BT149D,126

Scrs Overview

The BT149D,126 is a planar passivated Silicon Controlled Rectifier (SCR) manufactured by WeEn Semiconductors. It is housed in a SOT54 (TO-92) plastic package and designed for direct interfacing with microcontrollers, logic ICs, and low-power gate trigger circuits. Key electrical parameters include a maximum repetitive peak off-state voltage of 400 V, an average on-state current of 0.5 A, and an RMS on-state current of 0.8 A. The device features a maximum gate trigger current of 0.2 mA and a critical rate of rise of off-state voltage of 500 V/µs. The maximum junction temperature is rated at 125°C.

Scrs Feature Summary

• Sensitive gate design allows direct interface with microcontrollers and logic ICs without additional driver circuitry.
• Planar passivated construction provides robust performance for general-purpose switching applications.
• Glass passivation ensures reliability in phase control environments.

Scrs Applications

• General purpose switching
• Phase control applications
• Low power gate trigger circuits

Scrs Procurement Notes

Verify the specific ordering suffix to confirm packaging configuration. The '126' suffix indicates Ammopack, Radial packing. Confirm RoHS compliance status and lead-free plating requirements against project specifications. Ensure the industrial qualification level meets environmental operating conditions. Cross-reference the 12NC code for accurate supply chain tracking.

Scrs Selection Notes

Select this component when a sensitive gate SCR is required for logic-level triggering. The 400 V rating suits low-voltage AC control systems. The TO-92 package is suitable for through-hole mounting where space is limited but high current is not required. Compare the 0.5 A average current limit against load requirements to ensure adequate thermal margin during continuous operation.

Scrs Part Context

This part belongs to the BT149 series of thyristors from WeEn Semiconductors, formerly Philips/NXP. The series includes variants with different voltage ratings, such as the BT149G which offers a 600 V rating. These devices are standardized for logic-level compatibility, distinguishing them from standard SCRs that require higher gate currents for activation.

Scrs Replacement Considerations

The BT149G is a compatible alternative within the same family offering a higher voltage rating of 600 V while maintaining identical current and package characteristics. Other similar logic-level thyristors include the BT148 and BT169 series, though pinouts and specific electrical limits should be verified before substitution.