SMA6L33A Equivalent & Substitute Parts

Part Overview

The SMA6L33A is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose transient voltage protection applications. This surface-mount component operates across a temperature range of -65°C to 150°C and is RoHS3 compliant. The part is currently active in production with 726 units in stock.

Equivalent and substitute parts are identified when they maintain the same reverse standoff voltage (33V), breakdown voltage (36.7V minimum), and core electrical performance characteristics while potentially offering different clamping voltages, peak pulse currents, or package configurations suited to specific application requirements.

Substiute Parts

SMA6L33A

Littelfuse Inc.In Stock: 750SMA6L33A Datasheet

Current PartRFQ

TPSMA6L33A

Littelfuse Inc.In Stock: 6427TPSMA6L33A Datasheet

DirectRFQ

SM4T39AY

STMicroelectronicsIn Stock: 4543SM4T39AY Datasheet

MFR RecommendedRFQ

SMA6J33A-TR

STMicroelectronicsIn Stock: 5456SMA6J33A-TR Datasheet

MFR RecommendedRFQ

SMAJ33A-TR

STMicroelectronicsIn Stock: 20378SMAJ33A-TR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SMA6L33A is determined by the following critical parameters:

Primary Matching Criteria:

• Voltage - Reverse Standoff (Typ): 33V
• Voltage - Breakdown (Min): 36.7V
• Unidirectional Channels: 1
• Type: Zener
• RoHS3 Compliance
• Surface Mount configuration

Secondary Variation Parameters (allowable differences):

• Voltage - Clamping (Max) @ Ipp: 53.3V to 69.7V
• Current - Peak Pulse: 11.3A to 57A
• Power - Peak Pulse: 400W to 600W
• Package / Case: DO-221AC or DO-214AC (both SMA form factors)
• Operating Temperature range: -65°C to -50°C minimum; 150°C to 175°C maximum
• Manufacturer: Littelfuse Inc. or STMicroelectronics

Parts meeting all primary criteria are classified as direct substitutes. Variations in clamping voltage, peak pulse current, and package form factor are acceptable when the application circuit design accommodates the different electrical performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

TPSMA6L33A (Littelfuse Inc.) is the closest direct substitute for SMA6L33A. Both parts share identical electrical specifications (33V standoff, 36.7V breakdown, 53.3V clamping, 11.3A peak pulse, 600W power rating) and the same DO-221AC package. TPSMA6L33A carries automotive-grade qualification (AEC-Q101) and operates across -50°C to 150°C, compared to the standard-grade SMA6L33A operating range of -65°C to 150°C. This part is suitable for applications where automotive-grade reliability is required or preferred, with 6400 units in stock.

SMA6J33A-TR (STMicroelectronics) maintains the 33V standoff and 36.7V breakdown specifications but increases clamping voltage to 60.8V and peak pulse current to 57A (8/20µs). The package transitions to DO-214AC (SMA form factor). Operating temperature extends to 175°C maximum. This substitute is appropriate for applications requiring higher transient current handling capacity. 5400 units in stock.

SMAJ33A-TR (STMicroelectronics) also maintains 33V standoff and 36.7V breakdown but provides 69.7V clamping and 33A peak pulse current (8/20µs) in DO-214AC package. Operating temperature range is -55°C to 150°C. This part offers higher clamping voltage performance with 20268 units in stock, the highest inventory availability among substitutes.

SM4T39AY (STMicroelectronics) shares the same 33V standoff and 36.7V breakdown specifications with 69.7V clamping and 33A peak pulse current (8/20µs). It carries automotive-grade qualification (AEC-Q101) and operates across -55°C to 150°C in DO-214AC package. 4485 units in stock.

All substitute parts are RoHS3 compliant, active in production, and suitable for general-purpose transient voltage suppression applications. Selection between substitutes depends on specific application requirements for clamping voltage, peak pulse current capacity, operating temperature range, and package compatibility with existing PCB layouts.

Frequently Asked Questions (FAQ)

Q: Can TPSMA6L33A replace SMA6L33A in all applications?

A: Yes, TPSMA6L33A is a direct electrical equivalent with identical voltage and current specifications. The primary difference is automotive-grade qualification (AEC-Q101) and a slightly narrower minimum operating temperature (-50°C vs. -65°C). If your application operates above -50°C, this substitute is fully compatible. Both use the same DO-221AC package.

Q: What is the difference between DO-221AC and DO-214AC packages?

A: Both are surface-mount SMA form factors with identical electrical performance. DO-221AC (used by SMA6L33A and TPSMA6L33A) and DO-214AC (used by SMA6J33A-TR, SMAJ33A-TR, and SM4T39AY) have different physical dimensions and lead configurations. PCB layout and footprint compatibility must be verified before substitution.

Q: Why do some substitutes have higher clamping voltages (60.8V or 69.7V) compared to the original 53.3V?

A: Higher clamping voltage indicates the diode conducts at a higher voltage threshold during transient events. This affects circuit protection characteristics. Selection depends on the specific voltage protection requirement of your application. Higher clamping voltage substitutes are suitable when the application circuit design accommodates this parameter difference.

Q: Are all substitute parts RoHS3 compliant?

A: Yes, all listed substitute parts (TPSMA6L33A, SM4T39AY, SMA6J33A-TR, and SMAJ33A-TR) are RoHS3 compliant, matching the compliance status of the original SMA6L33A.

Q: What does AEC-Q101 qualification mean?

A: AEC-Q101 is an automotive-grade qualification standard. TPSMA6L33A, SM4T39AY, and SMAJ33A-TR carry this certification, indicating they meet automotive industry reliability and performance requirements. This qualification is optional for general-purpose applications but required for automotive use cases.

Q: Can I use SMA6J33A-TR or SMAJ33A-TR if my application requires higher transient current handling?

A: Yes. SMA6J33A-TR provides 57A peak pulse current (vs. 11.3A in the original), and SMAJ33A-TR provides 33A peak pulse current. Both are suitable for applications requiring higher transient current capacity. Verify that your circuit design accommodates the different clamping voltages (60.8V and 69.7V respectively).

Q: Which substitute has the best inventory availability?

A: SMAJ33A-TR has the highest inventory with 20268 units in stock, followed by SMA6J33A-TR (5400 units), TPSMA6L33A (6400 units), and SM4T39AY (4485 units).

Q: What is the operating temperature range difference between substitutes?

A: SMA6L33A operates -65°C to 150°C. TPSMA6L33A operates -50°C to 150°C. SMA6J33A-TR extends to 175°C maximum. SM4T39AY and SMAJ33A-TR operate -55°C to 150°C. Select based on your application's thermal requirements.