SMP4340

Overview

The SMP4340 is an N-channel JFET utilizing InterFET N0016H geometry, designed for sensitive amplifier stages. It features a gate-to-source breakdown voltage of -50V and a drain-to-source saturation current (IDSS) range of 1.2mA to 3.6mA at VGS=0V. The device exhibits low input capacitance (Ciss) of 7pF typical and forward transconductance (GFS) between 1300μS and 3000μS. Maximum ratings include a continuous power dissipation of 350mW in the SOT-23 package and an operating junction temperature up to 150°C.

Feature Summary

• Utilizes proprietary N0016H geometry for exceptionally high radiation tolerance
• Provides extremely low gate leakage with typical values less than 1pA at room temperatures
• Delivers low noise performance with a typical figure of 3.5 nV/√Hz
• Features low input capacitance (Ciss) of 3pF typical for high-frequency signal integrity

Applications

• Radar systems and military communications equipment
• Satellites and missile guidance systems
• Hydrophone preamplifiers and medical imaging systems
• General-purpose amplifiers, switches, and oscillators

Procurement Notes

Verify that the specific ordering suffix matches the required packaging format, such as bulk SOT-23 or tape and reel quantities. Confirm compliance requirements including RoHS, REACH, and CMR status. Ensure the design accounts for the interchangeable source/drain pins characteristic of this component family. Validate thermal derating parameters against the maximum operating junction temperature limits specified for surface mount applications.

Selection Notes

Select the SMP4340 when low gate leakage and high radiation hardness are critical for mid-frequency amplifier designs. Compare IDSS ranges against circuit biasing requirements to ensure proper cutoff characteristics. Consider the SOT-23 package constraints regarding power dissipation and thermal management compared to through-hole alternatives like TO-18 or TO-92.

Part Context

The SMP4340 belongs to the 2N4340 series of N-channel JFETs manufactured by InterFET. It shares specifications with the 2N4341 but differs in binning thresholds for parameters like cutoff voltage and saturation current. This series is engineered to replace legacy Japanese parts such as the 2SK40 and 2SK105 while offering superior radiation tolerance.

Replacement Considerations

Public confirmed substitutes include 2SK40, 2SK105, SST202, 2N4868A, 2N4869A, 2N4221A, J231, J202, and VCR4N.