FSM Tactile Switch SPST-NO Equivalent & Substitute Parts

Part Overview

The FSM is a tactile switch manufactured by TE Connectivity ALCOSWITCH Switches, configured as a SPST-NO (Single Pole Single Throw Normally Open) device rated for 0.05A at 12VDC. This switch features top actuation, through-hole mounting, and a rectangular button actuator with 5.00mm height above the PCB. The FSM is classified as obsolete, making identification of equivalent and substitute parts necessary for ongoing design support and component procurement.

Substiute Parts

FSM

TE Connectivity ALCOSWITCH SwitchesIn Stock: 964FSM Datasheet

Current PartRFQ

FSMH

TE Connectivity ALCOSWITCH SwitchesIn Stock: 78148FSMH Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FSM tactile switch is determined by strict equivalence across the following critical parameters:

Mandatory Equivalence Parameters:

• Circuit configuration (SPST-NO)
• Switch function (Off-Mom momentary operation)
• Actuator type (Rectangular button)
• Mounting type (Through hole)
• Actuator height (5.00mm)
• Outline dimensions (6.00mm x 3.50mm)
• Termination style (PC pin)
• Operating force (130gf)
• Switch travel (0.25mm)
• Actuator material (PBT)

Allowable Variation Parameters:

• Contact rating voltage (12VDC to 24VDC)
• Operating temperature range (within specified limits)
• Mechanical life (20,000 to 100,000 cycles)
• Product status (obsolete to active)
• Compliance certifications (RoHS, REACH)

The FSMH substitute part maintains all mandatory equivalence parameters while offering enhanced electrical rating (24VDC), extended mechanical life (100,000 cycles), and active product status with RoHS3 compliance.

Parameter Comparison

Engineering Selection Recommendations

The FSMH tactile switch serves as a direct substitute for the obsolete FSM model. Both components share identical mechanical and functional characteristics, including circuit configuration, actuator geometry, mounting interface, and operating force specifications.

The FSMH offers the following advantages over the FSM:

Product Status: The FSMH maintains active product status with established supply chain availability, whereas the FSM is classified as obsolete and subject to discontinuation.

Compliance: The FSMH is certified RoHS3 compliant, meeting current regulatory requirements for electronic component manufacturing and distribution in regulated markets.

Electrical Rating: The FSMH is rated for 0.05A at 24VDC, providing higher voltage capability than the FSM's 12VDC rating. This enhanced rating accommodates applications requiring higher supply voltages while maintaining the same current capacity.

Mechanical Durability: The FSMH specifies 100,000 mechanical cycles compared to the FSM's 20,000 cycles, indicating extended operational life under repeated actuation.

Operating Temperature: The FSMH operates across -35°C to 85°C, compared to the FSM's -40°C to 85°C range. The FSMH's lower temperature limit is 5°C higher, which remains suitable for standard industrial and commercial applications.

Selection of the FSMH is appropriate for new designs and replacement applications where the FSM is no longer available.

Frequently Asked Questions (FAQ)

Q: Can the FSMH replace the FSM in existing designs without PCB modification?

A: Yes. The FSMH maintains identical mechanical dimensions (6.00mm x 3.50mm outline, 5.00mm actuator height), through-hole mounting configuration, and PC pin termination style. Direct PCB substitution is possible without layout changes.

Q: What is the significance of the voltage rating difference between FSM (12VDC) and FSMH (24VDC)?

A: The contact rating indicates the maximum voltage at which the switch contacts are rated to operate safely. The FSMH's 24VDC rating provides compatibility with higher voltage supply systems. If the original design operates at 12VDC or lower, the FSMH remains fully compatible and operates within its rated specifications.

Q: Does the FSMH's higher mechanical life rating (100,000 cycles vs. 20,000 cycles) affect circuit behavior?

A: No. Mechanical life rating reflects the durability and expected operational lifespan under repeated actuation. Both parts maintain identical switch travel (0.25mm), operating force (130gf), and electrical characteristics. The higher cycle rating indicates extended component longevity.

Q: Are there packaging differences between FSM and FSMH?

A: The FSM is listed with packaging designation "-" (not specified), while the FSMH is supplied in bulk packaging. Both components are identical in form factor and function; packaging differences relate only to order quantity and delivery format.

Q: Is the FSMH suitable for applications requiring the FSM's -40°C lower operating temperature limit?

A: The FSMH operates from -35°C to 85°C. Applications requiring operation below -35°C would fall outside the FSMH's specified operating range. For such applications, alternative components with extended low-temperature ratings must be evaluated.

Q: What compliance certifications apply to the FSMH?

A: The FSMH is RoHS3 compliant and REACH unaffected. Both certifications confirm compliance with current environmental and hazardous substance regulations applicable to electronic components in regulated markets.

Q: Can the FSM and FSMH be used interchangeably in the same circuit?

A: Yes, within the FSM's original voltage specification. Both components share identical circuit configuration (SPST-NO), switch function (Off-Mom), and electrical characteristics at their respective rated voltages. The FSMH's higher voltage rating does not create incompatibility when used in lower voltage applications.