Equivalent & Substitute Parts for 3KP18C-B TVS Diode

Part Overview

The 3KP18C-B is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose voltage clamping applications. This bidirectional Zener diode features an 18V reverse standoff voltage and 30.66V maximum clamping voltage at peak pulse current. The part is classified as obsolete, making equivalent substitute parts necessary for ongoing design support and procurement.

Substiute Parts

3KP18C-B

Littelfuse Inc.In Stock: 8453KP18C-B Datasheet

Current PartRFQ

5KP18CA-B

Littelfuse Inc.In Stock: 7835KP18CA-B Datasheet

DirectRFQ

15KP18CA-TP

Micro Commercial CoIn Stock: 129215KP18CA-TP Datasheet

MFR RecommendedRFQ

15KPA18CAE3/TR13

Microchip TechnologyIn Stock: 98815KPA18CAE3/TR13 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 3KP18C-B is determined by the following critical parameters:

• Reverse standoff voltage: 18V (all substitutes maintain this specification)
• Clamping voltage range: 29.2V to 30.9V (within acceptable tolerance for the application)
• Bidirectional Zener type with single channel configuration
• Through-hole axial mounting (P600 or R-6 package variants)
• Operating temperature range: -55°C to 175°C
• RoHS3 compliance and MSL Level 1 rating

Substitute parts are grouped by manufacturer and product status. Active parts with higher power ratings (5kW and 15kW) provide enhanced performance margins while maintaining electrical compatibility with the original 3KP18C-B specifications.

Parameter Comparison

Engineering Selection Recommendations

5KP18CA-B (Littelfuse Inc.) — Direct replacement with active product status. Maintains P600 axial package compatibility. Provides 67% higher peak pulse current (174.7A vs 102.7A) and 67% higher power rating (5kW vs 3kW) while preserving clamping voltage characteristics. ROHS3 compliant with unlimited MSL rating.

15KP18CA-TP (Micro Commercial Co) — Active substitute with 15kW peak pulse power rating. Uses R-6 axial package variant instead of P600; verify mechanical fit in target application. Clamping voltage of 30.9V remains within acceptable range. ROHS3 and REACH compliant.

15KPA18CAE3/TR13 (Microchip Technology) — Active substitute with highest performance specification: 15kW peak pulse power and 488.7A peak pulse current. Maintains P600 axial package. Supplied in Tape & Reel format. ROHS3 and REACH compliant. Recommended for applications requiring maximum transient protection margin.

All substitutes maintain the 18V reverse standoff voltage, -55°C to 175°C operating temperature range, and RoHS3 compliance required for the original application.

Frequently Asked Questions (FAQ)

Q: Can 5KP18CA-B directly replace 3KP18C-B in existing designs? A: Yes. Both parts share identical reverse standoff voltage (18V), clamping voltage range (29.2V to 30.66V), and P600 axial through-hole package. The 5KP18CA-B is an active product with higher current and power ratings, providing enhanced protection without design modification.

Q: What is the difference between P600 and R-6 packages? A: Both are axial through-hole packages for TVS diodes. P600 and R-6 are different mechanical form factors. Verify mechanical compatibility with your PCB layout before selecting 15KP18CA-TP, which uses the R-6 package.

Q: Why do substitute parts have higher power ratings? A: The 5KP18CA-B (5kW) and 15KP18CA-TP / 15KPA18CAE3/TR13 (15kW) represent higher-performance variants in the same voltage class. Higher power ratings indicate greater transient energy absorption capability while maintaining the same voltage protection threshold.

Q: Are all substitutes RoHS3 compliant? A: Yes. All listed substitutes are ROHS3 compliant with MSL Level 1 (unlimited moisture sensitivity level), matching the original 3KP18C-B specifications.

Q: What is the significance of product status (Obsolete vs Active)? A: The 3KP18C-B is obsolete and no longer manufactured. Active substitutes ensure long-term availability and supply chain continuity for new designs and production runs.

Q: Does clamping voltage variation affect circuit performance? A: Clamping voltage differences are within 1.7V across all substitutes (29.2V to 30.9V). Verify that your circuit design tolerates this range. All parts maintain the 18V reverse standoff voltage, which is the primary protection threshold.