MDCG-4-12-28 Equivalent & Substitute Parts

Part Overview

The MDCG-4-12-28 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 operates within a 12–28 AT (Ampere-Turn) range and is rated for 350mA AC / 500mA DC switching at 140V AC and 200V DC, with a maximum power dissipation of 10W. The part maintains active product status 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-4-12-28

Littelfuse Inc.In Stock: 1041MDCG-4-12-28 Datasheet

Current PartRFQ

KSK-1A35-1015

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

MFR RecommendedRFQ

KSK-1A66-1520

Standex-Meder ElectronicsIn Stock: 1882KSK-1A66-1520 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MDCG-4-12-28 is determined by the following electrical and mechanical criteria:

Primary Substitution Criteria:

• Circuit configuration must remain SPST-NO
• Glass body reed switch type
• Current switching capacity must equal or exceed 350mA AC / 500mA DC
• Voltage switching rating must equal or exceed 140V AC / 200V DC
• Power rating must equal or exceed 10W
• Operate range overlap or compatibility with 12–28 AT specification
• RoHS3 compliance and MSL 1 rating required
• Mounting type compatibility (through-hole preferred; surface mount acceptable with design accommodation)

The two identified substitute parts—KSK-1A35-1015 and KSK-1A66-1520—both satisfy these criteria through elevated current and voltage ratings, ensuring functional equivalence and design margin in applications requiring the MDCG-4-12-28.

Parameter Comparison

Engineering Selection Recommendations

KSK-1A35-1015 (Standex-Meder Electronics)

This substitute provides elevated current capacity (1A AC/DC) and voltage rating (200V AC/DC), exceeding the MDCG-4-12-28 specifications. The 20W power rating offers additional design margin. Surface mount termination requires PCB layout modification; through-hole applications must incorporate an adapter or redesign. Operate range of 10–15 AT is narrower than the original specification. All compliance certifications (RoHS3, REACH Unaffected, MSL 1) are maintained. Product status is active.

KSK-1A66-1520 (Standex-Meder Electronics)

This substitute maintains through-hole mounting compatibility with the MDCG-4-12-28, eliminating mechanical redesign requirements. Current switching (500mA AC/DC) and power rating (10W) match or exceed the original part. Voltage rating (180V AC/DC) is lower than the MDCG-4-12-28 DC specification (200V) but exceeds the AC specification (140V). Operate range of 15–20 AT overlaps the original 12–28 AT range. All compliance certifications (RoHS3, REACH Unaffected, MSL 1) are maintained. Product status is active.

Frequently Asked Questions (FAQ)

Q: Can KSK-1A35-1015 directly replace MDCG-4-12-28 in a through-hole application?

A: No. KSK-1A35-1015 uses surface mount termination (axial, flat), while MDCG-4-12-28 uses through-hole axial termination. Direct PCB substitution is not possible without circuit board redesign or mechanical adapter implementation.

Q: What is the voltage compatibility of KSK-1A66-1520 with MDCG-4-12-28?

A: KSK-1A66-1520 is rated for 180V AC/DC switching. The MDCG-4-12-28 is rated for 140V AC and 200V DC. For AC applications up to 140V, KSK-1A66-1520 is compatible. For DC applications requiring 200V, KSK-1A66-1520 falls 20V short and is not suitable.

Q: Are both substitute parts RoHS3 compliant?

A: Yes. Both KSK-1A35-1015 and KSK-1A66-1520 carry RoHS3 compliance certification, matching the MDCG-4-12-28 environmental standard.

Q: What is the operate range difference between MDCG-4-12-28 and its substitutes?

A: MDCG-4-12-28 operates at 12–28 AT. KSK-1A35-1015 operates at 10–15 AT (narrower, lower threshold). KSK-1A66-1520 operates at 15–20 AT (narrower, mid-range overlap). Applications requiring operation below 15 AT may not function reliably with either substitute.

Q: Do the substitute parts maintain the same switching speed?

A: No. MDCG-4-12-28 has operate time of 0.6 ms and release time of 0.2 ms. Both substitutes (KSK-1A35-1015 and KSK-1A66-1520) have faster switching: 0.5 ms operate time and 0.1 ms release time. Applications sensitive to switching timing must account for this difference.

Q: Are moisture sensitivity ratings equivalent across all three parts?

A: Yes. MDCG-4-12-28, KSK-1A35-1015, and KSK-1A66-1520 all carry MSL 1 (Unlimited) rating, indicating no moisture sensitivity restrictions for storage or handling.