Littelfuse V420LS40B Varistor: Equivalent & Substitute Parts

Part Overview

The Littelfuse V420LS40B is a 665 V, 6.5 kA disc varistor designed for transient voltage suppression in through-hole applications. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing production and maintenance requirements. The varistor operates across a temperature range of -55°C to 85°C and meets ROHS3 compliance standards. Substitute parts maintain identical electrical and mechanical specifications while offering active product status and improved availability.

Key Parameters

Parameter	Value
Varistor Voltage (Typical)	665 V
Varistor Voltage Range	610 V (Min) – 720 V (Max)
Maximum AC Voltage	420 V
Maximum DC Voltage	560 V
Current – Surge	6.5 kA
Energy Absorption	160 J
Capacitance @ 1 MHz	600 pF
Operating Temperature Range	-55°C to 85°C
Mounting Type	Through Hole
Package / Case	Disc 20mm
Number of Circuits	1
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the V420LS40B are classified as parametric equivalents based on strict electrical and mechanical compatibility criteria. All substitute parts maintain identical specifications across the following key parameters:

Varistor voltage range: 610 V (Min) – 720 V (Max), with 665 V typical
Maximum AC and DC voltage ratings: 420 V AC / 560 V DC
Surge current capacity: 6.5 kA
Energy absorption: 160 J
Capacitance: 600 pF @ 1 MHz
Operating temperature: -55°C to 85°C
Package form factor: Disc 20mm through-hole
Compliance: ROHS3 Compliant, MSL 1

Substitution differences are limited to packaging format (Tape & Reel vs. Cut Tape) and internal series designation (LS, LT, LU). These variations do not affect electrical performance or mechanical compatibility in circuit applications.

Parameter Comparison

Part Number	Series	Packaging	Product Status	Inventory (Pcs)	Varistor Voltage (Typ)	Max AC / DC Volts	Surge Current	Energy	Operating Temp	RoHS Status
V420LS40B	LS	Bulk	Obsolete	1157	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LS40BP	LS	Tape & Reel	Active	743	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LS40BPX10	LS	Tape & Reel	Active	1035	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LS40BPX2855	LS	Tape & Reel	Active	995	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LT40BP	LT	Cut Tape	Active	3883	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LT40BPX10	LT	Tape & Reel	Active	840	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LT40BPX2855	LT	Tape & Reel	Active	986	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LU40BP	LU	Tape & Reel	Active	758	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LU40BPX10	LU	Tape & Reel	Active	718	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3
V420LU40BPX2855	LU	Tape & Reel	Active	761	665 V	420 V / 560 V	6.5 kA	160 J	-55°C to 85°C	ROHS3

Engineering Selection Recommendations

All listed substitute parts are classified as active products with ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment for current manufacturing environments. The V420LS40B original part is obsolete; direct substitution is required for new production.

For applications requiring immediate component availability, V420LT40BP offers the highest inventory level (3883 units) while maintaining full electrical and mechanical equivalence. This part is supplied in Cut Tape packaging, suitable for manual assembly or standard pick-and-place operations.

For automated assembly workflows, Tape & Reel packaged variants (V420LS40BPX10, V420LS40BPX2855, V420LT40BPX10, V420LT40BPX2855, V420LU40BP, V420LU40BPX10, V420LU40BPX2855) provide standard reel configurations. The X10 and X2855 designations indicate different reel specifications; selection depends on existing assembly equipment compatibility.

All substitute parts maintain identical electrical performance: 665 V typical varistor voltage, 6.5 kA surge current capacity, 160 J energy absorption, and -55°C to 85°C operating temperature range. Circuit-level performance is not affected by series designation (LS, LT, LU) or packaging format.

Frequently Asked Questions (FAQ)

Q: Can V420LT40BP be used as a direct replacement for V420LS40B in existing designs?

A: Yes. Both parts share identical electrical specifications (665 V typical varistor voltage, 6.5 kA surge current, 160 J energy absorption) and mechanical form factor (Disc 20mm through-hole). The only difference is packaging format (Cut Tape vs. Bulk) and internal series designation, neither of which affects circuit performance.

Q: What is the difference between V420LS40BPX10 and V420LS40BPX2855?

A: Both parts are electrically and mechanically identical. The X10 and X2855 suffixes denote different reel specifications for automated assembly. Selection depends on compatibility with existing pick-and-place equipment. Consult equipment documentation for reel format requirements.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 Compliant certification and REACH Unaffected status, meeting current regulatory requirements for electronic component manufacturing and distribution.

Q: Why is V420LS40B marked as obsolete?

A: The V420LS40B is classified as obsolete by Littelfuse. Active equivalent parts with identical specifications are available as direct replacements. All substitute parts listed maintain full electrical and mechanical compatibility.

Q: Can packaging format affect circuit performance?

A: No. Packaging format (Bulk, Cut Tape, or Tape & Reel) affects only component handling and assembly logistics. Electrical performance and mechanical compatibility remain unchanged across all packaging variants.

Q: Which substitute part offers the best availability?

A: V420LT40BP provides the highest current inventory (3883 units) and is supplied in Cut Tape format. For Tape & Reel requirements, V420LS40BPX10 and V420LT40BPX2855 offer strong availability (1035 and 986 units respectively).

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