SA17ARL Equivalent & Substitute Parts

Part Overview

The SA17ARL is a 17V Transient Voltage Suppressor (TVS) diode manufactured by onsemi, rated for 27.6V clamping voltage and 18.1A peak pulse current in an axial through-hole package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The SA17ARL serves general-purpose transient voltage suppression applications requiring unidirectional protection in the 17V standoff range.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	17V
Voltage - Breakdown (Min)	18.9V
Voltage - Clamping (Max) @ Ipp	27.6V
Current - Peak Pulse (10/1000µs)	18.1A
Power - Peak Pulse	500W
Operating Temperature Range	-55°C ~ 150°C (TJ)
Mounting Type	Through Hole
Package / Case	DO-204AC, DO-15, Axial
Type	Zener
Unidirectional Channels	1

Substitute Part Grouping Explanation

Substitution for the SA17ARL is determined by strict electrical and mechanical parameter matching within the TVS diode category. The following criteria establish valid substitutes:

Primary Substitution Criteria:

Voltage - Reverse Standoff: 17V (exact match required)
Voltage - Breakdown (Min): 18.9V minimum
Voltage - Clamping (Max) @ Ipp: 27.6V or lower
Current - Peak Pulse (10/1000µs): minimum 18.1A or higher
Power - Peak Pulse: minimum 500W or higher
Type: Zener diode, unidirectional (1 channel)
Mounting Type: Through Hole
Package Compatibility: DO-204AC, DO-15, or Axial

Substitute parts are grouped into two categories based on electrical performance alignment:

Direct Equivalent (Matched Performance): SA17A meets all primary criteria with equivalent current and power ratings, differing only in clamping voltage (27.7V vs 27.6V) and operating temperature range extension.

Similar Performance (Higher Capability): P5KE17A-AP, P5KE17A-BP, and P5KE17A-TP maintain identical voltage specifications and 500W power rating but with slightly lower peak pulse current (16.1A). SLD17U-017 and SLD17U-017-B exceed all electrical parameters with 184.8A peak pulse current and 5kW power rating, suitable for higher-stress applications.

Limited Performance (Lower Capability): 1N8158 meets voltage specifications but provides only 5.42A peak pulse current and 150W power rating, suitable only for lower-stress transient suppression scenarios.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Operating Temperature	Product Status	Package
SA17ARL	onsemi	17V	18.9V	27.6V	18.1A	500W	-55°C ~ 150°C	Obsolete	DO-204AC, DO-15, Axial
SA17A	Taiwan Semiconductor Corporation	17V	18.9V	27.7V	19A	500W	-55°C ~ 175°C	Active	DO-204AC, DO-15, Axial
1N8158	Microchip Technology	17V	19V	27.7V	5.42A	150W	-55°C ~ 175°C	Active	Axial
P5KE17A-AP	Micro Commercial Co	17V	18.9V	27.6V	16.1A	500W	-65°C ~ 175°C	Active	DO-204AC, DO-15, Axial
P5KE17A-BP	Micro Commercial Co	17V	18.9V	27.6V	16.1A	500W	-65°C ~ 175°C	Active	DO-204AC, DO-15, Axial
P5KE17A-TP	Micro Commercial Co	17V	18.9V	27.6V	16.1A	500W	-65°C ~ 175°C	Active	DO-204AC, DO-15, Axial
SLD17U-017	Littelfuse Inc.	17V	18.9V	27.6V	184.8A	5000W	-55°C ~ 175°C	Active	P600, Axial
SLD17U-017-B	Littelfuse Inc.	17V	18.9V	27.6V	184.8A	5000W	-55°C ~ 175°C	Active	P600, Axial

Engineering Selection Recommendations

Primary Recommendation: SA17A (Taiwan Semiconductor Corporation) is the direct equivalent for SA17ARL replacement. It maintains identical voltage specifications and 500W power rating with marginally higher peak pulse current (19A vs 18.1A). The part is active in production with extended operating temperature range (-55°C ~ 175°C vs -55°C ~ 150°C) and ROHS3 compliance, providing superior long-term availability and regulatory alignment.

Alternative for Extended Temperature Range: P5KE17A-AP, P5KE17A-BP, and P5KE17A-TP (Micro Commercial Co) are functionally equivalent with identical voltage and power specifications. These parts extend the lower operating temperature limit to -65°C and maintain active production status. Peak pulse current is slightly lower at 16.1A, acceptable for applications not requiring the full 18.1A capability.

High-Performance Alternative: SLD17U-017 and SLD17U-017-B (Littelfuse Inc.) exceed all electrical parameters with 184.8A peak pulse current and 5kW power rating. These parts carry AEC-Q101 automotive qualification and ROHS3 compliance. Package format (P600) differs from the original axial configuration, requiring mechanical redesign consideration. Selection is appropriate for applications requiring enhanced transient suppression capability or automotive-grade reliability.

Limited-Capability Alternative: 1N8158 (Microchip Technology) meets voltage specifications but provides only 5.42A peak pulse current and 150W power rating. This part is suitable only for low-stress transient suppression scenarios where the original 18.1A capability is not required.

Frequently Asked Questions (FAQ)

Q: Can SA17A directly replace SA17ARL without circuit modification?

A: Yes. SA17A maintains identical voltage specifications (17V standoff, 18.9V breakdown, 27.6V clamping) and 500W power rating. The 0.1V clamping voltage difference (27.7V vs 27.6V) and higher peak pulse current (19A vs 18.1A) represent improved performance within acceptable tolerance. No circuit redesign is required.

Q: What is the difference between P5KE17A-AP, P5KE17A-BP, and P5KE17A-TP?

A: These three part numbers are electrically identical with the same voltage and power specifications. The suffix designates packaging or tape configuration variants. Selection depends on procurement and assembly requirements rather than electrical performance.

Q: Why do SLD17U-017 and SLD17U-017-B have significantly higher peak pulse current?

A: These parts use the P600 package format, a larger through-hole configuration designed for higher current handling. The 184.8A peak pulse current and 5kW power rating reflect the enhanced thermal and electrical capability of this package. Mechanical board layout changes are required for implementation.

Q: Is 1N8158 suitable as a direct replacement?

A: 1N8158 meets voltage specifications but provides only 5.42A peak pulse current versus the original 18.1A requirement. This part is suitable only for applications where transient energy levels are significantly lower than the original design specification.

Q: What compliance differences exist between substitute parts?

A: SA17A and SLD17U-017/SLD17U-017-B are ROHS3 compliant. The original SA17ARL is RoHS non-compliant. P5KE17A variants and 1N8158 compliance status is not specified in available data. For applications requiring RoHS compliance, SA17A or Littelfuse SLD series are required.

Q: Can package format be changed from axial to P600?

A: SLD17U-017 and SLD17U-017-B use P600 package format instead of standard axial. This requires mechanical redesign of the PCB footprint and component placement. Electrical substitution is valid, but physical implementation requires engineering review.

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