorporationIn Stock: 1101621MLFT Datasheet

Current PartRFQ

621SDCGI8

Renesas Electronics CorporationIn Stock: 3281621SDCGI8 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 for the 621MLFT is determined by the following critical parameters:

Primary Compatibility Criteria:

• Package type: 8-SOIC (0.154", 3.90mm Width) form factor
• Input/Output ratio: 1:4 configuration
• Maximum frequency: 200 MHz or higher
• Output logic: LVCMOS
• Mounting type: Surface Mount

Substitution Categories:

The substitute parts are grouped into two functional categories based on supply voltage compatibility:

Category A - Low Voltage Direct Substitutes (1.1V ~ 1.89V Supply):

• 621SDCGI8 (Renesas, active status, extended temperature range)
• PI6CL10804WE (Diodes Incorporated, active status)
• PI6CL10804WEX (Diodes Incorporated, active status)

These parts maintain the original low-voltage supply specification of the 621MLFT while offering active product status and improved temperature operating ranges.

Category B - Standard Voltage Substitutes (3V ~ 5.5V Supply):

• NB3N551DG (onsemi, active status)
• NB3N551DR2G (onsemi, active status)

These parts operate at standard logic supply voltages and are suitable for applications where supply voltage flexibility is acceptable. Maximum frequency is 180 MHz, which is within the 621MLFT's 200 MHz specification.

Parameter Comparison

Engineering Selection Recommendations

For Low-Voltage Supply Applications (1.1V ~ 1.89V):

The 621SDCGI8, PI6CL10804WE, and PI6CL10804WEX maintain the original supply voltage specification of the 621MLFT. All three are active products with ROHS3 compliance. The 621SDCGI8 offers the widest operating temperature range (-40°C to 105°C) and supports multiple supply voltage bands, providing design flexibility. The Diodes Incorporated parts (PI6CL10804WE and PI6CL10804WEX) maintain strict low-voltage operation and are available in higher inventory quantities.

For Standard Logic Supply Applications (3V ~ 5.5V):

The NB3N551DG and NB3N551DR2G from onsemi are suitable substitutes when supply voltage can be adjusted to standard logic levels. Both parts are active products with ROHS3 compliance and extended temperature ranges (-40°C to 85°C). The maximum frequency specification of 180 MHz remains within acceptable limits for most clock distribution applications requiring the 621MLFT's 200 MHz capability.

Selection Priority:

1. Verify supply voltage requirements in the target application
2. Confirm operating temperature range compatibility
3. Validate frequency margin requirements (180 MHz vs. 200 MHz)
4. Confirm packaging and mounting compatibility (all substitutes use 8-SOIC)
5. Prioritize active product status for long-term availability

Frequently Asked Questions (FAQ)

Q: Can the NB3N551DG or NB3N551DR2G be used as direct replacements for the 621MLFT?

A: These parts are functionally compatible substitutes with identical 1:4 fanout ratio and 8-SOIC packaging. However, they require supply voltages in the 3V to 5.5V range, whereas the 621MLFT operates at 1.14V to 1.89V. Application circuit redesign may be necessary if the original design uses low-voltage supplies.

Q: What is the difference between PI6CL10804WE and PI6CL10804WEX?

A: Both parts are identical in electrical specifications and performance. The difference is packaging: PI6CL10804WE is supplied in Tube packaging, while PI6CL10804WEX is supplied in Tape & Reel (TR) format. Selection depends on assembly process requirements and inventory management preferences.

Q: Is the 621SDCGI8 a complete replacement for the 621MLFT?

A: The 621SDCGI8 is a functional equivalent with identical frequency and fanout ratio specifications. It supports the original 1.71V to 1.89V supply range of the 621MLFT, plus additional voltage bands. The 621SDCGI8 offers extended operating temperature range (-40°C to 105°C versus 0°C to 70°C), making it suitable for broader application environments.

Q: Why do some substitutes have lower maximum frequency (180 MHz vs. 200 MHz)?

A: The NB3N551DG and NB3N551DR2G are specified at 180 MHz maximum frequency. This specification remains within the operational envelope of most clock distribution applications. Frequency margin verification against specific application requirements is necessary before selection.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed (621SDCGI8, NB3N551DG, NB3N551DR2G, PI6CL10804WE, PI6CL10804WEX) are ROHS3 compliant, matching the compliance status of the original 621MLFT.

Q: What packaging options are available for these substitutes?

A: All substitute parts use the same 8-SOIC (0.154", 3.90mm Width) package as the 621MLFT. Packaging format varies by part number: some are supplied in Tube format, others in Tape & Reel (TR) format. Verify packaging compatibility with assembly equipment and procurement requirements.