BCY59X

Overview

The BCY59X is a single NPN bipolar junction transistor manufactured by STMicroelectronics. It features a maximum collector-emitter voltage of 45 V and a continuous collector current rating of 200 mA. The device operates with a transition frequency of 200 MHz and dissipates up to 390 mW of power. It is housed in a TO-18 metal can package for through-hole mounting. The component supports a maximum junction temperature of 175°C and exhibits a DC current gain of at least 180 at 2 mA and 5 V.

Feature Summary

• NPN configuration designed for general-purpose switching and amplification applications
• Hermetic TO-18 metal can package suitable for high-reliability environments
• High transition frequency capability supporting radio frequency signal processing

Applications

• Radio frequency amplifier circuits
• General-purpose switching applications
• Audio signal amplification stages

Procurement Notes

Verify the specific ordering suffix against the manufacturer datasheet to confirm pinout compatibility and electrical tolerances. Confirm RoHS3 compliance status if environmental regulations apply to the final assembly. Check component availability as the part may be classified as obsolete or end-of-life by the manufacturer. Ensure the TO-18 package dimensions match the target PCB footprint requirements.

Selection Notes

Select this component when a hermetically sealed NPN transistor is required for high-frequency operation. The TO-18 package provides superior thermal dissipation compared to plastic equivalents. Consider the 45 V breakdown voltage and 200 mA current limits to ensure adequate headroom for the intended circuit load. Verify that the 390 mW power dissipation rating aligns with the thermal management strategy of the design.

Part Context

The BCY59X belongs to the BCY59 family of discrete semiconductors produced by STMicroelectronics. This series utilizes planar technology to achieve reliable performance in demanding electronic environments. The component serves as a fundamental building block for analog and digital circuits requiring robust NPN switching characteristics.

Replacement Considerations

Consult official substitution guides for equivalent NPN transistors in TO-18 packages. Verify that any alternative part matches the 45 V voltage rating, 200 mA current capacity, and 200 MHz frequency response. Ensure physical pinout compatibility before integrating substitute components into existing designs.