BCX19LT1

Overview

The BCX19LT1 is a single PNP silicon small-signal transistor manufactured by onsemi (formerly Motorola). It is housed in a surface-mount SOT-23 package. The device supports a continuous collector current of 500 mA and features a collector-emitter breakdown voltage of 45 Vdc. Key electrical characteristics include a DC current gain ranging from 40 to 600, a collector-emitter saturation voltage of 0.62 Vdc at high currents, and a base-emitter on voltage of 1.2 Vdc. Thermal ratings specify a maximum junction temperature of +150°C and total device dissipation of 225 mW on standard FR-5 boards.

Feature Summary

• Single PNP bipolar junction transistor configuration
• Surface-mount SOT-23 packaging for compact integration
• High DC current gain capability for signal amplification
• Robust thermal performance with elevated junction temperature limits

Applications

• General-purpose switching circuits
• Small-signal amplification stages
• Low-power analog applications

Procurement Notes

Verify the specific manufacturer origin, as the component was originally produced by Motorola before its semiconductor division became onsemi. Confirm that the ordering suffix LT1 corresponds to the SOT-23 tape-and-reel packaging format. Ensure compatibility with RoHS directives if required by the target assembly process. Cross-reference datasheet revisions to confirm pinout consistency.

Selection Notes

Select this component when a PNP transistor with moderate voltage handling and high current capacity is required in a minimal footprint. The SOT-23 form factor suits space-constrained designs. Evaluate the thermal resistance requirements against the intended PCB copper area, as power dissipation is heavily dependent on board material and pad size.

Part Context

This part belongs to the BCX17/18/19/20 series of small-signal transistors. These devices share identical physical dimensions and pin configurations but differ primarily in their collector-emitter breakdown voltage ratings. The BCX19 variant specifically provides a 45 V rating, distinguishing it from lower-voltage siblings like the BCX17 or higher-voltage options within the same family.

Replacement Considerations

Compatible substitutes include BCX19LT1G and BCX19LTA1G. Verify that replacement parts maintain the same SOT-23 footprint and PNP polarity. Check for any changes in thermal resistance or electrical tolerances that might affect circuit performance.