MDCG-4-37-43 Equivalent & Substitute Parts

Part Overview

The MDCG-4-37-43 is a glass body reed switch manufactured by Littelfuse Inc., configured as a single-pole single-throw normally open (SPST-NO) device. This component is designed for low-power switching applications requiring reliable contact closure in the presence of a magnetic field. The part is currently in active production status with 1556 units available in inventory. Substitute parts are identified when equivalent electrical performance and mechanical compatibility can be maintained within the specified parameter ranges for this product category.

Substiute Parts

MDCG-4-37-43

Littelfuse Inc.In Stock: 1644MDCG-4-37-43 Datasheet

Current PartRFQ

KSK-1A66/3-2030

Standex-Meder ElectronicsIn Stock: 1307KSK-1A66/3-2030 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MDCG-4-37-43 is determined by the following critical parameters:

Circuit Configuration: Must be SPST-NO to maintain functional equivalence in single-pole switching applications.

Mounting and Termination: Must support through-hole mounting with axial termination to ensure mechanical compatibility with existing PCB layouts.

Electrical Performance: Substitute parts must meet or exceed the switching current and voltage specifications. The MDCG-4-37-43 operates at 350 mA (AC) and 500 mA (DC) at 140 V (AC) and 200 V (DC) respectively. Substitute parts with higher current or voltage ratings remain compatible for this application.

Operating Temperature Range: Must encompass or exceed the -40°C to 125°C range to ensure reliable operation across the specified environmental conditions.

Compliance and Certifications: Parts must maintain ROHS3 compliance and REACH unaffected status to meet regulatory requirements.

Operate Range (Actuation Threshold): While the MDCG-4-37-43 specifies 37 ~ 43 AT, substitute parts with different operate ranges remain functionally equivalent if the magnetic field strength in the application can accommodate the alternative threshold.

Parameter Comparison

Engineering Selection Recommendations

The KSK-1A66/3-2030 from Standex-Meder Electronics is identified as a manufacturer-recommended substitute for the MDCG-4-37-43. Both components maintain active product status and full compliance with ROHS3 and REACH requirements.

The KSK-1A66/3-2030 provides enhanced electrical performance with 500 mA AC switching current (compared to 350 mA on the MDCG-4-37-43) and 200 V AC switching voltage (compared to 140 V on the MDCG-4-37-43). The operating temperature range extends to 130°C, providing a 5°C margin above the MDCG-4-37-43 specification.

Both parts are rated for 10 W power dissipation and maintain identical through-hole axial termination, ensuring direct mechanical compatibility in existing circuit designs. The substitute part is suitable for applications where the MDCG-4-37-43 is unavailable or where the enhanced electrical ratings provide design margin.

Frequently Asked Questions (FAQ)

Q: Can the KSK-1A66/3-2030 be used as a direct replacement for the MDCG-4-37-43 in existing designs?

A: Yes. Both parts share identical circuit configuration (SPST-NO), mounting type (through hole), and termination style (axial). The KSK-1A66/3-2030 meets or exceeds all electrical specifications of the MDCG-4-37-43, including current, voltage, and power ratings. Compliance certifications are equivalent.

Q: What is the difference in operate range between these parts?

A: The MDCG-4-37-43 operates at 37 ~ 43 AT, while the KSK-1A66/3-2030 operates at 20 ~ 30 AT. The operate range defines the magnetic field strength required to close the switch contacts. Selection between these parts depends on the magnetic field strength available in the application. Both are functionally equivalent reed switches with different actuation thresholds.

Q: Are there any physical dimension differences that affect PCB layout?

A: The MDCG-4-37-43 has an overall length of 1.590" (40.39 mm), while the KSK-1A66/3-2030 measures 1.744" (44.30 mm). Body diameters are similar: 0.090" (2.28 mm) versus 0.087" (2.20 mm). These minor differences do not affect through-hole mounting compatibility but should be verified against specific PCB layout constraints.

Q: Do both parts meet the same regulatory requirements?

A: Yes. Both the MDCG-4-37-43 and KSK-1A66/3-2030 are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory standards for electronic components.

Q: What is the packaging difference between these parts?

A: The MDCG-4-37-43 is supplied in box packaging, while the KSK-1A66/3-2030 is supplied in bulk packaging. This affects order quantities and handling but does not impact component performance or compatibility.