SA33-E3/54 Equivalent & Substitute Parts

Part Overview

The SA33-E3/54 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division, part of the TransZorb® series. This component is designed for general-purpose transient voltage suppression in through-hole applications using the DO-204AC (DO-15) axial package format. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	33V
Voltage - Breakdown (Min)	36.7V
Voltage - Clamping (Max) @ Ipp	59V
Current - Peak Pulse (10/1000µs)	8.5A
Power - Peak Pulse	500W
Operating Temperature	-55°C ~ 175°C (TJ)
Mounting Type	Through Hole
Package / Case	DO-204AC, DO-15, Axial
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the SA33-E3/54 is determined by the following critical parameters:

Reverse standoff voltage within the 33V nominal range
Breakdown voltage minimum at or above 36.7V
Through-hole axial package compatibility (DO-204AC / DO-15)
Unidirectional TVS diode topology
ROHS3 compliance and general-purpose application suitability

Substitute parts must maintain electrical compatibility within these specifications while accommodating variations in clamping voltage, peak pulse current, and power dissipation that remain within acceptable operating margins for the application.

Parameter Comparison

Parameter	SA33-E3/54	SA33A-E3/54	P6KE39A	SA33A	SA33A-TP
Manufacturer	Vishay	Vishay	Taiwan Semiconductor	Fairchild	Micro Commercial Co
Product Status	Obsolete	Active	Active	Obsolete	Active
Voltage - Reverse Standoff (Typ)	33V	33V	33.3V	33V	33V
Voltage - Breakdown (Min)	36.7V	36.7V	37.1V	36.7V	36.7V
Voltage - Clamping (Max) @ Ipp	59V	53.3V	53.9V	53.3V	53.3V
Current - Peak Pulse (10/1000µs)	8.5A	9.4A	11.2A	9.4A	9.6A
Power - Peak Pulse	500W	500W	600W	500W	500W
Package / Case	DO-204AC, DO-15	DO-204AC, DO-15	DO-15	DO-15	DO-15
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For applications currently using the obsolete SA33-E3/54, the following selection criteria apply:

Active Status Priority: SA33A-E3/54, P6KE39A, and SA33A-TP are all active products with current manufacturing support and availability. These are preferred for new designs and ongoing procurement.

Electrical Performance: SA33A-E3/54 and SA33A-TP provide the closest electrical match to the original SA33-E3/54, with identical reverse standoff voltage (33V) and breakdown voltage (36.7V). The clamping voltage is reduced to 53.3V, which represents improved performance characteristics. P6KE39A offers higher peak pulse current (11.2A) and power dissipation (600W), providing additional margin for high-energy transient events.

Compliance and Certification: All substitute parts maintain ROHS3 compliance and are suitable for general-purpose applications. Moisture sensitivity level and REACH status are consistent across all options.

Packaging Considerations: SA33A-E3/54 maintains the full DO-204AC designation. P6KE39A, SA33A, and SA33A-TP are specified as DO-15 package, which is mechanically and electrically compatible with DO-204AC in through-hole applications.

Frequently Asked Questions (FAQ)

Q: Can SA33A-E3/54 be used as a direct replacement for SA33-E3/54?

A: Yes. SA33A-E3/54 is a direct substitute with identical reverse standoff voltage (33V), breakdown voltage (36.7V), and package designation (DO-204AC). The clamping voltage is lower (53.3V vs 59V), which represents improved transient suppression performance. Both parts are ROHS3 compliant and rated for -55°C to 175°C operation.

Q: What is the difference between SA33A-E3/54 and SA33A-TP?

A: Both parts share the same electrical specifications (33V standoff, 36.7V breakdown, 53.3V clamping). SA33A-E3/54 is supplied by Vishay in Cut Tape packaging, while SA33A-TP is supplied by Micro Commercial Co in Cut Tape packaging. Both are active products with equivalent performance.

Q: Why does P6KE39A have higher peak pulse current and power rating?

A: P6KE39A is rated for 11.2A peak pulse current and 600W power dissipation compared to 8.5A and 500W for the SA33-E3/54. This higher rating provides additional margin for transient suppression in applications with higher energy events. The reverse standoff voltage (33.3V) and breakdown voltage (37.1V) remain within the compatible range.

Q: Are DO-15 and DO-204AC packages interchangeable?

A: Yes. DO-15 and DO-204AC are equivalent axial through-hole package designations. Parts specified as DO-15 are mechanically and electrically compatible with DO-204AC footprints in PCB designs.

Q: Should I avoid obsolete parts like SA33A?

A: SA33A is listed as obsolete and should not be selected for new designs or long-term procurement. Active alternatives (SA33A-E3/54, P6KE39A, SA33A-TP) provide equivalent or superior performance with guaranteed manufacturing support and availability.

Q: What compliance certifications apply to all substitute parts?

A: All substitute parts listed are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99. Moisture sensitivity level is 1 (Unlimited) for all parts, indicating no special moisture handling requirements.

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