FJN3305RBU

Overview

The FJN3305RBU is an NPN epitaxial silicon transistor with built-in bias resistors, manufactured by onsemi. It features a collector-emitter voltage of 50 V and a continuous collector current of 100 mA. The device includes an input resistor (R1) with a typical value of 4.7 kΩ and a base-emitter resistor (R2) of 10 kΩ, resulting in a resistor ratio of 0.47. Key electrical characteristics include a DC current gain (hFE) of at least 30, a collector-emitter saturation voltage of 0.3 V, and a transition frequency of 250 MHz. It operates within a junction temperature range up to 150 °C and dissipates up to 300 mW.

Feature Summary

• Integrated bias network simplifies circuit design by eliminating external components
• High-speed switching capability supported by a 250 MHz transition frequency
• Low saturation voltage ensures efficient power handling during conduction

Applications

• Switching circuits
• Inverter applications
• Interface circuits
• Driver circuits

Procurement Notes

Verify the specific ordering suffix against official manufacturer documentation to confirm package type and tape-and-reel specifications. Ensure compatibility with RoHS directives and check for any lifecycle status changes such as obsolescence or last-time buy notices before finalizing procurement plans.

Selection Notes

Select this component when a single NPN transistor with integrated biasing is required for space-constrained designs. Verify that the 50 V collector-emitter rating and 100 mA current capacity meet the load requirements. Confirm that the 4.7 kΩ input resistance aligns with the driving source impedance for proper logic level interfacing.

Part Context

This part belongs to the FJN3305R series of Bias Resistor Built-In transistors. It serves as the NPN counterpart to the PNP FJN4305R device. Originally developed by Fairchild Semiconductor, the product line was transferred to onsemi following corporate acquisitions. The TO-92 package provides a compact solution for through-hole mounting.

Replacement Considerations

The FJN4305R is documented as the complementary PNP device within the same series. For direct NPN replacements, verify equivalent parameters such as 50 V VCEO, 100 mA IC, and similar R1/R2 ratios from other manufacturers offering BRT transistors in TO-92 packages.