PRMA1A24 Reed Relay Equivalent & Substitute Parts

Part Overview

The PRMA1A24 is a through-hole mounted reed relay manufactured by Coto Technology, designed for single-pole single-throw (SPST) switching applications at 24VDC coil voltage with 500mA contact rating. This component is classified as obsolete, necessitating identification of active equivalent parts for new designs and ongoing production requirements. The relay operates across an industrial temperature range of -40°C to 80°C and features non-latching coil operation with PC pin termination.

Substiute Parts

PRMA1A24

Coto TechnologyIn Stock: 1717PRMA1A24 Datasheet

Current PartRFQ

HE721A2400

Littelfuse Inc.In Stock: 5098HE721A2400 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the PRMA1A24 is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Coil voltage: 24VDC
• Contact form: SPST-NO (1 Form A)
• Contact rating: 500 mA minimum
• Termination style: PC Pin
• Mounting type: Through Hole
• Coil type: Non Latching

Allowable Variation Parameters:

• Must operate voltage: Substitute may require lower activation voltage (16VDC vs. 18VDC)
• Operate/Release time: Substitute may have longer switching times (1ms vs. 0.5ms)
• Operating temperature upper limit: Substitute may extend to 85°C vs. 80°C
• Switching voltage: Substitute may have reduced maximum (200VDC only vs. 200VAC/200VDC)
• Coil current: Substitute may vary within ±1% tolerance (11.1mA vs. 11.2mA)

The HE721A2400 from Littelfuse Inc. qualifies as a functional equivalent based on these parameters.

Parameter Comparison

Engineering Selection Recommendations

The HE721A2400 from Littelfuse Inc. serves as the primary equivalent for the obsolete PRMA1A24. Selection of this substitute is supported by the following factors:

Compliance and Regulatory Status: The HE721A2400 maintains ROHS3 compliance, exceeding the RoHS compliance of the original part. Both components are REACH unaffected and carry identical ECCN and HTSUS classifications, ensuring regulatory continuity.

Product Availability: The HE721A2400 is classified as active product status with 5006 units in stock, compared to the obsolete PRMA1A24. This ensures long-term supply chain viability for production and design requirements.

Functional Equivalence: Core switching parameters are identical: 24VDC coil voltage, SPST-NO contact form, 500mA contact rating, 2.15kOhm coil resistance, and PC pin termination. Both components are non-latching relays with through-hole mounting.

Parameter Deviations: The HE721A2400 exhibits three measurable deviations from the PRMA1A24. The must-operate voltage is reduced from 18VDC to 16VDC, providing improved sensitivity. Switching times (operate and release) are doubled from 0.5ms to 1ms. The maximum switching voltage is limited to 200VDC only, eliminating 200VAC capability. The operating temperature upper limit extends from 80°C to 85°C.

Application Suitability: The HE721A2400 is suitable for applications where the reduced switching time and lower activation voltage do not conflict with circuit timing or power supply specifications. Applications requiring 200VAC switching capability require alternative evaluation.

Frequently Asked Questions (FAQ)

Q: Can the HE721A2400 directly replace the PRMA1A24 in existing PCB designs?

A: The HE721A2400 features identical PC pin termination and through-hole mounting, enabling direct physical substitution on PCBs designed for the PRMA1A24. No board layout modifications are required.

Q: What is the impact of the doubled switching time (1ms vs. 0.5ms)?

A: The HE721A2400 operates and releases in 1ms compared to the PRMA1A24's 0.5ms. This affects circuit timing in applications requiring rapid relay response. Circuits with timing margins exceeding 1ms are unaffected.

Q: Does the lower must-operate voltage (16VDC vs. 18VDC) create compatibility issues?

A: The lower activation threshold of the HE721A2400 represents improved sensitivity. Circuits designed for 18VDC operation will activate the substitute at 16VDC, which is acceptable in most applications. Circuits with voltage regulation below 16VDC may experience unintended activation.

Q: Why does the HE721A2400 lack 200VAC switching capability?

A: The HE721A2400 is rated for 200VDC maximum switching voltage only, eliminating AC switching capability present in the PRMA1A24. Applications requiring AC switching must evaluate alternative substitutes or retain the original part if available.

Q: Are there packaging differences between these relays?

A: The PRMA1A24 is supplied without specified packaging, while the HE721A2400 is packaged in tubes. Both components use identical PC pin termination and through-hole mounting, with no functional impact from packaging format.

Q: What is the significance of ROHS3 compliance on the HE721A2400?

A: ROHS3 compliance represents current regulatory standards for restricted hazardous substances. The HE721A2400 meets or exceeds the RoHS compliance of the original PRMA1A24, ensuring regulatory alignment for new designs and production.

Q: Can the HE721A2400 operate across the full temperature range of the PRMA1A24?

A: The HE721A2400 operates from -40°C to 85°C, exceeding the PRMA1A24's -40°C to 80°C range. Both components function across the original part's temperature specification.