3KP51A Equivalent & Substitute Parts

Part Overview

The 3KP51A is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 51V reverse standoff voltage with an 82.4V maximum clamping voltage and 36.4A peak pulse current capability in a P600 axial through-hole package. The 3KP51A is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing design support and component procurement.

Substiute Parts

3KP51A

Littelfuse Inc.In Stock: 8673KP51A Datasheet

Current PartRFQ

5KP51A

LittelfuseIn Stock: 42695KP51A Datasheet

DirectRFQ

3KP51A-TP

Micro Commercial CoIn Stock: 7773KP51A-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 3KP51A is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

• Voltage - Reverse Standoff: 51V (exact match required)
• Voltage - Clamping (Max) @ Ipp: 82.4V (exact match required)
• Voltage - Breakdown (Min): 56.7V (exact match required)
• Type: Zener, Unidirectional (1 channel)
• Operating Temperature Range: -55°C ~ 175°C (TJ)
• Mounting Type: Through Hole
• Package Compatibility: P600 or R-6 axial packages

Secondary Consideration:

• Current - Peak Pulse (10/1000µs): Substitute parts may exceed the 36.4A specification, provided all primary electrical parameters match exactly.
• Power - Peak Pulse: Substitute parts may exceed the 3000W specification, provided all primary electrical parameters match exactly.

Parameter Comparison

Engineering Selection Recommendations

5KP51A (Littelfuse): This substitute is the preferred option for direct replacement of the obsolete 3KP51A. Both components are manufactured by Littelfuse, share identical voltage specifications (51V standoff, 82.4V clamping), and maintain the same operating temperature range. The 5KP51A is currently in active production status with higher peak pulse current (61.9A) and power dissipation (5000W), providing enhanced performance margin. Both components are ROHS3 compliant with MSL rating of 1. The P600 axial package ensures mechanical compatibility with existing PCB layouts.

3KP51A-TP (Micro Commercial Co): This substitute provides an alternative source from Micro Commercial Co with identical electrical specifications to the original 3KP51A (51V standoff, 82.4V clamping, 36.4A peak pulse, 3000W power). The component is in active production status. The R-6 axial package is mechanically compatible with through-hole mounting, though PCB footprint verification is required to confirm dimensional compatibility with the original P600 package design.

Frequently Asked Questions (FAQ)

Q: Can the 5KP51A replace the 3KP51A in all applications? A: Yes. The 5KP51A maintains identical voltage specifications (51V standoff, 82.4V clamping) and operating temperature range (-55°C to 175°C). The higher peak pulse current (61.9A vs 36.4A) and power dissipation (5000W vs 3000W) provide additional performance margin without affecting circuit compatibility.

Q: What is the difference between the P600 and R-6 packages? A: Both are axial through-hole packages for TVS diodes. The P600 is the original package for the 3KP51A, while the R-6 is used for the 3KP51A-TP. Physical dimensions may differ; PCB footprint verification is required before substitution to ensure mechanical fit.

Q: Are all substitute parts RoHS compliant? A: The 5KP51A is ROHS3 compliant. The 3KP51A-TP RoHS compliance status is not specified in available documentation and should be verified with the manufacturer before procurement for applications requiring RoHS certification.

Q: Why is the 3KP51A classified as obsolete? A: The 3KP51A is no longer in active production by Littelfuse. The 5KP51A serves as the active production equivalent with superior electrical performance characteristics.

Q: Can I use a substitute part with higher power rating? A: Yes. The 5KP51A with 5000W peak pulse power rating is a valid substitute for the 3KP51A (3000W). Higher power rating indicates greater transient energy handling capability and does not compromise circuit compatibility when all voltage specifications remain identical.