DSS41A24B Reed Relay SPST 500mA 24VDC Equivalent & Substitute Parts

Part Overview

The DSS41A24B is a through-hole mounted reed relay manufactured by Coto Technology, designed for SPST-NO (Single Pole Single Throw, Normally Open) switching applications at 24VDC coil voltage with 500mA contact rating. This component is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing system support, design updates, and procurement continuity. The DSS41A24B operates across industrial temperature ranges and maintains RoHS compliance, requiring substitutes that preserve these critical characteristics while accommodating modern component availability.

Substiute Parts

DSS41A24B

Coto TechnologyIn Stock: 883DSS41A24B Datasheet

Current PartRFQ

HE3621A2410

Littelfuse Inc.In Stock: 1982HE3621A2410 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the DSS41A24B is determined by strict alignment across the following critical parameters:

Primary Matching Criteria (Non-Negotiable):

• Coil Voltage: 24VDC
• Contact Form: SPST-NO (1 Form A)
• Contact Rating (Current): 500 mA minimum
• Switching Voltage: 200VDC minimum
• Mounting Type: Through Hole
• Termination Style: PC Pin
• Operating Temperature Range: -40°C ~ 85°C minimum
• Coil Type: Non Latching

Secondary Compliance Criteria:

• RoHS Status: RoHS Compliant or higher revision
• REACH Status: REACH Unaffected
• Moisture Sensitivity Level: 1 (Unlimited)

The HE3621A2410 manufactured by Littelfuse Inc. satisfies all primary and secondary matching criteria, establishing it as a direct functional equivalent. Both components operate at identical coil voltage, contact form, current rating, and temperature range. The substitute maintains equivalent switching voltage capability (200VDC) and shares identical termination and mounting specifications. Compliance certifications are preserved across both RoHS and REACH standards.

Parameter Comparison

Engineering Selection Recommendations

HE3621A2410 as Primary Substitute:

The HE3621A2410 is the qualified equivalent for DSS41A24B replacement applications. Selection is based on the following engineering factors:

Compliance & Regulatory Status: The HE3621A2410 maintains RoHS3 compliance, representing a higher revision level than the original RoHS Compliant designation of the DSS41A24B. Both components are REACH Unaffected and carry identical Moisture Sensitivity Level 1 ratings, ensuring regulatory continuity across procurement and assembly processes.

Product Lifecycle Status: The DSS41A24B is classified as obsolete, while the HE3621A2410 maintains active manufacturing status. This distinction ensures long-term component availability, supply chain stability, and access to current manufacturing documentation and technical support from Littelfuse Inc.

Functional Equivalence: Both relays operate at 24VDC coil voltage with SPST-NO contact form and 500mA current rating. Identical through-hole mounting and PC pin termination enable direct PCB footprint compatibility without layout modifications. Operating temperature range (-40°C ~ 85°C) is preserved across both components.

Electrical Performance Characteristics: The HE3621A2410 exhibits slightly lower coil current (11.1 mA versus 12 mA) and reduced must-operate voltage (16 VDC versus 17.5 VDC), resulting in improved sensitivity and reduced power consumption. Switching voltage capability (200VDC) meets or exceeds the original specification. Timing parameters (1 ms operate and release times versus 0.5 ms) represent acceptable operational differences for non-time-critical switching applications. Coil resistance variance (2.15 kOhms versus 2 kOhms) falls within standard engineering tolerance.

Packaging & Inventory: The HE3621A2410 is supplied in tube packaging with 1892 units in current stock, providing immediate procurement availability compared to the obsolete DSS41A24B status.

Frequently Asked Questions (FAQ)

Q: Can the HE3621A2410 be used as a direct replacement for DSS41A24B without PCB modifications?

A: Yes. Both components share identical through-hole mounting type and PC pin termination style. PCB footprints are compatible, and no layout changes are required for substitution.

Q: What is the significance of the coil current difference (12 mA vs. 11.1 mA)?

A: The HE3621A2410 draws 0.9 mA less coil current, reducing power consumption and heat generation in the relay coil. This represents an improvement over the original specification and does not affect circuit compatibility. Existing drive circuits designed for 12 mA operation will function correctly with the lower-current substitute.

Q: Why does the HE3621A2410 have longer operate and release times (1 ms vs. 0.5 ms)?

A: The timing difference reflects different internal mechanical designs between Coto Technology and Littelfuse reed relay architectures. For applications requiring sub-millisecond switching precision, timing performance must be verified against specific circuit requirements. For general industrial switching applications, 1 ms timing is within standard relay performance parameters.

Q: Is the HE3621A2410 RoHS compliant?

A: Yes. The HE3621A2410 carries ROHS3 compliance certification, which represents a higher revision level than the RoHS Compliant status of the DSS41A24B. This ensures continued regulatory compliance and future-proofed material composition standards.

Q: What does the "Diode" feature listed for HE3621A2410 indicate?

A: The integrated diode provides transient suppression across the relay coil, protecting drive circuits from voltage spikes during relay de-energization. This feature enhances circuit reliability and is compatible with standard relay drive topologies.

Q: Are there any temperature range limitations when substituting?

A: No. Both components operate across the identical temperature range of -40°C ~ 85°C, ensuring equivalent thermal performance across all environmental conditions.

Q: What is the difference in must-operate and must-release voltages?

A: The HE3621A2410 requires 16 VDC to operate (versus 17.5 VDC for DSS41A24B) and 2 VDC to release (versus 2.5 VDC). The substitute exhibits greater sensitivity, meaning it will activate at lower coil voltages. For applications with stable 24VDC supplies, this difference is operationally transparent and represents improved performance.

Q: Can the HE3621A2410 handle the same switching voltage as the DSS41A24B?

A: Yes. The HE3621A2410 is rated for 200VDC maximum switching voltage, matching the DSS41A24B specification. Both components are suitable for identical load voltage applications up to 200VDC.

Q: Is the tube packaging of HE3621A2410 compatible with existing assembly processes?

A: Tube packaging is standard for through-hole relay components and is compatible with conventional pick-and-place assembly equipment and manual insertion processes. Verify packaging format compatibility with your specific assembly workflow.

Q: What is the coil resistance tolerance, and does the 2.15 kOhm versus 2 kOhm difference matter?

A: The 0.15 kOhm difference (7.5% variance) falls within standard relay manufacturing tolerances and does not affect circuit operation. Both resistances are functionally equivalent for drive circuit design purposes.