3KP26-B Transient Voltage Suppressor Diode - Equivalent & Substitute Parts

Part Overview

The 3KP26-B is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 26V reverse standoff voltage with a 44.21V maximum clamping voltage and 71.3A peak pulse current capability in a P600 axial through-hole package. The 3KP26-B is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across voltage ratings, clamping characteristics, and thermal operating ranges while accommodating different packaging formats and manufacturer specifications.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	26	V
Voltage - Breakdown (Min)	27.36	V
Voltage - Clamping (Max) @ Ipp	44.21	V
Current - Peak Pulse (10/1000µs)	71.3	A
Power - Peak Pulse	3000	W
Operating Temperature Range	-55 to 175	°C
Mounting Type	Through Hole	—
Package / Case	P600, Axial	—
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution eligibility for the 3KP26-B is determined by the following critical parameters:

Voltage Compatibility: All substitute parts must maintain a 26V reverse standoff voltage (Typ) with breakdown voltages between 27.36V and 29.04V to ensure consistent circuit protection thresholds.

Clamping Voltage: Substitute parts must have maximum clamping voltages at Ipp between 42.1V and 44.21V to limit transient overvoltage exposure within acceptable circuit design margins.

Peak Pulse Current: Substitute parts must support peak pulse currents of 71.3A or greater to handle the same transient energy levels as the original component.

Power Dissipation: Substitute parts must have peak pulse power ratings of 3000W or greater to safely dissipate transient energy without thermal degradation.

Thermal Operating Range: All substitute parts must support the -55°C to 175°C operating temperature range to maintain performance across industrial and commercial applications.

Package and Mounting: Substitute parts are grouped by package type (P600 axial, R-6 axial, or DO-15 axial) to accommodate different PCB layouts and assembly processes. Parts with different packages remain functionally equivalent if electrical parameters align.

Compliance: All substitute parts must maintain ROHS3 compliance and general-purpose application classification.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Breakdown Min (V)	Voltage - Clamping Max @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temp (°C)	Package / Case	Product Status
3KP26-B	Littelfuse Inc.	26	27.36	44.21	71.3	3000	-55 to 175	P600, Axial	Obsolete
5KP26A-B	Littelfuse Inc.	26	28.9	42.1	121.1	5000	-55 to 175	P600, Axial	Active
15KPA26AE3/TR13	Microchip Technology	26	29.04	44	343.2	15000	-55 to 175	P600, Axial	Active
15KPA26E3/TR13	Microchip Technology	26	27.38	—	—	15000	-55 to 175	P600, Axial	Active
3KP26A-TP	Micro Commercial Co	26	28.9	42.1	71.3	3000	-55 to 175	R-6, Axial	Active
5KP26A-E3/54	Vishay General Semiconductor - Diodes Division	26	28.9	42.1	119	5000	-55 to 175	P600, Axial	Active
5KP26A-G	Comchip Technology	26	28.9	42.1	118.76	5000	-55 to 150	R-6, Axial	Active
5KP26AHE3/54	Vishay General Semiconductor - Diodes Division	26	28.9	42.1	119	5000	-55 to 175	P600, Axial	Active
5KP26AHE3/73	Vishay General Semiconductor - Diodes Division	26	28.9	42.1	119	5000	-55 to 175	P600, Axial	Active
P5KE26A-AP	Micro Commercial Co	26	28.9	42.1	11.9	500	-65 to 175	DO-15, Axial	Active
P5KE26A-BP	Micro Commercial Co	26	28.9	42.1	11.9	500	-65 to 175	DO-15, Axial	Active

Engineering Selection Recommendations

Direct Replacement (P600 Package, Equivalent Power Rating)

The 3KP26A-TP (Micro Commercial Co) provides the closest functional match to the 3KP26-B with identical peak pulse current (71.3A) and power dissipation (3000W). This part maintains the same voltage specifications and operating temperature range but uses an R-6 axial package instead of P600. Selection of this part requires PCB layout verification to confirm package compatibility.

Higher Power Capability Substitutes (P600 Package)

The 5KP26A-B (Littelfuse Inc.), 5KP26A-E3/54 (Vishay), 5KP26AHE3/54 (Vishay), and 5KP26AHE3/73 (Vishay) all provide enhanced peak pulse current (119A to 121.1A) and power dissipation (5000W) while maintaining the 26V voltage class and P600 axial package format. These parts are active products with full ROHS3 compliance and support the complete -55°C to 175°C operating range. The Vishay automotive-qualified variants (5KP26AHE3/54 and 5KP26AHE3/73) include AEC-Q101 certification for applications requiring automotive-grade reliability.

Maximum Protection Capability (P600 Package)

The 15KPA26AE3/TR13 and 15KPA26E3/TR13 (Microchip Technology) deliver the highest peak pulse current (343.2A) and power dissipation (15000W) within the 26V voltage class. These parts are supplied in tape and reel packaging and are suitable for applications requiring enhanced transient protection margins. The 15KPA26AE3/TR13 provides complete electrical parameter specification, while 15KPA26E3/TR13 has limited clamping voltage and peak current data.

Lower Power Applications (DO-15 Package)

The P5KE26A-AP and P5KE26A-BP (Micro Commercial Co) are suitable only for applications with reduced transient energy requirements, featuring 11.9A peak pulse current and 500W power dissipation. These parts use the DO-15 axial package and are not recommended as direct replacements for the 3KP26-B due to significantly lower current and power handling capabilities.

Temperature Consideration

The 5KP26A-G (Comchip Technology) operates to 150°C maximum junction temperature, which is 25°C lower than the 3KP26-B specification. This part is suitable only for applications where the maximum operating temperature does not exceed 150°C.

Frequently Asked Questions (FAQ)

Q: Can the 5KP26A-B directly replace the 3KP26-B?

A: The 5KP26A-B is electrically compatible with the 3KP26-B, maintaining the same 26V voltage class, clamping voltage range (42.1V vs. 44.21V), and operating temperature span. The 5KP26A-B provides higher peak pulse current (121.1A vs. 71.3A) and power dissipation (5000W vs. 3000W), making it suitable for the same applications with enhanced protection capability. Both parts use the P600 axial package. The 5KP26A-B is an active product from Littelfuse Inc., eliminating obsolescence concerns.

Q: What is the difference between the Vishay 5KP26A-E3/54 and 5KP26AHE3/54?

A: Both parts share identical electrical specifications (26V standoff, 42.1V clamping, 119A peak pulse, 5000W power) and P600 axial packaging. The 5KP26AHE3/54 and 5KP26AHE3/73 variants include automotive-grade qualification (AEC-Q101) and are designated for applications requiring automotive reliability standards. The standard 5KP26A-E3/54 is suitable for general-purpose industrial applications.

Q: Why are the Microchip 15KPA26 parts listed as substitutes if they have much higher current ratings?

A: The 15KPA26AE3/TR13 and 15KPA26E3/TR13 meet all substitution criteria: 26V reverse standoff voltage, clamping voltage within acceptable range (44V), -55°C to 175°C operating temperature, P600 axial package, and ROHS3 compliance. Higher current and power ratings do not disqualify a part from substitution; they indicate enhanced protection capability. These parts are suitable for applications where additional transient energy margin is beneficial.

Q: Can the P5KE26A-AP or P5KE26A-BP replace the 3KP26-B?

A: These parts are not recommended as direct replacements. While they maintain the 26V voltage class and DO-15 axial package, they provide only 11.9A peak pulse current and 500W power dissipation compared to the 3KP26-B specification of 71.3A and 3000W. These lower-power variants are suitable only for applications with significantly reduced transient energy requirements.

Q: What packaging considerations apply when selecting a substitute?

A: The 3KP26-B uses a P600 axial package. Substitute parts are available in P600 (direct fit), R-6 axial (similar form factor with potential PCB layout differences), and DO-15 axial (smaller package, lower power rating). Package selection depends on PCB layout constraints and available board space. P600 and R-6 packages are mechanically similar and typically interchangeable with minor layout adjustments. DO-15 packages are significantly smaller and require different mounting hole spacing.

Q: Are all substitute parts ROHS3 compliant?

A: All listed substitute parts maintain ROHS3 compliance, consistent with the 3KP26-B specification. This ensures compatibility with environmental and regulatory requirements across industrial, commercial, and automotive applications.

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