5KP45C Transient Voltage Suppressor - Equivalent & Substitute Parts

Part Overview

The 5KP45C is a bidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 45V reverse standoff voltage, 5000W peak pulse power rating, and through-hole P600 axial packaging. The 5KP45C is currently listed as obsolete, necessitating identification of active equivalent and substitute parts that maintain functional compatibility within specified electrical and mechanical parameters.

Key Parameters

Parameter	Value
Manufacturer Part Number	5KP45C
Manufacturer	Littelfuse Inc.
Category	Transient Voltage Suppressors (TVS)
Type	Zener
Bidirectional Channels	1
Voltage - Reverse Standoff (Typ)	45V
Voltage - Breakdown (Min)	47.39V
Voltage - Clamping (Max) @ Ipp	76.34V
Power - Peak Pulse	5000W (5kW)
Operating Temperature	-55°C ~ 175°C (TJ)
Mounting Type	Through Hole
Package / Case	P600, Axial
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the 5KP45C is determined by the following critical parameters:

Voltage Parameters: Reverse standoff voltage (45V nominal), breakdown voltage minimum (47.39V), and clamping voltage maximum (76.34V) define the protection threshold and response characteristics. Substitute parts must operate within these voltage windows to provide equivalent circuit protection.

Power Rating: The 5000W peak pulse power rating establishes the energy dissipation capability. Substitutes with equal or higher power ratings maintain or exceed the original protection capacity.

Electrical Type: Bidirectional zener TVS diode configuration ensures protection against both positive and negative transient events.

Mechanical Compatibility: Through-hole mounting and axial package orientation are required for direct board-level replacement without redesign.

Temperature Range: Operating temperature specification of -55°C to 175°C (TJ) defines the thermal operating envelope.

Substitute parts are grouped into two categories: direct equivalents maintaining identical package and power rating (P600, 5kW), and functional alternatives with different packages and reduced power ratings (DO-201, DO-15, DO-41) that provide equivalent voltage protection for lower-energy applications.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Power - Peak Pulse	Package / Case	Operating Temperature	Product Status
5KP45C	Littelfuse Inc.	45V	47.39V	76.34V	5000W	P600, Axial	-55°C ~ 175°C	Obsolete
5KP45CA	Littelfuse Inc.	45V	50V	72.7V	5000W	P600, Axial	-55°C ~ 175°C	Active
5KP45CE3/TR13	Microchip Technology	45V	50V	80.3V	5000W	P600, Axial	-55°C ~ 175°C	Active
1.5KE47CA	Diotec Semiconductor	40.2V	44.7V	64.8V	1500W	DO-201AA, Axial	-50°C ~ 175°C	Active
1.5KE51CA	Taiwan Semiconductor Corporation	43.6V	48.5V	70.1V	1500W	DO-201AA, Axial	-55°C ~ 175°C	Active
1.5KE56CA	Taiwan Semiconductor Corporation	47.8V	53.2V	77V	1500W	DO-201AA, Axial	-55°C ~ 175°C	Active
P6KE47CA	Diotec Semiconductor	40.2V	44.7V	64.8V	600W	DO-204AC, Axial	-50°C ~ 175°C	Active
P6KE51CA	Taiwan Semiconductor Corporation	43.6V	48.5V	70.1V	600W	DO-204AC, Axial	-55°C ~ 175°C	Active
SA48CA	Taiwan Semiconductor Corporation	48V	53.3V	77.4V	500W	DO-204AC, Axial	-55°C ~ 175°C	Active
P4KE56CA-TP	Micro Commercial Co	47.8V	53.2V	77V	400W	DO-204AL, Axial	-55°C ~ 175°C	Active
1N6124	Semtech Corporation	42.6V	50.4V	80.7V	500W	Axial	-65°C ~ 175°C	Discontinued

Engineering Selection Recommendations

Direct Package Equivalents (P600, 5kW): The 5KP45CA (Littelfuse Inc., active status) and 5KP45CE3/TR13 (Microchip Technology, active status) are direct functional replacements for the obsolete 5KP45C. Both maintain identical package geometry, power rating, and reverse standoff voltage specification. These parts enable direct board-level substitution without circuit redesign or layout modification.

Voltage-Compatible Alternatives (Reduced Power Rating): The 1.5KE series (1.5KE47CA, 1.5KE51CA, 1.5KE56CA) and P6KE series (P6KE47CA, P6KE51CA) provide equivalent voltage protection with reduced power dissipation capacity (1500W and 600W respectively). These parts are suitable for applications where peak pulse energy requirements are lower than the original 5000W specification. The 1.5KE51CA and 1.5KE56CA maintain the full -55°C to 175°C temperature range.

Compact Package Alternatives: The SA48CA and P4KE56CA-TP offer further size reduction with 500W and 400W power ratings respectively, maintaining voltage protection within the 45V to 48V standoff range. These are applicable only where circuit board space constraints and reduced energy dissipation requirements align with application specifications.

Discontinued Parts: The 1N6124 (Semtech Corporation) is listed as discontinued at DiGi Electronics and should not be selected for new designs despite active inventory availability.

Frequently Asked Questions (FAQ)

Q: Can the 5KP45CA directly replace the 5KP45C without any circuit modifications?

A: Yes. The 5KP45CA maintains identical electrical specifications (45V reverse standoff, 5000W power rating), package type (P600 axial), and operating temperature range (-55°C to 175°C). Direct substitution is possible without circuit redesign.

Q: What is the difference between the P600 package (5KP45CA) and the DO-201 package (1.5KE51CA)?

A: Package geometry differs significantly. P600 is a larger through-hole package designed for higher power dissipation. DO-201 is a smaller axial package. Electrical performance is comparable, but physical board layout and thermal management requirements differ. DO-201 packages are suitable only where reduced power dissipation is acceptable.

Q: Are the 1.5KE and P6KE series suitable replacements for the 5KP45C?

A: These series provide equivalent voltage protection (43.6V to 47.8V standoff range) but with significantly reduced power ratings (1500W and 600W versus 5000W). Selection depends on actual circuit energy requirements. If the application requires full 5000W dissipation capacity, these alternatives are unsuitable.

Q: Why is the 1N6124 not recommended despite available inventory?

A: The 1N6124 is listed as discontinued at DiGi Electronics. While current inventory exists, future availability cannot be assured. Active-status parts (5KP45CA, 5KP45CE3/TR13) are preferred for new designs and long-term production requirements.

Q: What are the key electrical parameters that determine substitution compatibility?

A: Reverse standoff voltage (45V nominal), breakdown voltage minimum (47.39V), clamping voltage maximum (76.34V), and power rating (5000W) are the primary determinants. Substitute parts must operate within these voltage windows and maintain or exceed the power dissipation requirement for equivalent circuit protection.

Q: Can a lower-power TVS diode be used if the circuit operates below peak pulse conditions?

A: Potentially, but only if actual circuit transient energy is confirmed to be below the reduced power rating. The 1.5KE and P6KE series are applicable only where measured or calculated peak pulse energy is substantially lower than 5000W. Conservative design practice recommends matching or exceeding the original power specification.

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