BRT21M

Overview

The BRT21M is a phototriac output optocoupler featuring zero-crossing detection, designed to isolate low-voltage logic from AC mains. It provides high input sensitivity with a trigger current (IFT) of less than 3 mA and supports an RMS on-state current (ITRMS) of 300 mA. The device offers high static dV/dt immunity of 10,000 V/µs and electrical insulation between input and output circuits. It is microcomputer compatible and available in surface mount packages.

Feature Summary

• Integrates zero-voltage crossing detection for precise phase-angle control
• Provides high input sensitivity with low trigger current requirements
• Ensures reliable isolation with high static dV/dt immunity

Applications

• Control of resistive, inductive, or capacitive loads on AC lines
• Solid-state relays requiring zero-crossing switching
• Microcomputer interface circuits for AC power management

Procurement Notes

Verify the specific suffix against official Vishay documentation to confirm package type and tape-and-reel specifications. Ensure the selected variant matches the required trigger current threshold and isolation voltage ratings for the target application circuit design.

Selection Notes

Select this component when zero-crossing functionality is required to minimize electromagnetic interference during AC load switching. Consider the 300 mA ITRMS rating for load capacity and verify compatibility with the controlling logic voltage levels due to the specific input sensitivity characteristics.

Part Context

This part belongs to the BRT21/BRT22/BRT23 family of Vishay phototriac output optocouplers. The family variants are distinguished primarily by their input trigger current thresholds, allowing designers to choose the appropriate sensitivity level for different logic families while maintaining consistent output performance and isolation characteristics.

Replacement Considerations

Substitutes within the same Vishay family include BRT21H and BRT21F, which offer different trigger current sensitivities. Verify that the alternative part's IFT specification aligns with the driving circuit's output capabilities before implementation.