L4X5 TRIAC Equivalent & Substitute Parts

Part Overview

The L4X5 is a Logic - Sensitive Gate TRIAC manufactured by Littelfuse Inc., rated for 400 V off-state voltage and 800 mA on-state current in a DO-214AA surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Substiute Parts

L4X5

Littelfuse Inc.In Stock: 1154L4X5 Datasheet

Current PartRFQ

L4X5RP

Littelfuse Inc.In Stock: 799L4X5RP Datasheet

DirectRFQ

BT1308W-600D,115

WeEn SemiconductorsIn Stock: 7129BT1308W-600D,115 Datasheet

MFR RecommendedRFQ

Z0103MN,135

WeEn SemiconductorsIn Stock: 50927Z0103MN,135 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the L4X5 TRIAC is determined by the following critical parameters:

Primary Substitution Criteria:

• Triac Type: Logic - Sensitive Gate configuration
• Voltage - Off State: Minimum 400 V (higher voltage ratings are acceptable for voltage derating applications)
• Current - On State (It (RMS)): Minimum 800 mA (equal or higher ratings acceptable)
• Mounting Type: Surface Mount
• Package compatibility: DO-214AA or equivalent surface mount packages

Secondary Compatibility Factors:

• Gate trigger voltage (Vgt) and current (Igt) characteristics must support the intended gate drive circuit
• Operating temperature range must meet application requirements
• RoHS compliance status for regulatory alignment

Two substitute categories are identified:

1. Direct Equivalent (Same Voltage Rating): L4X5RP - Identical electrical specifications with active product status and improved packaging availability
2. Higher Voltage Rated Substitutes: BT1308W-600D,115 and Z0103MN,135 - Both rated for 600 V off-state voltage, suitable for applications where voltage derating is acceptable

Parameter Comparison

Engineering Selection Recommendations

L4X5RP (Littelfuse Inc.) is the primary substitute for the L4X5. This part maintains identical electrical specifications and package form factor while offering active product status and improved long-term availability. Selection of L4X5RP requires no circuit modifications and provides direct compatibility.

BT1308W-600D,115 (WeEn Semiconductors) is suitable for applications where 600 V voltage derating is acceptable. This part features a higher maximum operating temperature (125°C vs. 110°C) and increased voltage margin. Package transition from DO-214AA to TO-261-4 requires PCB layout modification. Gate trigger voltage (Vgt) maximum of 2 V versus 1.3 V for the L4X5 may require gate drive circuit evaluation.

Z0103MN,135 (WeEn Semiconductors) offers the highest current rating (1 A) and lowest gate trigger current (Igt) at 3 mA maximum. This part is suitable for applications requiring enhanced current capacity or lower gate drive requirements. Like BT1308W-600D,115, it requires package transition from DO-214AA to TO-261-4 and operates at 125°C maximum junction temperature. The 600 V voltage rating provides additional derating margin.

All substitute parts maintain ROHS3 or RoHS compliance and are classified as active products with established supply chains.

Frequently Asked Questions (FAQ)

Q: Can L4X5RP be used as a direct replacement for L4X5?

A: Yes. L4X5RP is electrically and mechanically identical to L4X5, with the same 400 V voltage rating, 800 mA current rating, and DO-214AA package. The primary difference is product status (active vs. obsolete) and packaging format (Tape & Reel vs. bulk).

Q: What are the implications of using a 600 V rated TRIAC (BT1308W-600D,115 or Z0103MN,135) in place of the 400 V L4X5?

A: Higher voltage-rated TRIACs can be used in 400 V applications through voltage derating. The 600 V rating provides additional safety margin and is acceptable for designs operating at or below 400 V. No circuit modifications are required from an electrical standpoint, but PCB layout changes are necessary due to package differences (TO-261-4 vs. DO-214AA).

Q: Are there package compatibility issues between L4X5 and the substitute parts?

A: L4X5RP uses the same DO-214AA package as L4X5 and requires no layout changes. BT1308W-600D,115 and Z0103MN,135 use TO-261-4 packages, which have different pin spacing and footprint dimensions. PCB redesign is required for these substitutes.

Q: What is the difference between BT1308W-600D,115 and Z0103MN,135?

A: Both are 600 V rated TRIACs with similar gate characteristics. Z0103MN,135 offers higher on-state current (1 A vs. 800 mA) and lower gate trigger current (3 mA vs. 5 mA). BT1308W-600D,115 has a maximum gate trigger voltage of 2 V compared to 1.3 V for Z0103MN,135. Selection depends on specific gate drive circuit requirements and current capacity needs.

Q: Do all substitute parts meet RoHS compliance?

A: Yes. L4X5RP and BT1308W-600D,115 are ROHS3 compliant. Z0103MN,135 is RoHS compliant. Both compliance levels are acceptable for most applications.

Q: What is the operating temperature difference between L4X5 and the 600 V substitutes?

A: L4X5 operates from -40°C to 110°C junction temperature. BT1308W-600D,115 and Z0103MN,135 operate to 125°C junction temperature. The higher temperature rating of the substitutes provides additional thermal margin in high-temperature applications.