SA45A Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA45A is a 45V working voltage transient voltage suppressor diode in DO-15 axial package configuration, designed for general-purpose overvoltage protection applications. This unidirectional zener-type TVS diode provides 72.7V maximum clamping voltage with 6.9A peak pulse current capability and 500W peak pulse power dissipation.

The original SA45A manufactured by onsemi is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this component specification.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	45	V
Voltage - Breakdown (Min)	50	V
Voltage - Clamping (Max) @ Ipp	72.7	V
Current - Peak Pulse (10/1000µs)	6.9	A
Power - Peak Pulse	500	W
Type	Zener	-
Unidirectional Channels	1	-
Mounting Type	Through Hole	-
Package / Case	DO-204AC, DO-15, Axial	-

Substitute Part Grouping Explanation

Substitute parts for the SA45A TVS diode are classified based on electrical parameter equivalence and package compatibility. The primary substitution criteria are:

Critical Matching Parameters:

Voltage - Reverse Standoff (Typ): 45V
Voltage - Breakdown (Min): 50V
Current - Peak Pulse (10/1000µs): 6.9A minimum
Power - Peak Pulse: 500W
Package / Case: DO-204AC, DO-15, Axial (Through Hole)
Type: Zener, Unidirectional (1 channel)

Direct Equivalents maintain all electrical specifications within the same tolerance band and are pin-compatible replacements.

Similar Parts meet the core voltage and current specifications but may have minor variations in clamping voltage or peak pulse current ratings within acceptable operational ranges, or differ in packaging format (bulk vs. tape & reel).

Parameter Comparison

Part Number	Manufacturer	Status	Standoff Voltage (V)	Breakdown Min (V)	Clamp Voltage (V)	Peak Pulse Current (A)	Package	Packaging Type
SA45A	onsemi	Obsolete	45	50	72.7	6.9	DO-15	Bulk
SA45A-E3/54	Vishay General Semiconductor	Active	45	50	72.7	6.9	DO-204AC (DO-15)	Tape & Reel
SA45AHE3/54	Vishay General Semiconductor	Active	45	50	72.7	6.9	DO-204AC (DO-15)	Tape & Reel
P5KE45A-AP	Micro Commercial Co	Active	45	50	72.7	6.9	DO-15	Bulk
P5KE45A-BP	Micro Commercial Co	Active	45	50	72.7	6.9	DO-15	Bulk
P5KE45A-TP	Micro Commercial Co	Active	45	50	72.7	6.9	DO-15	Bulk
SA45A	Fairchild Semiconductor	Obsolete	45	50	72.7	7.0	DO-204AC (DO-15)	Bulk
SA45A-AP	Micro Commercial Co	Active	45	50	72.7	7.0	DO-15	Bulk
SA45A-BP	Micro Commercial Co	Active	45	50	72.7	7.0	DO-15	Bulk
SA45A-TP	Micro Commercial Co	Active	45	50	72.7	7.0	DO-15	Bulk
SAC45	Littelfuse Inc.	Active	45	50	77.0	6.8	DO-204AC (DO-15)	Cut Tape

Engineering Selection Recommendations

Direct Equivalents (Preferred for Replacement):

SA45A-E3/54 (Vishay General Semiconductor) and SA45AHE3/54 (Vishay General Semiconductor) are direct electrical equivalents with identical voltage and current specifications. Both are active products with ROHS3 compliance. SA45AHE3/54 includes AEC-Q101 automotive qualification, suitable for automotive-grade applications. These parts are available in tape & reel packaging for automated assembly.

Active Alternatives (Electrical Equivalents):

P5KE45A series (Micro Commercial Co) parts—P5KE45A-AP, P5KE45A-BP, and P5KE45A-TP—maintain identical electrical specifications with 6.9A peak pulse current. These are active products available in bulk packaging. Operating temperature range extends to -65°C, providing wider thermal operating margin compared to the original specification.

SA45A variants from Micro Commercial Co (SA45A-AP, SA45A-BP, SA45A-TP) are active products with 7.0A peak pulse current, representing a slight increase in current capability while maintaining all voltage parameters. These provide direct form-factor compatibility in bulk packaging.

Similar Alternative (Minor Parameter Variation):

SAC45 (Littelfuse Inc.) maintains the 45V standoff voltage and 50V minimum breakdown voltage with 6.8A peak pulse current. The clamping voltage is specified at 77V maximum, representing a 4.3V increase compared to the 72.7V specification. This part is active and ROHS3 compliant, available in cut tape packaging. Selection of this part requires confirmation that the higher clamping voltage is acceptable for the application circuit.

Product Status Consideration:

All identified substitutes are active products, eliminating supply chain risk associated with the obsolete onsemi SA45A original part.

Frequently Asked Questions (FAQ)

Q: Can SA45A-E3/54 directly replace the original onsemi SA45A?

A: Yes. SA45A-E3/54 from Vishay General Semiconductor is electrically equivalent with identical voltage standoff (45V), breakdown (50V), clamping (72.7V), and peak pulse current (6.9A) specifications. Both use DO-15 axial package configuration. The primary difference is packaging format: SA45A-E3/54 is supplied in tape & reel format for automated assembly, while the original was bulk packaged.

Q: What is the difference between SA45A-E3/54 and SA45AHE3/54?

A: Both parts are electrically identical with matching voltage and current specifications. SA45AHE3/54 includes AEC-Q101 automotive qualification and is suitable for automotive applications requiring this certification. SA45A-E3/54 is the standard industrial-grade equivalent. Both are active products from Vishay General Semiconductor.

Q: Are the Micro Commercial Co SA45A variants (SA45A-AP, SA45A-BP, SA45A-TP) compatible replacements?

A: Yes, these are compatible replacements. They maintain the 45V standoff voltage, 50V breakdown voltage, and 72.7V clamping voltage. Peak pulse current is specified at 7.0A, which is 0.1A higher than the original 6.9A specification. This represents a slight increase in current capability and is acceptable for applications designed for the original part. The suffix designations (-AP, -BP, -TP) indicate different packaging tape configurations for bulk supply.

Q: How does SAC45 differ from SA45A?

A: SAC45 maintains the same 45V standoff voltage and 50V breakdown voltage. The primary difference is clamping voltage: SAC45 specifies 77V maximum compared to SA45A's 72.7V. Peak pulse current is 6.8A versus 6.9A. The 4.3V higher clamping voltage may affect circuit performance in applications with tight voltage margin requirements. Confirmation of circuit tolerance to higher clamping voltage is necessary before substitution.

Q: What packaging options are available for SA45A substitutes?

A: Substitutes are available in multiple packaging formats: tape & reel (SA45A-E3/54, SA45AHE3/54) for automated assembly lines; bulk packaging (P5KE45A series, SA45A variants from Micro Commercial Co) for manual assembly or lower-volume applications; and cut tape (SAC45) for semi-automated processes. Selection depends on assembly method and production volume requirements.

Q: Are all substitute parts ROHS3 compliant?

A: ROHS3 compliance is confirmed for SA45A-E3/54, SA45AHE3/54, SAC45, and the Fairchild SA45A variant. Compliance status for P5KE45A series and Micro Commercial Co SA45A variants is not specified in the provided data. Verification with the supplier is recommended if ROHS3 compliance is a design requirement.

Q: What is the operating temperature range for substitute parts?

A: Operating temperature ranges vary: Vishay parts (SA45A-E3/54, SA45AHE3/54) and SAC45 specify -55°C to 175°C. Micro Commercial Co parts (P5KE45A series, SA45A variants) specify -65°C to 175°C, providing extended low-temperature operation. The original onsemi SA45A operating temperature is not specified in the provided data.

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