HT32A

Overview

The Littelfuse HT32A is a standard bidirectional DIAC trigger thyristor designed for phase control applications. It operates within a breakover voltage range of 28V to 36V at 50/60Hz sine wave conditions. The device features a maximum pulse on-state current of 1.5A (120PPS, 10μs width) and supports an operating junction temperature range from -40°C to +125°C. Power dissipation is rated at 250mW between -40°C and +40°C, with derating required above this threshold. The component utilizes a DO-35 glass case package.

Feature Summary

• Bidirectional triggering capability for full-wave phase control circuits
• High reliability through improved junction construction and white wafer selections
• Robust resistance against junction contamination

Applications

• Lamp dimming phase control circuits
• Universal motor speed control systems
• Heat control applications
• Solid state ballast lighting controls

Procurement Notes

Verify the specific ordering suffix to confirm the packaging format. A blank suffix indicates bulk packing in boxes of 5000 units, while the RP suffix denotes tape and reel packaging containing 5000 units per reel. Confirm that the selected variant matches the required physical package dimensions for your PCB layout.

Selection Notes

Select the HT32A when a breakover voltage between 28V and 36V is required for triggering triacs or SCRs. Ensure the circuit design accommodates the 1.5A peak on-state current limit under specified pulse conditions. Verify thermal management requirements, as power dissipation must be derated by 3.6mW/°C for ambient temperatures exceeding 40°C.

Part Context

The HT32A belongs to the HTxxx & HTMxxx & STxxx series of standard bidirectional DIAC triggers manufactured by Littelfuse's Teccor brand. This series provides a range of voltage characteristics from 27V to 70V. The HT32A specifically corresponds to the 32A voltage designation within this family of bilateral trigger diacs.

Replacement Considerations

Direct substitutes within the same Littelfuse series include HT32B (30V-34V), HT34B (32V-36V), and HT35 (30V-40V). Cross-manufacturer equivalents such as DB3 or DB3A may function similarly but require verification of breakover voltage symmetry and current ratings against the original specifications.