SMCJ440 Equivalent & Substitute Parts Reference

Part Overview

The SMCJ440 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose transient voltage protection applications. This component features a 440V reverse standoff voltage rating and is housed in a DO-214AB surface mount package. The SMCJ440 is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and procurement continuity.

Substiute Parts

SMCJ440

Littelfuse Inc.In Stock: 1105SMCJ440 Datasheet

Current PartRFQ

SMCJ440A

MeritekIn Stock: 26234SMCJ440A Datasheet

MFR RecommendedRFQ

SMCJ440A

MeritekIn Stock: 26234SMCJ440A Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMCJ440 is determined by the following critical electrical and mechanical parameters:

• Voltage Rating Class: Reverse standoff voltage of 440V ±tolerance
• Peak Pulse Current: 2.1A capability at 10/1000µs pulse profile
• Clamping Voltage Performance: Maximum clamping voltage at peak pulse current
• Package Compatibility: DO-214AB (SMC) surface mount form factor
• Thermal Operating Range: -55°C to 150°C junction temperature capability
• Diode Type: Unidirectional Zener configuration

The SMCJ440A from Meritek meets all substitution criteria within the allowed parameter tolerances for this product category.

Parameter Comparison

Engineering Selection Recommendations

The SMCJ440A (Meritek) is a direct functional substitute for the obsolete SMCJ440 (Littelfuse). Both components share identical reverse standoff voltage, peak pulse current rating, power dissipation capability, thermal operating range, and package form factor. The SMCJ440A maintains active product status and is ROHS3 compliant with unlimited moisture sensitivity rating, ensuring long-term supply availability and manufacturing compatibility.

The SMCJ440A exhibits a lower maximum clamping voltage (713V versus 748.65V) and higher minimum breakdown voltage (492V versus 465.75V), both of which represent improved transient suppression performance within the 440V voltage class specification.

Frequently Asked Questions (FAQ)

Q: Can the SMCJ440A directly replace the SMCJ440 in existing designs?

A: Yes. Both components are unidirectional Zener TVS diodes with identical reverse standoff voltage (440V), peak pulse current (2.1A), power rating (1500W), operating temperature range (-55°C to 150°C), and DO-214AB surface mount package. Electrical performance differences fall within acceptable substitution parameters for the 440V voltage class.

Q: What are the key differences between these two parts?

A: The primary differences are manufacturer (Littelfuse versus Meritek) and clamping voltage performance. The SMCJ440A provides lower clamping voltage (713V) compared to the SMCJ440 (748.65V), which represents superior transient suppression. The SMCJ440A also has a higher minimum breakdown voltage (492V versus 465.75V).

Q: Are both parts RoHS compliant?

A: Yes. Both the SMCJ440 and SMCJ440A are ROHS3 compliant with MSL rating of 1 (Unlimited), meeting current environmental and manufacturing standards.

Q: What is the significance of the DO-214AB package?

A: The DO-214AB (SMC) is a surface mount package standard for small signal diodes and TVS devices. Both parts use this identical package, ensuring mechanical and thermal compatibility on PCB layouts without redesign requirements.

Q: Why is the SMCJ440 listed as obsolete?

A: Obsolete status indicates the part is no longer manufactured by Littelfuse. The SMCJ440A from Meritek provides equivalent functionality with active product status and established supply chain availability.