20KPA68C-B Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The 20KPA68C-B is a bidirectional Zener-type transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 68V reverse standoff voltage rating and provides peak pulse power dissipation of 20kW. The part is classified as obsolete, necessitating identification of active equivalent and substitute components to maintain design continuity and ensure ongoing component availability for production and repair applications.

Substiute Parts

20KPA68C-B

Littelfuse Inc.In Stock: 110020KPA68C-B Datasheet

Current PartRFQ

20KPA68CA

MDE Semiconductor IncIn Stock: 208520KPA68CA Datasheet

DirectRFQ

20KPA68CA-B

LittelfuseIn Stock: 71720KPA68CA-B Datasheet

DirectRFQ

BZW50-68B

STMicroelectronicsIn Stock: 6239BZW50-68B Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 20KPA68C-B is determined by the following critical parameters:

• Voltage - Reverse Standoff (Typ): 68V (exact match required)
• Bidirectional Channels: 1 (single channel configuration)
• Mounting Type: Through Hole (mechanical compatibility)
• Package / Case: P600 or equivalent axial package (physical fit requirement)
• Type: Zener (functional classification)

Substitute parts must maintain identical reverse standoff voltage and channel configuration to ensure proper circuit protection function. Variations in clamping voltage, peak pulse current, and power dissipation are permissible within the constraints of the application circuit design, provided the component remains capable of transient suppression at the specified voltage level.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (20KPA68CA and 20KPA68CA-B):

The 20KPA68CA and 20KPA68CA-B represent the most direct substitutes for the obsolete 20KPA68C-B. Both maintain identical reverse standoff voltage (68V), peak pulse current (183.6A), and peak pulse power (20kW). Both are active products with ROHS3 compliance. The 20KPA68CA-B is manufactured by Littelfuse, the original manufacturer of the main part, ensuring design continuity. The 20KPA68CA is manufactured by MDE Semiconductor Inc and offers equivalent electrical performance. The primary difference between these substitutes and the main part is the reduced clamping voltage (110V versus 115.5V), which represents a 4.8% reduction and remains within acceptable tolerance for general-purpose transient suppression applications.

Secondary Substitute (BZW50-68B):

The BZW50-68B, manufactured by STMicroelectronics, maintains the 68V reverse standoff voltage and single-channel configuration. This part is designated as manufacturer-recommended and is active. However, this substitute exhibits significant differences in electrical performance: peak pulse current is doubled (382A versus 183.6A), clamping voltage is substantially higher (157V versus 115.5V), and peak pulse power is reduced to 5kW. The package differs (R-6 versus P600), requiring mechanical re-evaluation for board-level integration. This substitute is suitable only for applications where the higher clamping voltage and reduced power dissipation are acceptable within the circuit design constraints.

Compliance and Availability:

All substitute parts maintain ROHS3 compliance, ensuring regulatory alignment with the original component. The 20KPA68CA and 20KPA68CA-B offer superior inventory availability (2035 and 700 units respectively) compared to the obsolete main part (1070 units). The BZW50-68B provides the highest inventory level (6200 units).

Frequently Asked Questions (FAQ)

Q: Can the 20KPA68CA be used as a direct replacement for the 20KPA68C-B?

A: Yes. The 20KPA68CA maintains identical reverse standoff voltage (68V), peak pulse current (183.6A), and peak pulse power (20kW). The clamping voltage is reduced from 115.5V to 110V, a 4.8% difference that is acceptable for general-purpose transient suppression. Both components are Zener-type, single-channel, through-hole mounted devices with ROHS3 compliance.

Q: What is the difference between 20KPA68CA and 20KPA68CA-B?

A: Both parts are electrically identical with 68V reverse standoff voltage, 183.6A peak pulse current, and 110V clamping voltage. The primary difference is manufacturer: 20KPA68CA is manufactured by MDE Semiconductor Inc, while 20KPA68CA-B is manufactured by Littelfuse. The 20KPA68CA-B provides design continuity with the original manufacturer.

Q: Is the BZW50-68B a suitable substitute?

A: The BZW50-68B maintains the 68V reverse standoff voltage and single-channel configuration, making it electrically compatible at the voltage protection level. However, it exhibits higher clamping voltage (157V), doubled peak pulse current (382A), and reduced peak pulse power (5kW). The package differs (R-6 versus P600), requiring mechanical re-evaluation. This substitute is suitable only if the circuit design accommodates these electrical and physical differences.

Q: Are all substitute parts RoHS compliant?

A: Yes. The 20KPA68CA, 20KPA68CA-B, and BZW50-68B are all ROHS3 compliant, matching the compliance status of the original 20KPA68C-B.

Q: What is the impact of the reduced clamping voltage in the 20KPA68CA and 20KPA68CA-B?

A: The clamping voltage reduction from 115.5V to 110V represents a 4.8% decrease. This means the component will clamp transient voltages at a slightly lower threshold. For most general-purpose applications, this difference is within acceptable tolerance. Circuit-specific analysis is required if the application has strict clamping voltage requirements.

Q: Can these parts be used interchangeably on the same PCB?

A: The 20KPA68CA and 20KPA68CA-B can be used interchangeably due to identical electrical specifications and P600 package compatibility. The BZW50-68B uses an R-6 package and requires mechanical re-evaluation for board-level fit and lead compatibility before substitution.

Q: What inventory considerations should guide part selection?

A: The 20KPA68CA offers the highest inventory (2035 units), followed by the BZW50-68B (6200 units), and the 20KPA68CA-B (700 units). For applications requiring immediate availability, the 20KPA68CA is the preferred choice. For design continuity with the original manufacturer, the 20KPA68CA-B is recommended despite lower inventory levels.