SA33C Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA33C is a 33V Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in through-hole applications. This component features a DO-204AC (DO-15) axial package with a peak pulse power rating of 500W and peak pulse current of 9.6A. The SA33C is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and procurement.

Substiute Parts

SA33C

Littelfuse Inc.In Stock: 1040SA33C Datasheet

Current PartRFQ

SA33CA

Fairchild SemiconductorIn Stock: 13784SA33CA Datasheet

DirectRFQ

BZW06-33B

Diotec SemiconductorIn Stock: 3411BZW06-33B Datasheet

MFR RecommendedRFQ

P6KE39CA

Fairchild SemiconductorIn Stock: 27147P6KE39CA Datasheet

MFR RecommendedRFQ

SA33CA-AP

Micro Commercial CoIn Stock: 839SA33CA-AP Datasheet

MFR RecommendedRFQ

SA33CA-BP

Micro Commercial CoIn Stock: 926SA33CA-BP Datasheet

MFR RecommendedRFQ

SA33CA-TP

Micro Commercial CoIn Stock: 993SA33CA-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SA33C are qualified based on the following critical parameters that determine functional equivalence:

Primary Substitution Criteria:

• Voltage - Reverse Standoff: 33V ± tolerance
• Voltage - Clamping (Max) @ Ipp: within acceptable range (53.3V to 55.97V)
• Current - Peak Pulse (10/1000µs): minimum 9.6A
• Power - Peak Pulse: minimum 500W
• Package / Case: DO-204AC or DO-15 (axial through-hole)
• Type: Zener diode, bidirectional, single channel
• Applications: General Purpose

Substitute parts are grouped into two categories:

Category 1 - Direct Electrical Equivalents (Obsolete Status): SA33CA, SA33CA-BP, SA33CA-TP, and SA33CA-AP maintain identical electrical specifications to the SA33C with minor variations in clamping voltage within acceptable tolerance. These parts are sourced from Micro Commercial Co and Fairchild Semiconductor.

Category 2 - Enhanced Performance Equivalent (Active Status): BZW06-33B from Diotec Semiconductor provides superior specifications with higher peak pulse current (11.1A) and power rating (600W), maintaining the same reverse standoff voltage and compatible package format.

Category 3 - Limited Data Equivalent: P6KE39CA from Fairchild Semiconductor is listed as an active substitute but contains incomplete technical specifications in the provided data.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): SA33CA-BP and SA33CA-TP from Micro Commercial Co are recommended as primary substitutes. Both maintain identical electrical parameters to the SA33C with active product status, ensuring long-term availability. SA33CA-TP is available in Tape & Reel packaging for automated assembly processes, while SA33CA-BP is supplied in bulk format. Both parts are REACH compliant and suitable for general-purpose overvoltage protection applications.

For Enhanced Performance Applications: BZW06-33B from Diotec Semiconductor provides superior specifications with 11.1A peak pulse current and 600W power rating, exceeding the SA33C baseline. This part maintains compatible reverse standoff voltage (33.3V) and package format. The lower minimum operating temperature (-50°C versus -55°C) should be evaluated against application requirements. BZW06-33B is active and available in Cut Tape packaging.

For Legacy System Support: SA33CA from Fairchild Semiconductor is an obsolete equivalent with identical electrical specifications to the SA33C. This part is suitable only when existing inventory must be maintained or when design documentation specifically references this manufacturer variant.

Regarding P6KE39CA: This part is listed as an active substitute but contains insufficient technical data in the provided specifications to establish complete parameter equivalence. Selection of this part requires verification of complete electrical characteristics against application requirements.

Frequently Asked Questions (FAQ)

Q: Can SA33CA-BP be used as a direct replacement for SA33C in existing designs? A: Yes. SA33CA-BP maintains identical electrical specifications including 33V reverse standoff voltage, 53.3V clamping voltage, 9.6A peak pulse current, and 500W power rating. The part is compatible with DO-15 through-hole mounting and operates across the same temperature range (-55°C to 175°C). The primary difference is active product status, ensuring continued availability.

Q: What is the difference between SA33CA-BP and SA33CA-TP? A: Both parts are electrically identical. The difference is packaging format: SA33CA-BP is supplied in bulk, while SA33CA-TP is supplied in Tape & Reel format. Tape & Reel packaging is suitable for automated pick-and-place assembly, while bulk packaging is used for manual assembly or lower-volume applications.

Q: Why does BZW06-33B have higher current and power ratings than SA33C? A: BZW06-33B is a higher-performance variant within the same voltage class. The 11.1A peak pulse current and 600W power rating provide additional margin for transient suppression. This part is suitable for applications requiring enhanced protection or where design margins are critical. The reverse standoff voltage (33.3V) remains compatible with the SA33C specification.

Q: Are all substitute parts RoHS compliant? A: SA33CA-TP and SA33C are explicitly ROHS3 compliant. SA33CA and SA33CA-BP do not specify RoHS status in the provided data. BZW06-33B lists RoHS status as "Not applicable." Compliance verification should be confirmed with the manufacturer or distributor for specific applications requiring RoHS certification.

Q: Can SA33CA-TP be used in applications with operating temperatures below -55°C? A: SA33CA-TP specifies an operating temperature range of -55°C to 175°C (TA), matching the SA33C specification. Both parts are suitable for the same temperature range. BZW06-33B has a minimum operating temperature of -50°C, which is 5°C higher than the SA33C baseline and should be evaluated for applications requiring operation below -50°C.

Q: What is the significance of the DO-204AC and DO-15 package designations? A: DO-204AC and DO-15 are equivalent designations for the same axial through-hole package format. All substitute parts use this identical package, ensuring mechanical and electrical compatibility with existing PCB designs and assembly processes.

Q: Is P6KE39CA a suitable substitute for SA33C? A: P6KE39CA is listed as a manufacturer-recommended substitute but contains incomplete technical specifications in the available data. Complete electrical parameter verification is required before selection for new designs or critical applications.