Equivalent & Substitute Parts for 5KP45C-B

Part Overview

The 5KP45C-B is a bidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse, rated at 45V reverse standoff with 5000W peak pulse power handling. This component is designed for general-purpose transient voltage protection in through-hole P600 axial package configuration. The part is currently obsolete, making equivalent and substitute parts necessary for ongoing design support and production requirements.

Key Parameters

Parameter	Value
Manufacturer Part Number	5KP45C-B
Manufacturer	Littelfuse
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
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the 5KP45C-B is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff (Typ): 40.2V to 48V range
Voltage - Clamping (Max) @ Ipp: 64.8V to 80.7V range
Power - Peak Pulse: 500W to 5000W
Bidirectional Channels: 1
Type: Zener
Mounting Type: Through Hole
Operating Temperature: -55°C to 175°C (TJ)

Package Compatibility Groups:

P600 Axial Package (direct mechanical equivalent): 5KP45CA, 5KP45CA-B, 5KP45CE3/TR13
DO-201 Axial Package (reduced power rating): 1.5KE47CA, 1.5KE51CA, 1.5KE56CA
DO-15 Axial Package (reduced power rating): P6KE47CA, P6KE51CA, SA48CA
Axial Package (legacy): 1N6124

Substitutes are grouped by package type and power rating capability. Higher power-rated substitutes (5000W) maintain full functional equivalence. Lower power-rated substitutes (1500W, 600W, 500W) are suitable where transient energy levels permit.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Power - Peak Pulse	Package / Case	Product Status	RoHS Status
5KP45C-B	Littelfuse	45V	47.39V	76.34V	5000W	P600, Axial	Obsolete	ROHS3 Compliant
5KP45CA	Littelfuse Inc.	45V	50V	72.7V	5000W	P600, Axial	Active	ROHS3 Compliant
5KP45CA-B	Littelfuse	45V	50V	72.7V	5000W	P600, Axial	Active	ROHS3 Compliant
5KP45CE3/TR13	Microchip Technology	45V	50V	80.3V	5000W	P600, Axial	Active	ROHS3 Compliant
1.5KE47CA	Diotec Semiconductor	40.2V	44.7V	64.8V	1500W	DO-201AA, DO-27, Axial	Active	Not applicable
1.5KE51CA	Taiwan Semiconductor Corporation	43.6V	48.5V	70.1V	1500W	DO-201AA, DO-27, Axial	Active	ROHS3 Compliant
1.5KE56CA	Taiwan Semiconductor Corporation	47.8V	53.2V	77V	1500W	DO-201AA, DO-27, Axial	Active	ROHS3 Compliant
P6KE47CA	Diotec Semiconductor	40.2V	44.7V	64.8V	600W	DO-204AC, DO-15, Axial	Active	ROHS3 Compliant
P6KE51CA	Taiwan Semiconductor Corporation	43.6V	48.5V	70.1V	600W	DO-204AC, DO-15, Axial	Active	ROHS3 Compliant
SA48CA	Taiwan Semiconductor Corporation	48V	53.3V	77.4V	500W	DO-204AC, DO-15, Axial	Active	ROHS3 Compliant
1N6124	Semtech Corporation	42.6V	50.4V	80.7V	500W	Axial	Discontinued at DiGi Electronics	Not Applicable

Engineering Selection Recommendations

Direct Replacement (Same Package, Same Power Rating):

5KP45CA and 5KP45CA-B are active Littelfuse equivalents in P600 package with 5000W power rating and ROHS3 compliance. These provide direct functional substitution with identical mechanical fit.
5KP45CE3/TR13 (Microchip Technology) is an active alternative in P600 package with 5000W rating and ROHS3 compliance, offering equivalent performance with different clamping voltage characteristics.

Alternative Substitutes (Different Package, Reduced Power Rating):

1.5KE series (1.5KE47CA, 1.5KE51CA, 1.5KE56CA) in DO-201 package provide 1500W peak pulse power. These are suitable where transient energy requirements are lower than 5000W.
P6KE series (P6KE47CA, P6KE51CA) in DO-15 package provide 600W peak pulse power. These are suitable for applications with minimal transient energy exposure.
SA48CA in DO-15 package provides 500W peak pulse power with voltage characteristics closest to the original part.

Compliance Considerations:

All active substitutes maintain ROHS3 compliance except 1.5KE47CA (not applicable status).
1N6124 is discontinued and carries not applicable RoHS status; use only if existing inventory is available and regulatory compliance is not required.

Frequently Asked Questions (FAQ)

Q: Can I use a lower power-rated substitute like P6KE51CA instead of 5KP45C-B? A: Yes, if your circuit's transient energy levels are within the 600W limit. The P6KE51CA maintains compatible voltage characteristics (43.6V standoff, 70.1V clamping) but handles lower peak pulse power. Verify your application's actual transient energy requirements before substitution.

Q: What is the difference between 5KP45CA and 5KP45CA-B? A: Both are Littelfuse active equivalents with identical electrical specifications (45V standoff, 5000W power, P600 package). The difference is packaging: 5KP45CA is supplied in Cut Tape (CT), while 5KP45CA-B is supplied in Bulk. Electrical performance is identical.

Q: Why are there different package types listed as substitutes? A: The 5KP45C-B uses P600 axial package. Substitutes in DO-201 and DO-15 packages are physically different but electrically compatible for applications where mechanical fit allows. DO-201 and DO-15 packages are smaller and typically rated for lower power dissipation.

Q: Is 1N6124 still available for use? A: 1N6124 is discontinued at DiGi Electronics and should not be specified for new designs. It remains listed as a historical equivalent but carries discontinued status. Use active alternatives such as 5KP45CA or 5KP45CE3/TR13 instead.

Q: Can I substitute 5KP45CE3/TR13 (Microchip) for the original Littelfuse part? A: Yes. Both maintain 45V standoff, 5000W power rating, P600 package, and ROHS3 compliance. The clamping voltage differs slightly (80.3V vs 76.34V), which is within acceptable tolerance for general-purpose transient suppression applications.

Q: What does "Voltage - Clamping (Max) @ Ipp" mean in substitution context? A: This is the maximum voltage the TVS diode will clamp to when peak pulse current flows through it. Lower clamping voltages provide better protection but may require higher current handling. Substitutes with clamping voltages within 64.8V to 80.7V range are functionally equivalent for the 45V standoff class.

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