3KP51C Equivalent & Substitute Parts

Part Overview

The 3KP51C is a bidirectional 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 a 3000W peak pulse power rating and operates across the temperature range of -55°C to 175°C. The 3KP51C is classified as obsolete, making identification of suitable substitute parts essential for ongoing design support and production continuity. Equivalent parts must maintain the same voltage protection characteristics and through-hole P600 axial package configuration while meeting current availability and compliance requirements.

Substiute Parts

3KP51C

Littelfuse Inc.In Stock: 9823KP51C Datasheet

Current PartRFQ

5KP51CA

Littelfuse Inc.In Stock: 34625KP51CA Datasheet

DirectRFQ

5KP51CA-TP

Micro Commercial CoIn Stock: 16205KP51CA-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 3KP51C is determined by the following critical parameters:

• Voltage - Reverse Standoff (Typ): Must be 51V to maintain identical protection threshold
• Bidirectional Channels: Must be 1 channel
• Mounting Type: Must be Through Hole
• Package / Case: Must be P600 or equivalent axial configuration
• Operating Temperature Range: Must support -55°C ~ 175°C (TJ)
• Type: Must be Zener-based TVS diode
• RoHS Compliance: Must maintain ROHS3 Compliant status

Substitute parts may vary in peak pulse power rating, clamping voltage, and peak pulse current, provided the reverse standoff voltage and package configuration remain constant. Parts with higher power ratings (5000W or greater) offer enhanced transient protection capability while maintaining backward compatibility with the original 3KP51C footprint and voltage specification.

Parameter Comparison

Engineering Selection Recommendations

5KP51CA (Littelfuse Inc.) is the primary substitute for the obsolete 3KP51C. Both parts maintain identical reverse standoff voltage (51V), bidirectional channel configuration, and through-hole P600 axial package. The 5KP51CA is currently in active production status with 3400 units in stock. The substitute provides enhanced transient protection with 5000W peak pulse power compared to the original 3000W rating, while maintaining ROHS3 compliance and the same operating temperature range. The lower clamping voltage (82.4V vs. 86.52V) provides improved protection margins.

5KP51CA-TP (Micro Commercial Co) is a manufacturer-recommended alternative offering identical electrical performance to the 5KP51CA with 5000W peak pulse power and 51V reverse standoff voltage. This part is actively produced with 1520 units available. The primary distinction is the R-6 axial package configuration versus the P600 package of the original part. Both axial packages are mechanically compatible for through-hole mounting applications, though PCB layout and component spacing may require verification for specific board designs.

Both substitute parts maintain full ROHS3 compliance and support the complete -55°C to 175°C operating temperature range required by the original specification.

Frequently Asked Questions (FAQ)

Q: Can the 5KP51CA directly replace the 3KP51C without circuit modification?

A: Yes. The 5KP51CA maintains the same 51V reverse standoff voltage, bidirectional protection, and through-hole P600 axial package as the 3KP51C. The enhanced 5000W power rating provides superior transient suppression without requiring circuit changes.

Q: What is the difference between P600 and R-6 axial packages?

A: Both P600 and R-6 are through-hole axial package configurations for TVS diodes. The primary difference is the physical package envelope. Both are mechanically compatible with standard through-hole PCB layouts, though specific component spacing and board design should be verified for the R-6 package variant.

Q: Why does the 5KP51CA have a lower clamping voltage than the 3KP51C?

A: The 5KP51CA exhibits a clamping voltage of 82.4V compared to the 3KP51C at 86.52V. This lower clamping voltage represents improved transient suppression performance, providing tighter voltage regulation during overvoltage events while maintaining the same 51V reverse standoff specification.

Q: Are both substitute parts ROHS3 compliant?

A: Yes. Both the 5KP51CA and 5KP51CA-TP are ROHS3 compliant, matching the environmental compliance status of the original 3KP51C.

Q: What is the availability status of substitute parts?

A: The 5KP51CA is in active production with 3400 units in stock. The 5KP51CA-TP is also actively produced with 1520 units available. Both parts offer immediate procurement options for design transitions from the obsolete 3KP51C.