FJN4305RBU

Overview

The FJN4305RBU is a PNP epitaxial silicon transistor manufactured by Fairchild Semiconductor, distributed under the onsemi brand. It features built-in bias resistors (R1=4.7kΩ, R2=10kΩ) for simplified circuit design. The device supports a collector-emitter voltage of -50V and a continuous collector current of -100mA. Key electrical parameters include a DC current gain (hFE) minimum of 30 at -5mA, a saturation voltage of -0.3V at -10mA, and a transition frequency of 200MHz. It operates within a junction temperature range up to 150°C and is housed in a TO-92 package.

Feature Summary

• Integrated bias resistor network with a ratio of approximately 2.13
• Designed for high-speed switching applications
• Complements the NPN FJN3305R transistor

Applications

• Switching circuits
• Inverter stages
• Interface circuits
• Driver circuits

Procurement Notes

Verify the manufacturer origin as Fairchild Semiconductor when sourcing from distributors listing it under the onsemi portfolio. Confirm the specific suffix 'BU' corresponds to the standard TO-92 configuration documented in the official datasheet. Ensure compliance with RoHS standards if required by the application specifications.

Selection Notes

Select this component for low-power PNP switching tasks requiring integrated base drive. The built-in resistors reduce external component count compared to discrete transistors. Verify that the -50V rating and -100mA current limit meet the load requirements. Consider the TO-92 package constraints for thermal dissipation in enclosed environments.

Part Context

This part belongs to the FJN series of pre-biased bipolar transistors. It serves as the PNP counterpart to the FJN3305R. The series is designed to simplify driver stage layouts by eliminating external base resistors while maintaining standard switching performance characteristics typical of small-signal transistors.

Replacement Considerations

The FJN3305R is the complementary NPN device within the same family. For direct replacement, verify pinout compatibility and ensure the target application does not require higher voltage or current ratings than the original design intended.