TMA256B-L

Overview

The TMA256B-L is a bidirectional triode thyristor (triac) from the TMA25x series, designed for AC power control applications. It features a peak repetitive off-state voltage (VDRM) of 600 V and a peak non-repetitive off-state voltage (VDSM) of 700 V. The device supports an RMS on-state current (IT(RMS)) of 25 A at a case temperature of 83°C, with surge capabilities reaching 263 A at 60 Hz. It operates within a junction temperature range of -40°C to 125°C and provides an isolation voltage of 2000 V AC RMS between lead and case. Packaged in a 3-pin TO-3PF SIP with heatsink mounting, it offers improved commutation dv/dt characteristics.

Feature Summary

• High thermal dissipation capability via fully-molded SIP package with heatsink mounting
• Enhanced isolation voltage of 2000 V AC RMS guaranteed for up to 1 minute
• Improved commutation dv/dt and critical rising rate of off-state voltage during commutation
• Uniform switching performance suitable for full-cycle AC applications

Applications

• Residential and commercial appliances including vacuum cleaners, rice cookers, TVs, and home entertainment systems
• White goods such as washing machines requiring two-phase motor control
• Office automation power control for photocopiers and laser beam printers
• Temperature control and light dimming circuits
• General use switching mode power supplies (SMPS) for in-rush current control

Procurement Notes

Verify component authenticity by checking manufacturer markings against official datasheet specifications. Confirm the part number suffix matches the required voltage rating and UL recognition status. Ensure storage conditions remain within standard temperature and humidity limits to prevent lead rust or solderability issues before installation.

Selection Notes

Select the TMA256B-L when a 600 V blocking voltage is required for AC power control. Consider the 25 A RMS current rating relative to the expected load and ambient temperature derating curves. Verify that the application requires the specific TO-3PF package form factor and heatsink mounting interface for adequate thermal management.

Part Context

The TMA256B-L belongs to the TMA25x series of triacs manufactured by Sanken Electric Co., Ltd. and distributed by Allegro MicroSystems, Inc. This series is positioned for general-purpose electronic equipment and household appliances. The 'L' suffix denotes the specific packaging variant without UL recognition compared to the 'I' suffix version.

Replacement Considerations

The TMA254B-L serves as a lower voltage alternative within the same series offering 400 V VDRM. Designers must verify that the replacement meets the circuit's voltage requirements and thermal constraints. Cross-reference pinouts and package dimensions to ensure mechanical compatibility.