MDCG-4-17-28 Equivalent & Substitute Parts

Part Overview

The MDCG-4-17-28 is a glass body reed switch manufactured by Littelfuse Inc., configured as a single-pole single-throw normally open (SPST-NO) device. This through-hole mounted component is designed for low-power switching applications with a rated power of 10W and switching current capacity of 350mA (AC) or 500mA (DC) at 140V AC / 200V DC. The part is currently active in production with full RoHS3 compliance and unlimited moisture sensitivity rating (MSL 1). Substitute parts are identified when equivalent electrical performance and mechanical compatibility can be maintained within the specified operating parameters.

Substiute Parts

MDCG-4-17-28

Littelfuse Inc.In Stock: 1540MDCG-4-17-28 Datasheet

Current PartRFQ

KSK-1A35-1015

Standex-Meder ElectronicsIn Stock: 3690KSK-1A35-1015 Datasheet

MFR RecommendedRFQ

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-4-17-28 is determined by the following critical parameters:

Circuit Configuration: All substitutes must maintain SPST-NO functionality to preserve switching behavior in the application.

Switching Voltage & Current: Substitute parts must support the application's voltage and current requirements. The MDCG-4-17-28 operates at 140V AC / 200V DC with 350mA (AC) or 500mA (DC) switching capacity. Substitutes with equal or higher voltage and current ratings are acceptable.

Mounting Type & Termination: The through-hole axial termination of the MDCG-4-17-28 defines the physical interface. Substitutes with compatible mounting and termination styles ensure direct board-level compatibility.

Operating Temperature Range: The -40°C ~ 125°C range must be maintained or exceeded by substitute parts to ensure reliable operation across the intended thermal environment.

Compliance & Certifications: RoHS3 compliance and MSL 1 rating are mandatory for substitution to maintain regulatory and environmental standards.

Two substitute parts are identified: KSK-1A35-1015 and KSK-1A66/3-2030, both manufactured by Standex-Meder Electronics. These parts meet the electrical and mechanical criteria for substitution within their respective parameter ranges.

Parameter Comparison

Engineering Selection Recommendations

KSK-1A66/3-2030 (Primary Substitute): This part maintains through-hole mounting with axial termination, directly compatible with the MDCG-4-17-28 board interface. Electrical specifications exceed the original part: 500mA (AC/DC) switching current at 200V AC/DC, 10W rated power, and -40°C ~ 130°C operating range. The operate range of 20 ~ 30AT closely aligns with the original 17 ~ 28AT specification. All compliance certifications (RoHS3, MSL 1, REACH Unaffected, EAR99) match the original part. This substitute is suitable for direct replacement in through-hole applications.

KSK-1A35-1015 (Alternative Substitute): This part provides higher switching current capacity (1A AC/DC) and rated power (20W) compared to the MDCG-4-17-28, with 200V AC/DC voltage support and -40°C ~ 130°C operating range. However, the mounting type is surface mount with flat termination, requiring PCB layout modification and rework procedures. The operate range of 10 ~ 15AT differs from the original specification. This substitute is applicable only when PCB redesign for surface mount is feasible and the lower operate range is acceptable for the application.

Both substitutes maintain active product status and full regulatory compliance. Selection depends on mounting compatibility requirements and operate range tolerance.

Frequently Asked Questions (FAQ)

Q: Can KSK-1A35-1015 be used as a direct replacement for MDCG-4-17-28?

A: No. While KSK-1A35-1015 meets the electrical requirements (1A switching current, 200V, 20W power), it uses surface mount termination instead of through-hole axial termination. Direct board-level substitution is not possible without PCB redesign and component rework.

Q: What is the primary difference between the two substitute parts?

A: KSK-1A66/3-2030 maintains through-hole mounting compatibility with the original MDCG-4-17-28, while KSK-1A35-1015 requires surface mount implementation. KSK-1A35-1015 offers higher current capacity (1A vs. 500mA) and power rating (20W vs. 10W), but operates at a lower magnetic range (10 ~ 15AT vs. 20 ~ 30AT).

Q: Are the substitute parts RoHS3 compliant?

A: Yes. Both KSK-1A66/3-2030 and KSK-1A35-1015 are RoHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, matching the original MDCG-4-17-28 compliance profile.

Q: What is the operate range, and why does it matter for substitution?

A: The operate range (measured in Ampere-Turns, AT) defines the magnetic field strength required to activate the reed switch. MDCG-4-17-28 operates at 17 ~ 28AT. KSK-1A66/3-2030 operates at 20 ~ 30AT (compatible overlap), while KSK-1A35-1015 operates at 10 ~ 15AT (non-overlapping). The operate range must be compatible with the application's magnetic field source.

Q: Can I use KSK-1A35-1015 if my application uses a lower magnetic field?

A: KSK-1A35-1015 has a lower operate range (10 ~ 15AT) than the original part (17 ~ 28AT). If your application's magnetic field falls within 10 ~ 15AT, this substitute is electrically viable but requires surface mount implementation. If the magnetic field is outside this range, the substitute will not function reliably.

Q: What are the voltage and current limits for each part?

A: MDCG-4-17-28: 140V AC / 200V DC, 350mA (AC) / 500mA (DC). KSK-1A66/3-2030: 200V AC/DC, 500mA (AC/DC). KSK-1A35-1015: 200V AC/DC, 1A (AC/DC). All substitutes support the original part's voltage and current requirements with equal or higher ratings.

Q: Are there any temperature range differences?

A: MDCG-4-17-28 operates from -40°C ~ 125°C. Both substitutes extend the upper limit to 130°C, providing a 5°C margin. If your application requires operation above 125°C, the original part may not be suitable, but substitutes provide additional thermal headroom.