2N4118A

Jfets Overview

The Vishay Siliconix 2N4118A is an N-channel Junction Field-Effect Transistor (JFET) designed for ultra-high input impedance applications. It features a Gate-Source Cutoff Voltage (VGS(off)) ranging from -1 V to -3 V and a minimum Forward Transconductance (gfs) of 80 µS. The device exhibits a typical gate leakage current of 0.2 pA at room temperature, with a maximum limit of 1 pA. It supports a Gate-Source Breakdown Voltage of -40 V and operates within a junction temperature range of -55°C to 175°C.

Jfets Feature Summary

• Ultra-low gate leakage current typically operating at 0.2 pA
• Ultrahigh input impedance suitable for sensitive front-end amplifiers
• Hermetically sealed TO-206AF package available for military processing

Jfets Applications

• High-impedance transducer amplifiers
• Smoke detector inputs
• Infrared detector amplifiers
• Precision test equipment

Jfets Procurement Notes

Verify the specific ordering suffix to confirm the required package type, as the 2N prefix denotes the hermetically sealed TO-206AF (TO-72) metal can variant. Confirm that the procurement specification aligns with the intended thermal management requirements for the TO-206AF case power dissipation limits. Ensure compatibility with MIL-S-19500 standards if military-grade reliability is mandated for the application.

Jfets Selection Notes

Select the 2N4118A when circuit design requires an N-channel JFET with a moderate cutoff voltage between -1 V and -3 V. This component is appropriate for designs prioritizing minimal signal loss or error voltage when interfacing with high-impedance sources. Consider the physical dimensions and mounting constraints of the TO-206AF package during the layout phase.

Jfets Part Context

The 2N4118A belongs to the Vishay Siliconix 2N/PN/SST4117A series of N-channel JFETs. This family includes variants with different cutoff voltages, such as the 2N4117A and 2N4119A, allowing designers to select components based on specific biasing needs. The series is engineered to provide low noise performance and insignificant signal loss in critical analog signal paths.

Jfets Replacement Considerations

Compatible substitutes include the PN4118A (plastic TO-92 package) and SST4118 (surface-mount SOT-23 package). These variants share identical electrical characteristics but differ in packaging technology and thermal handling capabilities compared to the hermetically sealed 2N4118A.

Jfets FAQ

What is the typical gate leakage current for the 2N4118A?

The typical gate leakage current is 0.2 pA at room temperature, with a specified maximum limit of 1 pA.

Does the 2N4118A support military processing?

Yes, the hermetically sealed TO-206AF package allows for full military processing per MIL-S-19500.

What is the forward transconductance specification?

The minimum forward transconductance (gfs) is specified at 80 µS under standard test conditions.