SA28A Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA28A is a unidirectional Zener-type transient voltage suppressor diode manufactured by onsemi, designed for general-purpose overvoltage protection in through-hole axial configurations. The device features a 28V reverse standoff voltage with a 45.4V maximum clamping voltage at 11A peak pulse current and 500W peak pulse power dissipation. The main part is classified as obsolete, necessitating identification of active equivalent and substitute components for ongoing design requirements and procurement continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	28V	V
Voltage - Breakdown (Min)	31.1V	V
Voltage - Clamping (Max) @ Ipp	45.4V	V
Current - Peak Pulse (10/1000µs)	11A	A
Power - Peak Pulse	500W	W
Operating Temperature Range	-55°C to 150°C (TJ)	°C
Mounting Type	Through Hole	—
Package / Case	DO-204AC, DO-15, Axial	—
Type	Zener	—
Unidirectional Channels	1	—

Substitute Part Grouping Explanation

Substitution eligibility for the SA28A is determined by the following critical parameters:

Voltage Rating Alignment: Reverse standoff voltage of 28V ±tolerance and breakdown voltage minimum of 31.1V
Clamping Voltage: Maximum clamping voltage at rated peak pulse current must not exceed 45.4V to maintain circuit protection integrity
Peak Pulse Current: Minimum 11A at 10/1000µs pulse profile to handle transient events
Power Dissipation: Minimum 500W peak pulse power rating
Package Compatibility: Through-hole axial or DO-204AC (DO-15) configurations for direct PCB mounting replacement
Temperature Range: Operating temperature capability of -55°C to 150°C minimum

Parts are classified into two categories:

Direct Substitutes maintain electrical specifications within the SA28A envelope and support identical circuit functionality with no design modification required.

Similar Substitutes share the core voltage rating and general-purpose application but may exhibit variations in peak pulse current, clamping voltage, power dissipation, or package form factor. Selection requires circuit-level evaluation of transient energy absorption requirements.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Operating Temperature	Package / Case	Product Status	RoHS Status
SA28A	onsemi	28V	31.1V	45.4V	11A	500W	-55°C ~ 150°C	DO-204AC, DO-15, Axial	Obsolete	RoHS non-compliant
SA28A	Fairchild Semiconductor	28V	31.1V	45.4V	11.2A	500W	-55°C ~ 175°C	DO-204AC, DO-15, Axial	Obsolete	ROHS3 Compliant
SA28A-E3/54	Vishay General Semiconductor - Diodes Division	28V	31.1V	45.4V	11A	500W	-55°C ~ 175°C	DO-204AC, DO-15, Axial	Active	ROHS3 Compliant
SA28AHE3/54	Vishay General Semiconductor - Diodes Division	28V	31.1V	45.4V	11A	500W	-55°C ~ 175°C	DO-204AC, DO-15, Axial	Active	ROHS3 Compliant
SA28A-B	Littelfuse Inc.	28V	31.1V	45.4V	11.2A	500W	-55°C ~ 175°C	DO-204AC, DO-15, Axial	Active	ROHS3 Compliant
LCE28A	Littelfuse Inc.	28V	31.1V	45.5V	33A	1500W	-55°C ~ 175°C	DO-201AA, DO-27, Axial	Active	ROHS3 Compliant
1N8163	Microchip Technology	28V	31.4V	45.7V	3.28A	150W	-55°C ~ 175°C	Axial	Active	RoHS non-compliant
BZW06-28	Taiwan Semiconductor Corporation	28.2V	31.4V	59V	68A (8/20µs)	600W	-55°C ~ 175°C	DO-204AC, DO-15, Axial	Active	ROHS3 Compliant
LCE24A	Littelfuse Inc.	24V	26.7V	38.9V	39A	1500W	-55°C ~ 175°C	DO-201AA, DO-27, Axial	Active	ROHS3 Compliant
LCE26A	Littelfuse	26V	28.9V	42.1V	36A	1500W	-55°C ~ 175°C	DO-201AA, DO-27, Axial	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Substitutes (No Design Modification Required)

SA28A-E3/54 and SA28AHE3/54 (Vishay TransZorb® series) are the primary direct substitutes. Both maintain identical electrical specifications to the original SA28A with 28V reverse standoff, 31.1V minimum breakdown, and 45.4V maximum clamping voltage. SA28A-E3/54 is available in active product status with ROHS3 compliance in cut tape packaging. SA28AHE3/54 offers automotive-grade qualification (AEC-Q101) in tape and reel packaging, suitable for high-reliability applications requiring extended temperature operation to 175°C.

SA28A-B (Littelfuse SA series) provides direct electrical equivalence with 11.2A peak pulse current and ROHS3 compliance in active product status. This variant supports bulk packaging and extends operating temperature to 175°C.

The Fairchild Semiconductor SA28A variant maintains identical electrical specifications but carries obsolete product status, limiting procurement viability despite ROHS3 compliance.

Similar Substitutes (Circuit-Level Evaluation Required)

LCE28A (Littelfuse LCE series) matches the 28V voltage rating and 45.5V clamping voltage but provides significantly higher peak pulse current (33A) and power dissipation (1500W) in a DO-201 package. This component is suitable for applications requiring enhanced transient energy absorption beyond the SA28A baseline.

BZW06-28 (Taiwan Semiconductor Corporation) maintains the 28.2V reverse standoff voltage but exhibits higher clamping voltage (59V) and substantially higher peak pulse current (68A at 8/20µs pulse profile) with 600W power dissipation. The elevated clamping voltage may exceed circuit protection thresholds in sensitive applications.

1N8163 (Microchip Technology) shares the 28V voltage rating but provides only 3.28A peak pulse current and 150W power dissipation, making it unsuitable for high-energy transient events. This component is limited to low-current protection applications.

LCE24A and LCE26A represent voltage-shifted alternatives with 24V and 26V reverse standoff ratings respectively. These are not direct substitutes and require circuit redesign validation.

Compliance and Availability Considerations

For new designs requiring RoHS compliance, SA28A-E3/54, SA28AHE3/54, SA28A-B, LCE28A, BZW06-28, LCE24A, and LCE26A all meet ROHS3 requirements. The original SA28A and 1N8163 are RoHS non-compliant.

SA28AHE3/54 is the recommended primary substitute for automotive and high-reliability applications due to AEC-Q101 qualification and active product status. SA28A-E3/54 is the recommended primary substitute for general industrial applications with active product status and standard commercial qualification.

Frequently Asked Questions (FAQ)

Q: Can SA28A-E3/54 be used as a direct replacement for the obsolete SA28A?

A: Yes. SA28A-E3/54 maintains identical electrical specifications: 28V reverse standoff, 31.1V minimum breakdown, 45.4V maximum clamping voltage, and 11A peak pulse current. Both use DO-204AC (DO-15) axial packaging. The primary difference is product status (active vs. obsolete) and extended operating temperature range (-55°C to 175°C vs. -55°C to 150°C). No circuit modification is required.

Q: What is the difference between SA28A-E3/54 and SA28AHE3/54?

A: Both parts are electrically identical with matching voltage and current ratings. SA28AHE3/54 includes automotive-grade qualification (AEC-Q101) and is supplied in tape and reel packaging, making it suitable for high-volume automotive and mission-critical applications. SA28A-E3/54 is supplied in cut tape packaging for standard industrial use. Selection depends on application requirements and packaging format.

Q: Why is LCE28A listed as a similar substitute rather than a direct substitute?

A: LCE28A matches the 28V voltage rating and 45.5V clamping voltage but uses a different package (DO-201 vs. DO-204AC) and provides significantly higher peak pulse current (33A vs. 11A) and power dissipation (1500W vs. 500W). While electrically compatible for the voltage protection function, the higher current rating and different package form factor require PCB layout evaluation and may not fit existing through-hole positions designed for DO-204AC components.

Q: Can BZW06-28 replace SA28A in all applications?

A: BZW06-28 is not a direct substitute. While it maintains a similar 28.2V reverse standoff voltage, it exhibits significantly higher clamping voltage (59V vs. 45.4V) and peak pulse current (68A vs. 11A). The elevated clamping voltage may exceed protection thresholds in sensitive circuits. Use BZW06-28 only when higher transient energy absorption is required and circuit voltage limits permit the higher clamping voltage.

Q: Is 1N8163 a suitable replacement for SA28A?

A: 1N8163 is not recommended as a replacement. Although it shares the 28V reverse standoff voltage, it provides only 3.28A peak pulse current and 150W power dissipation compared to SA28A's 11A and 500W. This component is limited to low-current protection applications and cannot handle the transient energy levels for which SA28A is designed.

Q: What packaging considerations apply when selecting a substitute?

A: The original SA28A uses DO-204AC (DO-15) axial through-hole packaging. Direct substitutes SA28A-E3/54, SA28AHE3/54, and SA28A-B maintain this package format for direct PCB mounting. LCE28A uses DO-201 packaging, which has different lead spacing and may not fit existing PCB holes without layout modification. Verify package dimensions and lead pitch before selecting a substitute with different packaging.

Q: Are all substitute parts RoHS compliant?

A: No. The original SA28A and 1N8163 are RoHS non-compliant. SA28A-E3/54, SA28AHE3/54, SA28A-B, LCE28A, BZW06-28, LCE24A, and LCE26A all meet ROHS3 compliance requirements. For applications requiring RoHS compliance, select from the ROHS3-compliant alternatives.

Q: What is the temperature operating range difference between SA28A and its substitutes?

A: The original SA28A operates from -55°C to 150°C. All active substitutes (SA28A-E3/54, SA28AHE3/54, SA28A-B, LCE28A, BZW06-28, LCE24A, LCE26A, and 1N8163) extend the upper temperature limit to 175°C, providing improved thermal margin for high-temperature environments.

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