SA33A Transient Voltage Suppressor Equivalent & Substitute Parts

Part Overview

The SA33A is an active Littelfuse Inc. transient voltage suppressor (TVS) diode designed for general-purpose overvoltage protection applications. This unidirectional zener-type TVS operates with a 33V reverse standoff voltage and provides 53.3V maximum clamping voltage at peak pulse current. The component is packaged in DO-204AC (DO-15) axial through-hole configuration and is ROHS3 compliant with unlimited moisture sensitivity rating.

Equivalent and substitute parts are identified when product availability changes, supply chain constraints occur, or design flexibility is required while maintaining electrical and mechanical compatibility within specified parameter tolerances.

Substiute Parts

SA33A

Littelfuse Inc.In Stock: 21284SA33A Datasheet

Current PartRFQ

5KP33A

Diotec SemiconductorIn Stock: 43285KP33A Datasheet

MFR RecommendedRFQ

SA33A-TP

Micro Commercial CoIn Stock: 3421SA33A-TP Datasheet

DirectRFQ

P6KE39A

Taiwan Semiconductor CorporationIn Stock: 18061P6KE39A Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SA33A are qualified based on the following critical parameters that determine functional interchangeability:

Voltage Parameters: Reverse standoff voltage (33V nominal), breakdown voltage minimum (36.7V), and maximum clamping voltage (53.3V) must remain within the specified ranges to ensure proper overvoltage protection without nuisance triggering.

Current and Power Ratings: Peak pulse current and power dissipation capacity must meet or exceed the application requirements. Parts with higher ratings provide additional margin and are acceptable substitutes.

Electrical Type: All substitutes must be unidirectional zener-type TVS diodes with single channel configuration.

Mechanical Compatibility: Through-hole mounting and DO-15 axial package configuration are required for direct board-level substitution without layout modification.

Compliance and Environmental: ROHS3 compliance and operating temperature range (-55°C to 175°C) ensure regulatory and thermal compatibility.

Parameter Comparison

Engineering Selection Recommendations

SA33A-TP (Micro Commercial Co): Direct equivalent with identical electrical specifications (33V standoff, 53.3V clamp, 9.6A peak pulse, 500W power). ROHS3 compliant with matching operating temperature range (-55°C to 175°C). Supplier device package is DO-15, compatible with SA33A DO-204AC footprint. This part provides pin-for-pin substitution with no design modification required.

P6KE39A (Taiwan Semiconductor Corporation): Functionally compatible substitute with marginally higher voltage parameters (33.3V standoff, 37.1V breakdown, 53.9V clamp) and increased current/power ratings (11.2A peak pulse, 600W power). ROHS3 compliant. Operating temperature range not specified in provided data. Suitable for applications where higher transient energy absorption is beneficial.

5KP33A (Diotec Semiconductor): High-power substitute with identical voltage specifications (33V standoff, 36.7V breakdown, 53.3V clamp) but significantly elevated current and power ratings (94A peak pulse, 5000W power). Package configuration is P600 axial, mechanically compatible with through-hole mounting. RoHS status not applicable; REACH status vendor undefined. Appropriate for high-energy transient protection applications where standard power ratings are insufficient.

Frequently Asked Questions (FAQ)

Q: Can SA33A-TP replace SA33A directly without circuit modification?

A: Yes. SA33A-TP is a direct equivalent with identical voltage standoff (33V), breakdown voltage (36.7V), clamping voltage (53.3V), peak pulse current (9.6A), and power rating (500W). Both are ROHS3 compliant with matching operating temperature ranges. No circuit or layout changes are required.

Q: What is the primary difference between SA33A and P6KE39A?

A: P6KE39A has marginally higher voltage parameters (33.3V standoff vs. 33V, 53.9V clamp vs. 53.3V) and increased current/power capacity (11.2A and 600W vs. 9.6A and 500W). Both maintain unidirectional zener-type operation in DO-15 packages. P6KE39A is suitable when additional transient energy margin is required.

Q: Is 5KP33A compatible with SA33A in the same circuit?

A: 5KP33A maintains identical voltage specifications (33V standoff, 36.7V breakdown, 53.3V clamp) and unidirectional zener operation, making it electrically compatible. However, the P600 package differs from DO-204AC. Both are axial through-hole configurations and mechanically compatible on standard PCB layouts. The 5KP33A's significantly higher power rating (5000W vs. 500W) makes it suitable for high-energy transient environments.

Q: What compliance certifications are critical for substitution?

A: ROHS3 compliance is specified for SA33A, SA33A-TP, and P6KE39A. The 5KP33A RoHS status is not applicable per provided data. For applications requiring ROHS3 compliance, SA33A-TP and P6KE39A are preferred. REACH status is unaffected for SA33A, SA33A-TP, and P6KE39A; 5KP33A REACH status is vendor undefined.

Q: Are operating temperature ranges equivalent across all substitutes?

A: SA33A and SA33A-TP both specify -55°C to 175°C operating range. 5KP33A specifies -50°C to 175°C (1°C higher minimum). P6KE39A operating temperature is not specified in provided data. For applications requiring full -55°C minimum operation, SA33A or SA33A-TP are specified choices.

Q: Can these parts be used interchangeably in high-frequency transient protection circuits?

A: All substitutes are unidirectional zener-type TVS diodes with identical channel configuration (1 channel). Capacitance data is not provided for any part. Substitution is based on voltage clamping and current/power specifications. Frequency-dependent performance characteristics require detailed datasheet review beyond provided parameters.