L77DFB25S1BUN D-Sub Receptacle Connector - Equivalent & Substitute Parts

Part Overview

The L77DFB25S1BUN is a 25-position D-Sub receptacle connector manufactured by Amphenol ICC (Commercial Products). This right-angle solder connector features panel mount and through-hole mounting capability with gold-plated machined contacts and a tin-plated steel shell. The part is currently in active production status. Substitute parts are necessary when the original manufacturer discontinues production, when supply constraints occur, or when alternative compliance certifications are required for specific applications.

Substiute Parts

L77DFB25S1BUN

Amphenol ICC (Commercial Products)In Stock: 756L77DFB25S1BUN Datasheet

Current PartRFQ

173-E25-213R001

NorComp Inc.In Stock: 1275173-E25-213R001 Datasheet

SimilarRFQ

174-E25-211R001

NorComp Inc.In Stock: 1217174-E25-211R001 Datasheet

SimilarRFQ

174-E25-211R141

NorComp Inc.In Stock: 1041174-E25-211R141 Datasheet

SimilarRFQ

174-E25-211R241

NorComp Inc.In Stock: 1127174-E25-211R241 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the L77DFB25S1BUN is determined by the following critical parameters:

Mandatory Compatibility Parameters:

• Connector Style: D-Sub
• Connector Type: Receptacle, Female Sockets
• Number of Positions: 25
• Number of Rows: 2
• Shell Size, Connector Layout: 3 (DB, B)
• Contact Type: Signal
• Termination: Solder
• Mounting Type: Right Angle (with Panel Mount capability preferred)
• Contact Form: Machined

Functional Performance Parameters:

• Current Rating: 7.5A (minimum acceptable)
• Voltage Rating: 300V (minimum acceptable)
• Operating Temperature Range: -55°C to 155°C (minimum acceptable)
• Contact Finish: Gold
• Backset Spacing: 0.406" (10.30mm)

Compliance Parameters:

• RoHS Status: Compliant variants preferred
• Material Flammability Rating: UL94 V-0

The four substitute parts identified (173-E25-213R001, 174-E25-211R001, 174-E25-211R141, 174-E25-211R241) all share the mandatory D-Sub receptacle configuration with 25 positions, right-angle solder termination, and machine-tooled contacts. However, variations exist in current rating, backset spacing, operating temperature range, shell finish material, and product status that must be evaluated during part selection.

Parameter Comparison

Engineering Selection Recommendations

173-E25-213R001 (NorComp M Series)

This part represents the most viable active-status substitute. It shares the core D-Sub 25-position receptacle architecture with identical shell size and solder termination. However, application feasibility depends on the following considerations:

• Current Rating: 5A versus 7.5A in the original part. Applications requiring the full 7.5A capacity will not be supported by this substitute.
• Backset Spacing: 0.283" (7.20mm) differs significantly from the original 0.406" (10.30mm). PCB layout compatibility must be verified.
• Operating Temperature Range: -55°C to 125°C versus -55°C to 155°C. The upper temperature limit is reduced by 30°C.
• Mounting Type: Lacks panel mount designation; through-hole and right-angle capability are confirmed.
• RoHS Status: ROHS3 Compliant, exceeding the original RoHS Compliant designation.

174-E25-211R001, 174-E25-211R141, 174-E25-211R241 (NorComp M Series)

These three parts share identical electrical and physical characteristics but are currently in Obsolete product status. Selection of obsolete parts introduces supply chain risk and should only be considered when:

• Supply of active alternatives is exhausted.
• Legacy system maintenance requires component-level compatibility.
• Current and voltage requirements do not exceed 5A and the voltage rating is not specified but inferred from standard D-Sub operation.

Common limitations across all three obsolete parts:

• Current Rating: 5A (not suitable for 7.5A applications).
• Operating Temperature Range: -50°C to 100°C (significantly reduced upper limit).
• RoHS Non-compliant status. Applications subject to RoHS requirements cannot use these parts.
• Backset Spacing: 0.370" (9.40mm), creating mechanical incompatibility with the original 0.406" (10.30mm) spacing.

Differentiating characteristics among the three:

• 174-E25-211R001: Panel mount, through-hole, right-angle with unthreaded housing flange.
• 174-E25-211R141: Adds female screwlock (4-40) mating-side flange; mounting brackets included.
• 174-E25-211R241: Standard 4-40 screws on mating-side flange; mounting brackets included.

Frequently Asked Questions (FAQ)

Q: Can I substitute the 173-E25-213R001 for the L77DFB25S1BUN in my application?

A: Substitution depends on three factors. First, verify that your application current requirements do not exceed 5A, as the substitute is rated for 5A versus the original 7.5A. Second, confirm PCB layout compatibility with the reduced backset spacing of 0.283" (7.20mm) versus the original 0.406" (10.30mm)—this represents a significant dimensional difference. Third, verify that your operating temperature maximum does not exceed 125°C, as the substitute's upper limit is 30°C lower than the original part.

Q: Why do the NorComp substitutes have different backset spacings?

A: Backset spacing is the distance from the back of the connector shell to the seating plane of the contacts. Different manufacturers use different designs, resulting in variations ranging from 0.283" to 0.406" across the available 25-position D-Sub receptacles. This parameter directly affects PCB mounting hole placement and cannot be changed without redesigning the PCB footprint.

Q: Are the obsolete NorComp parts (174-E25-211R001, 174-E25-211R141, 174-E25-211R241) acceptable for new designs?

A: No. Obsolete parts should not be selected for new designs due to supply discontinuation risk. These parts are presented for reference only when servicing legacy equipment or when no other alternatives are available. Additionally, these parts are RoHS non-compliant and have reduced current ratings and operating temperature ranges compared to the original L77DFB25S1BUN.

Q: What is the difference between the three obsolete NorComp 174-E25 variants?

A: All three share identical electrical specifications (5A current, -50°C to 100°C operating range, yellow chromate-plated steel shell). They differ only in the flange feature design. The 174-E25-211R001 has an unthreaded housing flange. The 174-E25-211R141 adds female screwlock (4-40) fasteners with mounting brackets. The 174-E25-211R241 uses standard 4-40 screws with mounting brackets. Select based on your mechanical attachment requirements, but prioritize supply chain viability when making this choice.

Q: Why does the original part have a 7.5A current rating while most substitutes are rated for 5A?

A: Current rating depends on multiple factors including contact material, contact plating thickness, conductor cross-sectional area, and thermal dissipation design. The L77DFB25S1BUN uses copper alloy contacts with thicker gold plating (20.0µin) compared to the NorComp substitutes, which use either copper or brass with flash gold plating. These material differences result in higher current-carrying capacity in the original part.

Q: Is the difference in contact finish (20.0µin gold versus flash gold plating) significant?

A: Yes. The L77DFB25S1BUN contact finish thickness of 20.0µin (0.51µm) provides greater corrosion resistance and durability compared to flash gold plating used on NorComp substitutes. Flash gold plating is thinner and provides lower contact resistance initially but offers reduced protection against environmental degradation in high-humidity or corrosive environments over extended service life.

Q: Which substitute part should I choose if RoHS compliance is mandatory?

A: Only the 173-E25-213R001 is RoHS-compliant (ROHS3 Compliant status). The three NorComp 174-E25 variants are explicitly RoHS non-compliant and cannot be used in applications subject to RoHS regulatory requirements. If RoHS compliance is required and the 173-E25-213R001 electrical and dimensional parameters do not match your application, no substitute from this list is acceptable.