2N4118A TO-72 4L ROHS

Jfets Overview

The 2N4118A is an N-channel silicon small-signal Junction Field-Effect Transistor (JFET) housed in a hermetically sealed TO-72 package. Designed for ultra-high input impedance applications, it features a gate leakage current typically operating at 0.2 pA with a maximum limit of 1 pA. The device specifies a drain-to-source saturation current (IDSS) minimum of 0.08 mA and a gate-to-source cutoff voltage (VGS(off)) minimum of -1 V. It provides forward transconductance (GFS) with a minimum value of 80 μS. These parameters make the component suitable for high-impedance sensitive front-end amplifier circuits where minimal circuit loading is required.

Jfets Feature Summary

• Ultra-high input impedance characteristics with negligible signal loss
• Hermetically sealed TO-72 package construction
• Low power consumption design
• Minimum circuit loading capability

Jfets Applications

• High-impedance sensitive front-end amplifiers
• Mid to high frequency designs requiring ultra-high input impedance
• Military applications utilizing hermetically sealed packages

Jfets Procurement Notes

Verify the manufacturer designation as Linear Integrated Systems or Micross when sourcing this component. Confirm the specific ordering suffix corresponds to the desired packaging format, such as bulk TO-72 units or surface mount SMP variants. Ensure the part meets the specified electrical limits for IDSS and VGS(off) required by the target circuit design before finalizing procurement.

Jfets Selection Notes

Select the 2N4118A over other JFETs when the application demands extremely low gate leakage currents around 1 pA. Compare the -1 V minimum cutoff voltage against source requirements to ensure proper biasing. Consider the TO-72 package if environmental sealing is necessary, or evaluate SMP alternatives for surface mount integration while maintaining equivalent electrical performance.

Jfets Part Context

This component belongs to a family of Interfet N-channel JFETs including the 2N4117A and 2N4119A. While sharing similar ultra-high impedance technologies, the 2N4118A offers intermediate specifications between the lower cutoff voltage of the 2N4117A and the higher current capabilities of the 2N4119A. It serves as a direct replacement for legacy Siliconix devices in established designs.

Jfets Replacement Considerations

The datasheet identifies this part as a direct replacement for the Siliconix 2N4117A. Verify pinout compatibility and thermal dissipation limits when substituting. Surface mount equivalents include the SMP4118 series.