C231S Solid State Relay - Equivalent & Substitute Parts

Part Overview

The C231S is a Surface Mount Solid State SPST-NO (1 Form A) relay manufactured by Coto Technology in a 4-SOP package format. This component is rated for 120 mA load current with 0-350V AC/DC switching capability and a 1.37VDC input trigger voltage. The product is currently obsolete, necessitating identification of functionally equivalent alternatives for continued system support and new designs requiring this relay topology.

Substiute Parts

C231S

Coto TechnologyIn Stock: 3079C231S Datasheet

Current PartRFQ

VOR1142M4

Vishay Semiconductor Opto DivisionIn Stock: 10378VOR1142M4 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the obsolete C231S is based on matching critical electrical and mechanical parameters that ensure functional compatibility. The primary substitution criteria are:

Mandatory Matching Parameters:

• Circuit topology (SPST-NO 1 Form A)
• Output type capability (AC, DC switching)
• Input voltage compatibility (nominal 1.36-1.37 VDC range)
• Load voltage rating sufficient for 0-350V operation
• Load current capability equal to or exceeding 120 mA
• Package category (4-SOP surface mount, gull wing termination)

The VOR1142M4 solid state relay from Vishay Semiconductor Opto Division satisfies all these substitution criteria with enhanced performance margins and active product status.

Parameter Comparison

Engineering Selection Recommendations

The VOR1142M4 is the appropriate substitute for the obsolete C231S based on the following engineering factors:

Compliance & Availability: The VOR1142M4 maintains ROHS3 and REACH compliance equivalent to the original component while holding active product status, ensuring sustained supply chain viability and manufacturing support.

Electrical Performance: The substitute meets or exceeds all critical electrical specifications. The input voltage tolerance is equivalent (1.36 VDC vs. 1.37 VDC), load voltage rating is superior (400 V vs. 350 V), and load current capability exceeds the original requirement (140 mA vs. 120 mA). The on-state resistance differential (27 Ohms vs. 24 Ohms) remains within acceptable engineering margins for SPST-NO relay applications.

Mechanical & Packaging: Both components utilize identical circuit topology and surface mount gull wing termination. Package dimensions are equivalent within SMD assembly tolerances (4-SOP 0.180" vs. 0.173"), with standard pick-and-place equipment compatibility maintained. The MSL rating improvement (1 vs. 2) provides superior moisture protection during storage and assembly operations.

Frequently Asked Questions (FAQ)

Q: Can the VOR1142M4 be used as a direct drop-in replacement for the C231S?

A: Yes. Both components share the same SPST-NO circuit topology, surface mount 4-SOP package format with gull wing termination, and input trigger voltage specifications. PCB footprints are compatible within standard SMD tolerance ranges for automated assembly equipment.

Q: How do the input voltage specifications compare?

A: The VOR1142M4 operates at 1.36 VDC compared to the C231S at 1.37 VDC. This 0.01 VDC difference is negligible in practical circuit design and does not affect substitution compatibility.

Q: Is the load voltage rating difference significant?

A: The VOR1142M4 supports 0-400V load voltage versus the C231S at 0-350V. This 50V margin increase provides enhanced design flexibility and safety margin for applications at the upper voltage boundary of the original specification.

Q: What about the load current rating difference of 20 mA?

A: The VOR1142M4 is rated for 140 mA compared to the C231S at 120 mA. This 16.7% margin increase allows the substitute to handle the original load specification with improved thermal headroom and reliability margins. The on-state resistance is slightly higher (27 Ohms vs. 24 Ohms), which remains within acceptable limits for SPST-NO relay switching applications.

Q: Are there compliance concerns with substitution?

A: No. Both components meet ROHS3 and REACH compliance requirements. The VOR1142M4 provides superior moisture sensitivity protection (MSL 1 versus MSL 2), making it suitable for advanced manufacturing environments and extended storage conditions.

Q: Does the 4-SOP package size difference affect assembly?

A: The dimensional difference between 4-SOP 0.173" and 0.180" is standard within SMD manufacturing tolerances. Existing PCB footprints and automated assembly equipment require no modifications for the VOR1142M4 substitution.