T106B1 Equivalent & Substitute Parts

Part Overview

The T106B1 is a Sensitive Gate SCR (Silicon Controlled Rectifier) rated for 200V off-state voltage and 4A RMS current, manufactured by Littelfuse Inc. in a TO-202 through-hole package. This component is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements. The part remains available in inventory (681 pcs), but obsolescence status necessitates identification of active alternative components that maintain functional compatibility within specified electrical parameters.

Substiute Parts

T106B1

Littelfuse Inc.In Stock: 773T106B1 Datasheet

Current PartRFQ

S4004VS2TP

Littelfuse Inc.In Stock: 2208S4004VS2TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the T106B1 is determined by the following critical electrical and mechanical parameters:

Gate Trigger Characteristics: Both the main part and substitute must maintain identical gate trigger voltage (Vgt Max: 800 mV) and gate trigger current (Igt Max: 200 µA) to ensure compatible gate drive circuits and control logic.

Current Rating: The substitute must support the same RMS current rating (4A) to maintain thermal and electrical performance in the application circuit.

SCR Type: Both components must be Sensitive Gate SCRs to preserve gate sensitivity and control characteristics.

Operating Temperature: The substitute must support the full operating temperature range (-40°C to 110°C) for thermal compatibility.

Compliance & Certifications: Both components must maintain ROHS3 compliance and equivalent moisture sensitivity levels (MSL 1) for manufacturing and environmental requirements.

Off-State Voltage Consideration: While the T106B1 is rated for 200V off-state, the substitute S4004VS2TP is rated for 400V off-state. This represents an uprated component that maintains backward compatibility—a 400V-rated SCR can operate safely in 200V applications with improved voltage margin and reliability.

Parameter Comparison

Engineering Selection Recommendations

The S4004VS2TP is the manufacturer-recommended substitute for the T106B1. Selection is based on the following engineering criteria:

Electrical Compatibility: Gate trigger parameters (Vgt and Igt) are identical, ensuring direct compatibility with existing gate drive circuits. The RMS current rating (4A) matches the original specification. The uprated off-state voltage (400V vs. 200V) provides improved voltage margin and reliability in 200V applications without compromising performance.

Thermal Performance: The on-state voltage (Vtm) of the S4004VS2TP (1.6V max) is lower than the T106B1 (2.2V max), resulting in reduced power dissipation and improved thermal characteristics.

Compliance & Longevity: Both components are ROHS3 compliant with MSL 1 ratings. The S4004VS2TP carries active product status, ensuring long-term availability and supply chain stability compared to the obsolete T106B1.

Package Consideration: The S4004VS2TP uses a TO-251AA package (short leads, IPak) instead of the TO-202 Long Tab. This requires PCB layout modification for pin placement and thermal management. Both are through-hole packages suitable for standard PCB assembly processes.

Frequently Asked Questions (FAQ)

Q: Can the S4004VS2TP directly replace the T106B1 without circuit modifications?

A: Electrical substitution is direct—gate trigger parameters, current ratings, and operating temperature ranges are identical. However, the package change from TO-202 to TO-251AA requires PCB layout modification for hole placement and lead spacing. No circuit schematic changes are necessary.

Q: Why is the S4004VS2TP rated for 400V when the T106B1 is only 200V?

A: The S4004VS2TP is an uprated component that maintains all gate trigger and current specifications while providing higher voltage capability. This is a direct upgrade that improves reliability and voltage margin in 200V applications. The higher voltage rating does not affect performance in circuits designed for 200V operation.

Q: Are the gate drive requirements identical between these two parts?

A: Yes. Both components have identical gate trigger voltage (800 mV max) and gate trigger current (200 µA max) specifications. Existing gate drive circuits require no modification.

Q: What is the impact of the lower on-state voltage (Vtm) in the S4004VS2TP?

A: The lower on-state voltage (1.6V vs. 2.2V) reduces power dissipation during conduction, resulting in lower heat generation and improved thermal performance. This is a beneficial characteristic that does not affect circuit compatibility.

Q: Are both components suitable for the same operating temperature range?

A: Yes. Both the T106B1 and S4004VS2TP support the full operating temperature range of -40°C to 110°C. Thermal management and derating curves should be evaluated based on the specific application and PCB layout.

Q: What are the key differences in surge current ratings?

A: The T106B1 is rated for 16A/20A (50/60 Hz) non-repetitive surge current, while the S4004VS2TP is rated for 25A/30A. The higher surge rating in the substitute provides additional margin for transient events and improves robustness in applications with inductive switching.