LS127C4D2-T Equivalent & Substitute Parts

Part Overview

The LS127C4D2-T is a tactile switch manufactured by Citizen, classified as SPST-NO (Single Pole Single Throw - Normally Open) with a contact rating of 0.02A at 12VDC. This component is designed for surface mount applications with top actuation and SMD tab termination. The product status is Obsolete, necessitating identification of functionally equivalent alternatives to support system continuity and procurement requirements.

Substiute Parts

LS127C4D2-T

CitizenIn Stock: 1328LS127C4D2-T Datasheet

Current PartRFQ

KXT 331 LHS

C&KIn Stock: 47291KXT 331 LHS Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The KXT 331 LHS from C&K is identified as a substitute for the LS127C4D2-T based on functional equivalence across critical electrical and mechanical parameters. The substitution is valid where the following conditions are met:

Common Electrical Parameters:

• Circuit configuration: SPST-NO
• Switch function: Off-Mom (Momentary)
• Contact rating: 0.02A (KXT 331 LHS rated at 15VDC, exceeding the 12VDC requirement)

Common Mechanical Parameters:

• Mounting type: Surface Mount
• Actuator orientation: Top Actuated
• Termination style: SMD (SMT) Tab
• Operating force: 240gf (identical)
• Actuator height: 0.60mm (identical)

Substitution Limitations:

• Outline dimensions differ (3.00mm x 2.00mm vs. 3.20mm x 2.00mm), requiring PCB layout verification
• Switch travel differs (0.13mm vs. 0.15mm)
• Mechanical life rating differs (500,000 vs. 300,000 cycles)

Parameter Comparison

Engineering Selection Recommendations

The KXT 331 LHS qualifies as a direct functional substitute for the obsolete LS127C4D2-T based on electrical and mechanical compatibility. The KXT 331 LHS offers the following advantages:

• Product Status: Active product status ensures long-term availability and supply chain continuity.
• Compliance: Both parts maintain REACH Unaffected and identical Moisture Sensitivity Level (MSL 1) classifications, with the KXT 331 LHS meeting ROHS3 Compliance.
• Contact Rating: The 15VDC rating of the KXT 331 LHS provides superior voltage headroom for 12VDC applications.
• Mechanical Life: The 500,000-cycle rating of the KXT 331 LHS exceeds the original 300,000-cycle specification.

Design Consideration: Verification of PCB layout compatibility is required due to outline dimension differences (3.20mm x 2.00mm versus 3.00mm x 2.00mm).

Frequently Asked Questions (FAQ)

Q: Can the KXT 331 LHS replace the LS127C4D2-T in existing designs? A: Yes, the KXT 331 LHS is electrically compatible. However, PCB layout must be verified due to the 0.20mm difference in the X-dimension (3.20mm vs. 3.00mm). Footprint adjustment may be necessary.

Q: Does the voltage rating difference affect compatibility? A: No. The KXT 331 LHS is rated for 0.02A @ 15VDC, which exceeds the LS127C4D2-T requirement of 0.02A @ 12VDC. The higher voltage rating is suitable for lower-voltage applications.

Q: Are there differences in actuator characteristics? A: Both parts share identical operating force (240gf) and actuator height (0.60mm). Switch travel differs slightly (0.13mm vs. 0.15mm), which is negligible for most tactile switching applications.

Q: What are the packaging options for the KXT 331 LHS? A: The KXT 331 LHS is supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes.

Q: Are both parts compliant with environmental regulations? A: Yes. Both parts maintain REACH Unaffected status and Moisture Sensitivity Level 1 (Unlimited). The KXT 331 LHS meets ROHS3 Compliance, exceeding the original RoHS Compliant specification.

Q: What is the mechanical life difference impact? A: The KXT 331 LHS offers 500,000 mechanical cycles versus the original 300,000 cycles. This higher rating provides additional operational margin and extended component lifetime.