SA78C Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA78C is a 78V Zener-type transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. Packaged in DO-204AC (DO-15) through-hole configuration, this component provides 132.3V maximum clamping voltage at 4A peak pulse current with 500W peak pulse power handling capability.

The SA78C is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for new production runs, repairs, and system upgrades.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	78V
Voltage - Breakdown (Min)	82.13V
Voltage - Clamping (Max) @ Ipp	132.3V
Current - Peak Pulse (10/1000µs)	4A
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

Substitute Part Grouping Explanation

Substitution eligibility for the SA78C is determined by strict alignment across the following critical parameters:

Voltage - Reverse Standoff (Typ): 78V
Voltage - Breakdown (Min): 82.13V minimum
Voltage - Clamping (Max) @ Ipp: 126V to 132.3V range
Current - Peak Pulse (10/1000µs): 4A to 4.1A range
Power - Peak Pulse: 500W
Operating Temperature Range: -55°C to 175°C minimum
Mounting Type: Through Hole
Package / Case: DO-204AC / DO-15 Axial
Type: Zener
Bidirectional Channels: 1

All substitute parts listed maintain these electrical and mechanical specifications within acceptable tolerances for direct circuit replacement. Substitutes differ only in manufacturer, packaging format (Tape & Reel vs. Bulk), and minor variations in clamping voltage (126V vs. 132.3V) and peak pulse current (4A vs. 4.1A), all within functional equivalence for general-purpose transient suppression applications.

Parameter Comparison

Parameter	SA78C (Littelfuse)	SA78CA (Taiwan Semi)	P5KE78CA-TP (MCC)	SA78CA-AP (MCC)	SA78CA-BP (MCC)	SA78CA-TP (MCC)
Manufacturer	Littelfuse Inc.	Taiwan Semiconductor	Micro Commercial Co	Micro Commercial Co	Micro Commercial Co	Micro Commercial Co
Product Status	Obsolete	Active	Active	Active	Active	Active
Voltage - Reverse Standoff (Typ)	78V	78V	78V	78V	78V	78V
Voltage - Breakdown (Min)	82.13V	86.7V	86.7V	86.7V	86.7V	86.7V
Voltage - Clamping (Max) @ Ipp	132.3V	126V	126V	126V	126V	126V
Current - Peak Pulse (10/1000µs)	4A	4.1A	4A	4A	4A	4A
Power - Peak Pulse	500W	500W	500W	500W	500W	500W
Operating Temperature Range	-55°C ~ 175°C	-55°C ~ 175°C	-65°C ~ 175°C	-55°C ~ 175°C	-55°C ~ 175°C	-55°C ~ 175°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	DO-204AC, DO-15	DO-204AC, DO-15	DO-15	DO-15	DO-15	DO-15
Type	Zener	Zener	Zener	Zener	Zener	Zener
Bidirectional Channels	1	1	1	1	1	1
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging Format	Standard	Tape & Reel (TR)	Bulk	Bulk	Bulk	Bulk
Inventory Status	807 Pcs	691 Pcs	696 Pcs	698 Pcs	847 Pcs	726 Pcs

Engineering Selection Recommendations

All listed substitute parts maintain active product status and ROHS3 compliance, ensuring regulatory alignment and long-term supply chain viability compared to the obsolete SA78C.

SA78CA (Taiwan Semiconductor Corporation) offers the closest electrical match with 4.1A peak pulse current and Tape & Reel packaging, suitable for automated assembly environments.

P5KE78CA-TP (Micro Commercial Co) provides extended operating temperature range (-65°C to 175°C) and is available in bulk packaging, appropriate for applications requiring lower temperature performance.

SA78CA-AP, SA78CA-BP, and SA78CA-TP (all Micro Commercial Co) deliver identical electrical specifications with 4A peak pulse current and bulk packaging. SA78CA-BP offers the highest current inventory (847 Pcs), while SA78CA-TP provides 726 Pcs availability.

All substitute parts are functionally equivalent for general-purpose transient voltage suppression in 78V protection circuits. Selection should prioritize product availability, packaging requirements (Tape & Reel vs. Bulk), and temperature range specifications for the target application.

Frequently Asked Questions (FAQ)

Q: Can SA78CA, P5KE78CA-TP, SA78CA-AP, SA78CA-BP, and SA78CA-TP be used interchangeably with SA78C?

A: Yes. All substitute parts maintain the same reverse standoff voltage (78V), peak pulse power (500W), through-hole mounting configuration, and DO-15 package footprint. Minor variations in clamping voltage (126V vs. 132.3V) and peak pulse current (4A vs. 4.1A) remain within functional tolerance for general-purpose transient suppression applications.

Q: What is the difference between Tape & Reel and Bulk packaging?

A: Tape & Reel packaging (SA78CA) is optimized for automated pick-and-place assembly and high-volume production. Bulk packaging (P5KE78CA-TP, SA78CA-AP, SA78CA-BP, SA78CA-TP) is suitable for manual assembly, repair, and lower-volume applications. Both formats contain identical components; packaging format selection depends on assembly methodology.

Q: Does P5KE78CA-TP offer any advantage over other substitutes?

A: P5KE78CA-TP extends the operating temperature range to -65°C (minimum), compared to -55°C for other substitutes. This specification is relevant only for applications requiring operation below -55°C. For standard temperature range applications (-55°C to 175°C), all substitutes are equivalent.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification, ensuring regulatory alignment with current environmental and hazardous substance restrictions.

Q: Which substitute part has the highest inventory availability?

A: SA78CA-BP (Micro Commercial Co) offers the highest inventory with 847 pieces in stock, followed by SA78CA-TP (726 Pcs) and P5KE78CA-TP (696 Pcs).

Q: Can I mix substitute parts from different manufacturers in the same circuit board?

A: Yes. All substitute parts meet identical electrical specifications for the 78V protection function. Mixing manufacturers and packaging formats within a single design is permissible from an electrical standpoint. However, for manufacturing consistency and traceability, using a single part number per design is recommended.

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