Littelfuse V56ZS3 56V 500A Varistor Equivalent & Substitute Parts

Part Overview

The Littelfuse V56ZS3 is a 56 V, 500 A transient voltage suppressor varistor in a through-hole disc 10mm package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The varistor provides transient voltage suppression across a single circuit with a nominal varistor voltage of 56 V and surge current rating of 500 A. Direct substitutes and parametric equivalents from Littelfuse maintain identical electrical and mechanical specifications while offering active product status and improved availability.

Key Parameters

Parameter	Value
Varistor Voltage (Typical)	56 V
Current - Surge	500 A
Maximum AC Volts	35 V
Maximum DC Volts	45 V
Energy	5.5 J
Capacitance @ 1 MHz	2150 pF
Operating Temperature Range	-55°C to 85°C
Mounting Type	Through Hole
Package / Case	Disc 10mm
Number of Circuits	1

Substitute Part Grouping Explanation

Substitution of the V56ZS3 is determined by strict equivalence across all electrical and mechanical parameters. The following criteria define valid substitutes:

Varistor voltage range: 50.4 V (minimum) to 61.6 V (maximum)
Surge current capacity: 500 A
Maximum AC voltage rating: 35 V
Maximum DC voltage rating: 45 V
Energy absorption: 5.5 J
Capacitance at 1 MHz: 2150 pF
Operating temperature: -55°C to 85°C
Mounting configuration: Through hole
Package form factor: Disc 10mm
Circuit count: 1

All substitute parts listed maintain these specifications. Differences exist only in product series designation (ZS, ZT, ZU), packaging format (bulk versus tape & reel), and product status (obsolete versus active).

Parameter Comparison

Part Number	Manufacturer	Series	Product Status	Packaging	Varistor Voltage (Typ)	Surge Current	Max AC / DC Volts	Energy	Capacitance @ 1 MHz	Operating Temp	RoHS Status
V56ZS3	Littelfuse Inc.	ZS	Obsolete	Bulk	56 V	500 A	35 V / 45 V	5.5 J	2150 pF	-55°C to 85°C	ROHS3 Compliant
V56ZS3P	Littelfuse Inc.	ZS	Active	Tape & Reel	56 V	500 A	35 V / 45 V	5.5 J	2150 pF	-55°C to 85°C	ROHS3 Compliant
V56ZS3PX2855	Littelfuse Inc.	ZS	Active	Tape & Reel	56 V	500 A	35 V / 45 V	5.5 J	2150 pF	-55°C to 85°C	ROHS3 Compliant
V56ZT3P	Littelfuse Inc.	ZT	Active	Tape & Reel	56 V	500 A	35 V / 45 V	5.5 J	2150 pF	-55°C to 85°C	ROHS3 Compliant
V56ZT3PX2855	Littelfuse Inc.	ZT	Active	Tape & Reel	56 V	500 A	35 V / 45 V	5.5 J	2150 pF	-55°C to 85°C	ROHS3 Compliant
V56ZU3P	Littelfuse Inc.	ZU	Active	Tape & Reel	56 V	500 A	35 V / 45 V	5.5 J	2150 pF	-55°C to 85°C	ROHS3 Compliant
V56ZU3PX2855	Littelfuse Inc.	ZU	Active	Tape & Reel	56 V	500 A	35 V / 45 V	5.5 J	2150 pF	-55°C to 85°C	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts are manufactured by Littelfuse Inc. and maintain full parametric equivalence to the V56ZS3. Selection between substitutes is based on the following factors:

Product Status: The V56ZS3 is obsolete. All substitute parts carry active product status, ensuring long-term availability and manufacturing support.

Packaging Format: The original V56ZS3 is supplied in bulk packaging. Substitutes V56ZS3P, V56ZS3PX2855, V56ZT3P, V56ZT3PX2855, V56ZU3P, and V56ZU3PX2855 are supplied in tape & reel format, suitable for automated assembly processes.

Compliance: All parts are ROHS3 compliant. Substitute parts carry REACH Unaffected status, confirming regulatory compliance across international markets.

Series Variants: The ZS, ZT, and ZU series designations indicate internal manufacturing process variations within Littelfuse's varistor product line. All three series maintain identical electrical performance and mechanical form factor for the 56 V, 500 A specification.

Inventory Availability: Active substitute parts demonstrate current manufacturing and stock availability, ranging from 670 to 947 units in inventory.

Frequently Asked Questions (FAQ)

Q: Can I use any of these substitute parts as a direct replacement for the V56ZS3?

A: Yes. All listed substitute parts maintain identical electrical specifications (56 V nominal varistor voltage, 500 A surge current, 5.5 J energy absorption) and mechanical form factor (through-hole disc 10mm package). The primary difference is product status and packaging format.

Q: What is the difference between the ZS, ZT, and ZU series?

A: These designations represent different manufacturing series within Littelfuse's varistor product line. All three series deliver identical electrical and thermal performance for the 56 V, 500 A specification. Selection between series is based on availability and procurement preference.

Q: Why are some part numbers suffixed with "PX2855"?

A: The PX2855 suffix indicates a specific tape & reel packaging configuration. Parts with and without this suffix (e.g., V56ZS3P versus V56ZS3PX2855) are electrically and mechanically identical; the suffix denotes packaging reel specifications for automated assembly.

Q: Is the V56ZS3 still available?

A: The V56ZS3 is classified as obsolete. However, 1134 units remain in stock as new original inventory. For new designs or long-term production, active substitute parts are recommended.

Q: What are the key parameters I need to verify when selecting a substitute?

A: Verify the following parameters match your application requirements: varistor voltage (56 V nominal), surge current (500 A), maximum AC voltage (35 V), maximum DC voltage (45 V), energy absorption (5.5 J), operating temperature range (-55°C to 85°C), and through-hole disc 10mm package form factor.

Q: Are all substitute parts ROHS compliant?

A: Yes. All substitute parts are ROHS3 compliant and carry REACH Unaffected status, meeting international environmental and regulatory requirements.

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