FJX4001RTF

Overview

The FJX4001RTF is a PNP epitaxial silicon transistor with built-in bias resistors, packaged in SOT-323. It features a collector-base voltage (VCBO) and collector-emitter voltage (VCEO) of -50 V, with an emitter-base voltage (VEBO) of -10 V. The maximum continuous collector current (IC) is -100 mA, and power dissipation (PC) reaches 200 mW at 25°C ambient temperature. The junction temperature (TJ) limit is 150 °C. Electrical characteristics include a DC current gain (hFE) of 20 at IC = -10 mA, saturation voltage (VCE(sat)) of -0.3 V at IC = -10 mA, and a transition frequency (fT) of 200 MHz. Internal resistors R1 and R2 are nominally 4.7 kΩ.

Feature Summary

• Integrated bias network with dual resistors for simplified circuit design
• High-speed switching capability with 200 MHz transition frequency
• Compact surface-mount SOT-323 package suitable for space-constrained applications

Applications

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

Procurement Notes

Verify the component status carefully as the source datasheet indicates this part may be obsolete or not recommended for new designs. Confirm availability through authorized distributors and check for end-of-life notifications. Ensure the ordering suffix matches the required tape-and-reel packaging specifications for automated assembly processes.

Selection Notes

Select this component when a PNP transistor with integrated base drive resistors is required to reduce external component count. Verify that the -50 V voltage rating and -100 mA current capacity meet the specific load requirements. Consider the thermal derating curve if operating above 25°C ambient temperature to ensure the 200 mW power dissipation limit is not exceeded.

Part Context

The FJX4001R is a PNP epitaxial silicon transistor manufactured by Fairchild Semiconductor, now part of onsemi. It belongs to a family of bias resistor built-in transistors designed for general-purpose switching applications. The device serves as a complement to the NPN type FJX3001R, offering matched performance characteristics for complementary push-pull configurations.

Replacement Considerations

Check for direct pin-compatible replacements from onsemi or other manufacturers that maintain the same SOT-323 footprint and electrical ratings. Verify internal resistor values match the original 4.7 kΩ specification to ensure circuit compatibility.