Q4004LT

Triacs Overview

The Littelfuse Q4004LT is a Teccor Quadrac device, which integrates a triac and a diac trigger within a single TO-220AB package. It functions as a bidirectional AC switch with a rated repetitive off-state voltage (VDRM) of 400 V and an on-state RMS current (ITRMS) of 4 A. The device features a gate trigger current (IGT) of 1.2 A and maintains a maximum holding current (Ih) of 30 mA. Operating temperatures range from -40°C to +125°C. Key electrical parameters include a breakover voltage (VBO) between 33 V and 43 V, a non-repetitive peak on-state current of 46 A or 55 A, and an on-state voltage of 1.6 V. The component offers high noise immunity due to the internal trigger element.

Triacs Feature Summary

• Integrates a diac trigger element in series with the gate to eliminate external discrete components
• Provides electrical isolation of 2500 V rms from leads to mounting surface without external insulators
• Features glass-passivated junctions for long-term parameter stability and reliability
• Designed for applications requiring high noise immunity in AC switching circuits

Triacs Applications

• AC speed controls
• Temperature modulation controls
• Lighting controls

Triacs Procurement Notes

Verify component status before design finalization as the Q4004LT is listed as obsolete by the manufacturer. Confirm availability through authorized distributors or secondary markets if sourcing is required. Ensure that any replacement strategy accounts for the specific integration of the internal diac trigger, which differs from standard triacs. Validate RoHS compliance and UL recognition requirements against current project specifications.

Triacs Selection Notes

Select this component when circuit simplicity and noise immunity are prioritized over discrete assembly costs. The integrated diac simplifies phase control designs by removing the need for separate trigger networks. Consider the TO-220AB package for thermal management needs and the 400 V rating for appropriate voltage margins. Verify that the 1.2 A gate trigger current aligns with the driving circuit capabilities.

Triacs Part Context

The Q4004LT belongs to the Teccor Quadrac series developed by Littelfuse. These devices combine a triac and a diac in one package to streamline AC switching designs. The series includes variants with different voltage and current ratings, all sharing the benefit of built-in triggering. This integration reduces assembly time and component count compared to using separate triac and diac parts.

Triacs Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. As the component is marked obsolete, alternative solutions may require redesigning the trigger network if using a standard triac instead of a Quadrac device.