LS71C2-T Equivalent & Substitute Parts

Part Overview

The LS71C2-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 top-actuated surface mount applications with a compact 3.00mm x 2.60mm footprint and 0.40mm actuator height. The product is currently obsolete, necessitating identification of functionally equivalent alternatives for ongoing design requirements and production continuity.

Substiute Parts

LS71C2-T

CitizenIn Stock: 842LS71C2-T Datasheet

Current PartRFQ

KMT221NG HF LFS

C&KIn Stock: 53942KMT221NG HF LFS Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The KMT221NG HF LFS manufactured by C&K qualifies as a functional substitute for the LS71C2-T based on the following alignment of critical parameters:

Matching Parameters:

• Circuit configuration: SPST-NO
• Switch function: Off-Mom (Momentary)
• Mounting type: Surface Mount
• Actuator orientation: Top Actuated
• Outline dimensions: 3.00mm x 2.60mm (identical footprint)
• Operating force: 160gf (identical actuation force)
• Moisture sensitivity level: 1 (Unlimited)
• RoHS compliance status: Both compliant

Enhanced Specifications: The KMT221NG HF LFS provides higher electrical ratings (0.05A @ 32VDC versus 0.02A @ 12VDC), extended mechanical life (150,000 cycles versus 100,000 cycles), and defined operating temperature range (-40°C ~ 85°C). These enhancements ensure compatibility with the original application while offering improved performance margins.

Parameter Comparison

Engineering Selection Recommendations

The KMT221NG HF LFS is suitable for direct substitution in applications currently utilizing the LS71C2-T. The substitute part maintains identical circuit topology, actuator orientation, and mechanical footprint while providing enhanced electrical performance and extended mechanical life. Both components achieve RoHS compliance and unlimited moisture sensitivity rating, ensuring regulatory alignment.

The primary consideration for implementation is the increased actuator height (0.65mm versus 0.40mm) and termination style transition from SMD Tab to Gull Wing. These mechanical differences require PCB layout verification to confirm clearance and soldering process compatibility. The substitute part's active product status ensures long-term availability and supply chain continuity compared to the obsolete original component.

Frequently Asked Questions (FAQ)

Q: Can the KMT221NG HF LFS directly replace the LS71C2-T without PCB modifications?

A: The identical 3.00mm x 2.60mm footprint and top-actuated orientation enable direct placement. However, the increased actuator height (0.65mm versus 0.40mm) and different termination style (Gull Wing versus SMD Tab) require verification of PCB clearance and reflow soldering parameters.

Q: What is the impact of the higher contact rating (0.05A @ 32VDC) on circuit design?

A: The substitute part's enhanced electrical rating provides additional performance margin for the original application rated at 0.02A @ 12VDC. No circuit modifications are required; the substitute operates safely within the original electrical specifications.

Q: How does the switch travel difference (0.13mm versus 0.15mm) affect tactile feedback?

A: Both components operate at identical 160gf actuation force. The minimal switch travel difference (0.02mm) does not alter the functional tactile response or user experience in momentary switch applications.

Q: What packaging considerations apply when transitioning from LS71C2-T to KMT221NG HF LFS?

A: The original component uses bulk packaging, while the substitute is supplied in Tape & Reel format. This packaging difference improves handling efficiency and component traceability for production environments but requires compatible pick-and-place equipment.

Q: Are there compliance differences between the two components?

A: Both components are RoHS compliant. The substitute achieves ROHS3 compliance, representing a more recent regulatory standard. Both maintain REACH Unaffected status and identical ECCN/HTSUS classifications.

Q: What is the mechanical life advantage of the substitute part?

A: The KMT221NG HF LFS provides 150,000 cycles of mechanical life compared to 100,000 cycles for the LS71C2-T, representing a 50% improvement in durability for high-cycle applications.