3KP43 Transient Voltage Suppressor - Equivalent & Substitute Parts

Part Overview

The 3KP43 is a unidirectional Zener-type transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 43V reverse standoff voltage rating with a 72.87V maximum clamping voltage and 43.2A peak pulse current capability in a through-hole P600 axial package.

The 3KP43 is classified as obsolete. Identifying suitable substitute components is necessary to maintain design continuity and ensure continued availability for new production builds and field replacements.

Substiute Parts

3KP43

Littelfuse Inc.In Stock: 13023KP43 Datasheet

Current PartRFQ

5KP43A

Littelfuse Inc.In Stock: 34105KP43A Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 3KP43 is based on the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Voltage - Reverse Standoff (Typ): 43V (exact match required)
• Voltage - Clamping (Max) @ Ipp: Must not exceed 72.87V to maintain circuit protection margins
• Current - Peak Pulse (10/1000µs): Must meet or exceed 43.2A
• Power - Peak Pulse: Must meet or exceed 3000W
• Type: Zener, Unidirectional (single channel)
• Operating Temperature Range: -55°C to 175°C minimum

Mechanical Compatibility Criteria:

• Package / Case: P600, Axial (through-hole)
• Mounting Type: Through Hole

Compliance Requirements:

• RoHS3 Compliant

The 5KP43A meets all substitution criteria with enhanced electrical performance characteristics while maintaining identical mechanical and thermal specifications.

Parameter Comparison

Engineering Selection Recommendations

The 5KP43A is a direct substitute for the 3KP43 with superior electrical performance characteristics. Both components are manufactured by Littelfuse Inc. and share identical mechanical specifications, thermal operating range, and RoHS3 compliance status.

The 5KP43A offers enhanced protection capability with 74.6A peak pulse current (versus 43.2A) and 5000W peak pulse power (versus 3000W), while maintaining a lower maximum clamping voltage of 69.4V compared to 72.87V. This combination provides improved transient suppression performance within the same physical footprint and thermal envelope.

The transition from the obsolete 3KP43 to the active 5KP43A ensures long-term component availability and supply chain continuity without requiring circuit redesign or PCB layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the 5KP43A be used as a direct replacement for the 3KP43 in existing designs?

A: Yes. Both components share identical reverse standoff voltage (43V), operating temperature range (-55°C to 175°C), package type (P600 axial), and mounting configuration (through-hole). The 5KP43A provides enhanced electrical performance with higher peak pulse current and power ratings.

Q: What is the key difference between the 3KP43 and 5KP43A?

A: The primary difference is power dissipation capability. The 5KP43A is rated for 5000W peak pulse power compared to 3000W for the 3KP43. The 5KP43A also features a lower maximum clamping voltage (69.4V versus 72.87V), providing tighter voltage regulation during transient events.

Q: Are there any PCB layout or circuit modifications required when substituting the 5KP43A for the 3KP43?

A: No. Both components use the P600 axial package with identical pin spacing and through-hole mounting requirements. No PCB layout changes are necessary.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the 3KP43 and 5KP43A are ROHS3 compliant and carry identical environmental and regulatory certifications.

Q: Why is the 3KP43 obsolete?

A: The 3KP43 has been discontinued by Littelfuse Inc. The 5KP43A represents the current active product offering with equivalent electrical specifications and enhanced performance characteristics.

Q: What is the difference between the 3KP and 5KP series?

A: The 5KP series represents an enhanced generation of TVS diodes with higher power dissipation ratings (5000W versus 3000W for the 3KP series). Both series maintain the same voltage ratings and package configurations within their respective voltage classes.