SA28C Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA28C is a 28V Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in through-hole applications. This part is classified as obsolete, making equivalent substitute parts necessary for ongoing design support and procurement. The SA28C operates with a 28V reverse standoff voltage, 47.67V maximum clamping voltage, and 11.2A peak pulse current in a DO-204AC (DO-15) axial package. Substitute parts must maintain electrical compatibility across voltage ratings, current handling, and thermal specifications while supporting the same through-hole mounting configuration.

Key Parameters

Parameter	SA28C (Littelfuse)
Voltage - Reverse Standoff (Typ)	28V
Voltage - Breakdown (Min)	29.48V
Voltage - Clamping (Max) @ Ipp	47.67V
Current - Peak Pulse (10/1000µs)	11.2A
Power - Peak Pulse	500W
Operating Temperature Range	-55°C ~ 175°C (TJ)
Mounting Type	Through Hole
Package / Case	DO-204AC (DO-15), Axial
Type	Zener
Bidirectional Channels	1
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the SA28C are qualified based on the following electrical and mechanical parameters:

Critical Matching Parameters:

Reverse Standoff Voltage: 28V (±tolerance)
Package / Case: DO-204AC (DO-15) axial through-hole configuration
Bidirectional Channels: 1
Type: Zener TVS diode
Applications: General Purpose

Allowable Variation Parameters:

Voltage - Breakdown (Min): Range 29.48V to 31.4V
Voltage - Clamping (Max) @ Ipp: Range 45.4V to 59V
Current - Peak Pulse (10/1000µs): Range 11.2A to 13.8A
Power - Peak Pulse: 500W to 600W
Operating Temperature Range: -55°C to -50°C (minimum), up to 175°C (maximum)

Substitute parts must maintain the same reverse standoff voltage class and through-hole axial package to ensure direct mechanical and electrical compatibility in existing circuit designs.

Parameter Comparison

Parameter	SA28C (Littelfuse)	SA28CA (Taiwan Semiconductor)	BZW06-28B (Diotec)	P6KE33CA (Diotec)	SA28CA-AP (MCC)	SA28CA-BP (MCC)	SA28CA-TP (MCC)
Voltage - Reverse Standoff (Typ)	28V	28V	28.2V	28.2V	28V	28V	28V
Voltage - Breakdown (Min)	29.48V	31.1V	31.4V	31.4V	31.1V	31.1V	31.1V
Voltage - Clamping (Max) @ Ipp	47.67V	59V	45.7V	45.7V	45.4V	45.4V	45.4V
Current - Peak Pulse (10/1000µs)	11.2A	11.5A	13.1A	13.8A	11.2A	11.2A	11.2A
Power - Peak Pulse	500W	500W	600W	600W	500W	500W	500W
Operating Temperature Range	-55°C ~ 175°C	-55°C ~ 175°C	-50°C ~ 175°C	-50°C ~ 175°C	-55°C ~ 175°C	-55°C ~ 175°C	-55°C ~ 175°C
Package / Case	DO-204AC (DO-15)	DO-204AC (DO-15)	DO-204AC (DO-15)	DO-204AC (DO-15)	DO-204AC (DO-15)	DO-204AC (DO-15)	DO-204AC (DO-15)
Type	Zener	Zener	Zener	Zener	Zener	Zener	Zener
Bidirectional Channels	1	1	1	1	1	1	1
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

All substitute parts listed maintain ROHS3 compliance and are classified as active products, ensuring long-term availability and supply chain continuity compared to the obsolete SA28C.

SA28CA (Taiwan Semiconductor Corporation): Direct functional equivalent with identical reverse standoff voltage (28V) and operating temperature range (-55°C ~ 175°C). Clamping voltage of 59V is higher than the original 47.67V, suitable for applications requiring additional overvoltage margin. Active product status with 1289 units in stock.

BZW06-28B (Diotec Semiconductor): Meets reverse standoff voltage specification (28.2V) with enhanced current handling (13.1A vs. 11.2A) and increased power dissipation (600W vs. 500W). Clamping voltage of 45.7V is lower than the original, providing tighter voltage regulation. Operating temperature minimum of -50°C (vs. -55°C) is acceptable for most general-purpose applications. High inventory availability (88,984 units).

P6KE33CA (Diotec Semiconductor): Functionally equivalent with 28.2V reverse standoff voltage and 45.7V clamping voltage. Peak pulse current of 13.8A and 600W power dissipation exceed original specifications. Operating temperature range of -50°C ~ 175°C is suitable for general-purpose protection circuits. 9,278 units in stock.

SA28CA-AP, SA28CA-BP, SA28CA-TP (Micro Commercial Co): All three variants share identical electrical specifications with 28V reverse standoff voltage, 31.1V breakdown voltage, and 45.4V clamping voltage. Peak pulse current and power dissipation match the original SA28C (11.2A, 500W). Operating temperature range of -55°C ~ 175°C is identical to the original. These parts differ only in packaging configuration (Bulk) and are available in quantities of 817, 1,081, and 883 units respectively.

Frequently Asked Questions (FAQ)

Q: Can I directly replace SA28C with any of these substitute parts?

A: Yes, all listed substitute parts are electrically and mechanically compatible with the SA28C in DO-204AC (DO-15) through-hole applications. All maintain the 28V reverse standoff voltage class and single bidirectional channel configuration required for direct substitution.

Q: What is the difference between the SA28CA variants (SA28CA-AP, SA28CA-BP, SA28CA-TP)?

A: These three Micro Commercial Co parts are electrically identical with matching voltage and current specifications. The designations (-AP, -BP, -TP) indicate different packaging or tape configurations (Bulk packaging). Selection between variants depends on procurement and assembly requirements rather than electrical performance.

Q: Why does SA28CA have a higher clamping voltage (59V) than the original SA28C (47.67V)?

A: The SA28CA maintains the same 28V reverse standoff voltage but exhibits different clamping characteristics. The higher clamping voltage provides additional overvoltage margin in the circuit. This is acceptable for general-purpose protection applications where the critical parameter is the reverse standoff voltage, not the exact clamping voltage.

Q: Are BZW06-28B and P6KE33CA suitable replacements if my circuit requires the lowest possible clamping voltage?

A: Both Diotec parts offer 45.7V clamping voltage, which is lower than the original SA28C (47.67V) and the SA28CA (59V). These parts are suitable for applications where tighter voltage regulation is beneficial. However, verify that your circuit design can accommodate the lower clamping threshold.

Q: What is the significance of the operating temperature range difference between -55°C and -50°C?

A: The SA28C, SA28CA, and Micro Commercial Co variants support -55°C minimum operating temperature, while Diotec parts (BZW06-28B, P6KE33CA) support -50°C minimum. For applications operating below -50°C, select SA28CA or the Micro Commercial Co variants. For standard industrial applications (-40°C to +85°C ambient), all parts are suitable.

Q: Which substitute part has the highest current handling capability?

A: P6KE33CA offers the highest peak pulse current at 13.8A, followed by BZW06-28B at 13.1A. Both Diotec parts also provide 600W power dissipation compared to 500W in the original and most substitutes. These enhanced ratings provide additional design margin for high-energy transient protection.

Q: Are all substitute parts RoHS3 compliant?

A: Yes, all substitute parts listed are ROHS3 compliant, meeting environmental and regulatory requirements for modern electronics manufacturing and assembly.

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