3KP120-B Equivalent & Substitute Parts

Part Overview

The 3KP120-B is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse, designed for general-purpose overvoltage protection applications. This part operates with a 120V reverse standoff voltage and provides 3kW peak pulse power dissipation in a through-hole P600 axial package. The 3KP120-B is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Active alternatives with comparable or enhanced electrical characteristics are available from multiple manufacturers.

Substiute Parts

3KP120-B

LittelfuseIn Stock: 6373KP120-B Datasheet

Current PartRFQ

5KP120A-B

Littelfuse Inc.In Stock: 8685KP120A-B Datasheet

DirectRFQ

15KPA120AE3/TR13

Microchip TechnologyIn Stock: 99015KPA120AE3/TR13 Datasheet

MFR RecommendedRFQ

3KP120A-TP

Micro Commercial CoIn Stock: 9563KP120A-TP Datasheet

MFR RecommendedRFQ

5KP120A-E3/54

Vishay General Semiconductor - Diodes DivisionIn Stock: 82005KP120A-E3/54 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 3KP120-B is determined by the following critical parameters:

• Voltage - Reverse Standoff (Typ): 120V (exact match required)
• Voltage - Breakdown (Min): 126V minimum
• Unidirectional Channels: 1 (single channel only)
• Type: Zener diode
• Mounting Type: Through Hole
• Operating Temperature Range: -55°C ~ 175°C minimum
• RoHS Status: ROHS3 Compliant

Substitute parts must maintain identical reverse standoff voltage and unidirectional topology. Variations in clamping voltage, peak pulse current, and power dissipation are acceptable provided the substitute meets or exceeds the original specifications. Package compatibility (P600 or R-6 axial) is required for direct board-level replacement.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts are active products with ROHS3 compliance (where specified), making them suitable for new designs and production environments. The 3KP120-B obsolete status necessitates transition to one of these alternatives.

For direct board-level replacement with identical footprint and power handling, select 3KP120A-TP (Micro Commercial Co) or 5KP120A-B (Littelfuse). Both maintain the original 3kW power rating and 15.5A peak pulse current specification.

For applications requiring enhanced transient protection margin, 5KP120A-B and 5KP120A-E3/54 provide 5kW power dissipation with comparable clamping characteristics. The 15KPA120AE3/TR13 (Microchip Technology) offers maximum protection with 15kW peak pulse power, suitable for high-stress environments.

Package consideration: 3KP120A-TP uses R-6 axial package instead of P600. Verify PCB layout compatibility before selection. All other substitutes use P600 package, ensuring direct mechanical compatibility with the original 3KP120-B footprint.

Frequently Asked Questions (FAQ)

Q: Can I use 5KP120A-B as a direct replacement for 3KP120-B?

A: Yes. The 5KP120A-B maintains the critical 120V reverse standoff voltage, identical operating temperature range, and P600 axial package. It provides enhanced specifications with 5kW power dissipation versus the original 3kW, making it a compatible upgrade.

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

A: Both are through-hole axial packages for TVS diodes. P600 and R-6 have different physical dimensions and lead spacing. Verify your PCB layout supports the selected package before substitution. The 3KP120A-TP uses R-6 package, while the original 3KP120-B uses P600.

Q: Why does 15KPA120AE3/TR13 have higher peak pulse current (78.5A) than the original?

A: The 15KPA120AE3/TR13 is a higher-power variant designed for more demanding transient suppression applications. The increased current rating reflects greater energy absorption capability. It remains compatible with 120V standoff voltage circuits and can be used as a substitute with enhanced protection margins.

Q: Are all substitutes ROHS3 compliant?

A: Four of the five listed substitutes explicitly state ROHS3 compliance. The 3KP120A-TP (Micro Commercial Co) does not specify RoHS status in the provided data. Verify compliance requirements for your application before final selection.

Q: What is the significance of clamping voltage differences?

A: Clamping voltage determines the maximum voltage spike the TVS diode allows across the protected circuit. The original 3KP120-B clamps at 202.65V, while most substitutes clamp at 192-193V. Lower clamping voltage provides tighter protection. All values remain within acceptable ranges for 120V standoff applications.

Q: Can I substitute based on power rating alone?

A: No. Reverse standoff voltage (120V) and unidirectional topology (single channel Zener) are non-negotiable parameters. Power rating, peak pulse current, and clamping voltage can vary, but the core voltage and channel specifications must match the original design intent.