SA43 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA43 is a unidirectional Zener-type transient voltage suppressor diode manufactured by Littelfuse, designed for general-purpose overvoltage protection applications. The device features a 43V reverse standoff voltage with a 72.87V maximum clamping voltage and 7.3A peak pulse current capability in a through-hole DO-204AC (DO-15) axial package. The SA43 is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Multiple active alternatives from Micro Commercial Co and Fairchild Semiconductor provide functional equivalence with comparable electrical characteristics.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	43	V
Voltage - Breakdown (Min)	45.27	V
Voltage - Clamping (Max) @ Ipp	72.87	V
Current - Peak Pulse (10/1000µs)	7.3	A
Power - Peak Pulse	500	W
Operating Temperature Range	-55 to 175	°C (TJ)
Package / Case	DO-204AC, DO-15, Axial	—
Mounting Type	Through Hole	—
Type	Zener	—
Unidirectional Channels	1	—

Substitute Part Grouping Explanation

Substitution of the SA43 is determined by strict equivalence across the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 43V
Voltage - Clamping (Max) @ Ipp: 69.4V to 72.87V range
Current - Peak Pulse (10/1000µs): 7.2A to 7.3A range
Power - Peak Pulse: 500W
Package / Case: DO-204AC, DO-15, Axial
Mounting Type: Through Hole
Type: Zener, Unidirectional

All substitute parts listed maintain these core electrical specifications within acceptable engineering tolerances. The SA43A variant from Fairchild Semiconductor and the SA43A and P5KE43A variants from Micro Commercial Co satisfy these substitution criteria. Differences in clamping voltage (69.4V vs. 72.87V) and peak pulse current (7.2A vs. 7.3A) fall within standard component tolerance ranges for this device category.

Parameter Comparison

Parameter	SA43 (Littelfuse)	SA43A (Fairchild)	SA43A-AP (MCC)	SA43A-BP (MCC)	SA43A-TP (MCC)	P5KE43A-AP (MCC)	P5KE43A-BP (MCC)	P5KE43A-TP (MCC)
Voltage - Reverse Standoff (Typ)	43V	43V	43V	43V	43V	43V	43V	43V
Voltage - Breakdown (Min)	45.27V	47.8V	47.8V	47.8V	47.8V	47.8V	47.8V	47.8V
Voltage - Clamping (Max) @ Ipp	72.87V	69.4V	69.4V	69.4V	69.4V	69.4V	69.4V	69.4V
Current - Peak Pulse (10/1000µs)	7.3A	7.3A	7.3A	7.3A	7.3A	7.2A	7.2A	7.2A
Power - Peak Pulse	500W	500W	500W	500W	500W	500W	500W	500W
Operating Temperature Range	-55 to 175°C	-55 to 175°C	-55 to 175°C	-55 to 175°C	-55 to 175°C	-65 to 175°C	-65 to 175°C	-65 to 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	DO-204AC, DO-15
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Type	Zener	Zener	Zener	Zener	Zener	Zener	Zener	Zener
Product Status	Obsolete	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

For new designs and production transitions from the obsolete SA43, the Micro Commercial Co SA43A and P5KE43A series parts are recommended based on active product status and current availability. The SA43A-AP, SA43A-BP, and SA43A-TP variants maintain identical peak pulse current (7.3A) and operating temperature range (-55 to 175°C) as the original SA43, providing direct functional equivalence. The P5KE43A-AP, P5KE43A-BP, and P5KE43A-TP variants offer extended low-temperature operation (-65°C minimum) with marginally reduced peak pulse current (7.2A), suitable for applications requiring enhanced cold-temperature performance.

The Fairchild Semiconductor SA43A provides an alternative with matching electrical specifications and obsolete status classification. All substitute parts maintain ROHS3 compliance or REACH unaffected status, ensuring regulatory compatibility with existing design requirements.

Frequently Asked Questions (FAQ)

Q: Can the SA43A from Fairchild Semiconductor directly replace the Littelfuse SA43?

A: Yes. The SA43A maintains identical reverse standoff voltage (43V), peak pulse current (7.3A), power rating (500W), operating temperature range (-55 to 175°C), and DO-204AC through-hole package configuration. The clamping voltage difference (69.4V vs. 72.87V) falls within standard component tolerance ranges for this device category.

Q: What is the difference between the SA43A and P5KE43A variants from Micro Commercial Co?

A: Both series maintain the 43V reverse standoff voltage and 500W power rating. The SA43A provides 7.3A peak pulse current with -55 to 175°C operating range. The P5KE43A provides 7.2A peak pulse current with an extended -65 to 175°C operating range. Selection depends on whether the application requires the higher peak pulse current or extended low-temperature capability.

Q: Are all substitute parts available in the same DO-204AC axial package?

A: Yes. All listed substitute parts are manufactured in the DO-204AC (DO-15) axial through-hole package, ensuring mechanical and electrical compatibility with existing PCB layouts and assembly processes.

Q: What is the significance of the -AP, -BP, and -TP suffixes on Micro Commercial Co parts?

A: These suffixes denote packaging and tape configuration variants. All three variants maintain identical electrical specifications and are functionally equivalent for circuit design purposes. Selection is based on procurement and assembly requirements.

Q: Why is the SA43 classified as obsolete?

A: The SA43 from Littelfuse has reached end-of-life status. Active alternatives from Micro Commercial Co ensure continued availability and supply chain continuity for applications requiring 43V TVS diode protection.

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