CT334 Solid State Relay SPST-NO 180mA 0-200V

Part Overview

The CT334 is a solid state relay (SSR) manufactured by Coto Technology in the COTOMOS™ series. It features a SPST-NO (1 Form A) configuration with dual channels in an 8-DIP package rated for 180mA load current at 0-200V. The product status is listed as obsolete, necessitating identification of functionally equivalent substitute components for procurement and design continuity.

Substiute Parts

CT334

Coto TechnologyIn Stock: 1206CT334 Datasheet

Current PartRFQ

VOR2121A8

Vishay Semiconductor Opto DivisionIn Stock: 1014VOR2121A8 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The VOR2121A8 by Vishay Semiconductor Opto Division is identified as a direct functional equivalent. Substitution eligibility is determined by the following critical electrical and mechanical parameters:

Substitution Criteria:

• Circuit configuration: SPST-NO (1 Form A) x 2
• Package type: 8-DIP (0.300", 7.62mm)
• Mounting method: Through Hole
• Input control voltage: 1.36VDC (equivalent to 1.37VDC within component tolerance)
• Output capability: AC and DC switching
• Load current rating: 200mA (exceeds minimum 180mA requirement)
• Load voltage range: 0V ~ 250V (exceeds minimum 0V ~ 200V requirement)
• Termination style: PC Pin

The VOR2121A8 meets or exceeds all critical electrical parameters while maintaining identical mechanical compatibility, enabling direct substitution in existing board designs.

Parameter Comparison

Engineering Selection Recommendations

The VOR2121A8 is the designated substitute for the obsolete CT334. Selection is supported by the following factors:

Product Availability: The VOR2121A8 maintains Active status with documented inventory, whereas the CT334 is obsolete, making procurement of original devices progressively unavailable.

Compliance & Certifications: Both components are ROHS3 Compliant, meeting environmental regulatory requirements. The VOR2121A8 offers improved moisture sensitivity (MSL 1 vs. MSL 2), extending shelf life and handling flexibility.

Electrical Compatibility: The VOR2121A8 exceeds the CT334 in load current (200mA vs. 180mA) and load voltage range (0-250V vs. 0-200V). Input control voltage remains equivalent (1.36VDC vs. 1.37VDC). On-state resistance differential (15Ω vs. 8Ω) introduces minimal impact in typical applications where the relay serves as a switching element rather than a precision analog component.

Mechanical Compatibility: Identical package footprint (8-DIP 0.300"), pin configuration, and through-hole mounting enable direct board-level substitution without layout modification.

Frequently Asked Questions (FAQ)

Q: Can the VOR2121A8 directly replace the CT334 without board redesign? A: Yes. Both components share identical package geometry (8-DIP 0.300"), pin pitch, and through-hole termination style, enabling direct substitution on existing printed circuit board assemblies.

Q: Are the input voltage specifications compatible? A: The input specifications are functionally equivalent. The CT334 requires 1.37VDC while the VOR2121A8 requires 1.36VDC. This difference is within standard component manufacturing tolerance and poses no compatibility issue in practical applications.

Q: How do the load current and voltage ratings compare? A: The VOR2121A8 provides superior electrical performance. It is rated for 200mA load current versus the CT334's 180mA, and accommodates load voltages from 0V to 250V compared to the CT334's 0V to 200V specification. Applications designed for the CT334 operate safely within the VOR2121A8's performance envelope.

Q: What is the significance of the on-state resistance difference? A: The VOR2121A8 has a maximum on-state resistance of 15Ω versus the CT334's 8Ω. In switching applications where the relay operates in fully on or fully off states, this difference has negligible impact. Applications requiring precise analog switching or minimal voltage drop across the relay element should evaluate the resistance specification against circuit requirements.

Q: Are there compliance or regulatory differences between the two components? A: Both components are ROHS3 compliant. The VOR2121A8 offers improved moisture handling with MSL 1 (unlimited shelf life) compared to the CT334's MSL 2 (1-year shelf life), providing operational and storage advantages.

Q: What circuit configurations are available in both components? A: Both the CT334 and VOR2121A8 provide dual SPST-NO (1 Form A) channels within the same 8-DIP package, maintaining identical functional circuit architecture for simultaneous control of two independent load circuits.