5KP8.5A-E3/51 Equivalent & Substitute Parts

Part Overview

The 5KP8.5A-E3/51 is a unidirectional transient voltage suppressor (TVS) diode from Vishay General Semiconductor - Diodes Division, designed for general-purpose overvoltage protection in through-hole applications. This part operates with an 8.5V reverse standoff voltage and provides 14.4V maximum clamping voltage at peak pulse current. The 5KP8.5A-E3/51 is classified as obsolete. Equivalent and substitute parts are available from multiple manufacturers in active production status, offering identical or compatible electrical characteristics with modern availability and compliance certifications.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	8.5	V
Voltage - Breakdown (Min)	9.44	V
Voltage - Clamping (Max) @ Ipp	14.4	V
Current - Peak Pulse (10/1000µs)	347	A
Power - Peak Pulse	5000	W
Operating Temperature Range	-55 to 175	°C
Mounting Type	Through Hole	—
Package / Case	P600, Axial	—
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution for the 5KP8.5A-E3/51 is determined by strict equivalence of the following electrical and mechanical parameters:

Voltage - Reverse Standoff: 8.5V (typ)
Voltage - Breakdown: 9.44V (min)
Voltage - Clamping: 14.4V (max) @ Ipp
Current - Peak Pulse: 347A nominal (10/1000µs)
Power - Peak Pulse: 5000W
Operating Temperature: -55°C to 175°C
Mounting Type: Through Hole
Package / Case: P600, Axial (primary) or R-6, Axial (compatible)
Type: Zener, Unidirectional

Substitute parts are grouped into two categories:

Category A: Direct Electrical & Package Equivalents (P600 Package) Parts maintaining identical voltage ratings, clamping characteristics, and P600 axial package configuration.

Category B: Compatible Alternatives (Different Package or Slightly Variant Peak Current) Parts with equivalent voltage performance but alternative package types (R-6) or minor peak current variations within acceptable tolerance ranges.

Parameter Comparison

Part Number	Manufacturer	Vr Standoff (V)	V Breakdown Min (V)	V Clamp Max @ Ipp (V)	Ipp (A)	Power Peak (W)	Package	Status
5KP8.5A-E3/51	Vishay	8.5	9.44	14.4	347	5000	P600	Obsolete
5KP8.5AHE3/54	Vishay	8.5	9.44	14.4	347	5000	P600	Active
5KP8.5A-E3/54	Vishay	8.5	9.44	14.4	347	5000	P600	Active
5KP8.5A-TP	Micro Commercial Co	8.5	9.44	14.4	347	5000	R-6	Active
5KP8.5AE3/TR13	Microchip Technology	8.5	9.44	14.4	347	5000	P600	Active
5KP8.5A	Littelfuse	8.5	9.44	14.4	354.2	5000	P600	Active
5KP8.5A-B	Littelfuse	8.5	9.44	14.4	354.2	5000	P600	Active
5KP8.5A-HR	Littelfuse	8.5	9.44	14.4	354.2	5000	P600	Active
5KP8.5A-HRA	Littelfuse	8.5	9.44	14.4	354.2	5000	P600	Active
5KP8.5E3/TR13	Microchip Technology	8.5	9.44	15.9	314	5000	P600	Active
SA8.5A	Taiwan Semiconductor	8.5	9.44	14.4	36	500	DO-204AC	Active

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement)

For applications requiring identical electrical performance and P600 axial package compatibility, the following active-status parts are direct equivalents:

5KP8.5A-E3/54 (Vishay, Tape & Reel) — Identical specifications to the original part with active production status and highest inventory availability (1900 pcs).
5KP8.5AHE3/54 (Vishay, Automotive Grade, AEC-Q101 qualified) — Suitable for automotive applications requiring AEC-Q101 certification.
5KP8.5AE3/TR13 (Microchip Technology, Tape & Reel) — Equivalent performance with active status and high inventory (917 pcs).
5KP8.5A (Littelfuse, Tape & Reel) — Highest inventory availability (300,100 pcs) with peak current of 354.2A, within acceptable tolerance for this application class.
5KP8.5A-HR and 5KP8.5A-HRA (Littelfuse, High Reliability Series) — Suitable for applications requiring enhanced reliability certifications.

Secondary Substitutes (Conditional Use)

5KP8.5A-B (Littelfuse, Bulk packaging) — Electrically equivalent but supplied in bulk format rather than tape & reel.
5KP8.5A-TP (Micro Commercial Co, R-6 package) — Equivalent electrical performance with R-6 axial package; suitable only if PCB layout accommodates R-6 footprint.

Limited Compatibility

5KP8.5E3/TR13 (Microchip Technology) — Voltage clamping increased to 15.9V with reduced peak current (314A). Use only if application tolerates higher clamping voltage.
SA8.5A (Taiwan Semiconductor, DO-204AC package) — Significantly reduced peak current (36A) and power rating (500W). Not suitable for high-energy transient suppression; applicable only to low-power signal-level protection.

Frequently Asked Questions (FAQ)

Q: Can I use 5KP8.5A-E3/54 as a direct replacement for 5KP8.5A-E3/51?

A: Yes. Both parts share identical electrical specifications (8.5V standoff, 14.4V clamping, 347A peak current, 5000W power rating) and P600 axial package configuration. The primary difference is product status: the original is obsolete while the substitute is in active production.

Q: What is the difference between Littelfuse 5KP8.5A variants (standard, -B, -HR, -HRA)?

A: All variants maintain identical electrical ratings. The differences are packaging format (-B indicates bulk; standard and -HR/-HRA are tape & reel) and reliability classification (HR and HRA series indicate high-reliability qualification). Selection depends on procurement requirements and application reliability standards.

Q: Is the Littelfuse 5KP8.5A with 354.2A peak current compatible with the original 347A specification?

A: Yes. The 354.2A peak current represents a 2% increase within normal manufacturing tolerance and does not affect circuit performance. Both parts maintain identical voltage ratings and power dissipation limits.

Q: Can I substitute SA8.5A for the 5KP8.5A-E3/51?

A: Not for equivalent protection. While SA8.5A shares the same 8.5V standoff and 14.4V clamping voltage, its peak current rating (36A) and power rating (500W) are substantially lower. SA8.5A is suitable only for low-power signal-level transient suppression, not for high-energy industrial or power-line applications.

Q: What is the significance of the package designation (P600 vs. R-6)?

A: Both P600 and R-6 are axial through-hole packages with identical electrical performance. The difference is physical footprint and lead spacing. Substitution between packages is possible only if PCB layout accommodates the alternative package dimensions. Verify footprint compatibility before selecting 5KP8.5A-TP (R-6 package).

Q: Does the Microchip 5KP8.5E3/TR13 with 15.9V clamping voltage affect circuit operation?

A: The increased clamping voltage (15.9V vs. 14.4V) provides less aggressive transient suppression. Use this part only if the protected circuit can tolerate higher transient voltage peaks. For applications requiring strict 14.4V clamping, select parts with matching voltage specifications.

Q: Are all substitute parts RoHS3 compliant?

A: All listed substitutes are RoHS3 compliant. Moisture Sensitivity Level (MSL) is 1 (Unlimited) for all parts, indicating no special moisture handling requirements during storage or assembly.

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