SMPJ109TR

Overview

The SMPJ109TR is a surface-mount N-channel JFET in an SOT-23 package, part of the InterFET J108/J109 series. It features a -25V Gate to Source Breakdown Voltage (BVGSS), a Drain to Source Saturation Current (IDSS) range of 40mA to 80mA, and a Gate to Source Cutoff Voltage (VGS(off)) between -2V and -6V. The device exhibits low noise with a typical value of 1 nV/√Hz and high gain at 100mS typical. Static characteristics include a maximum Gate to Source Reverse Current (IGSS) of -3nA and a Drain Cutoff Current (ID) of 3nA. Dynamic parameters specify Drain to Source ON Resistance (RDS(ON)) of 8Ω to 12Ω, input capacitance (Cgs) of 15pF, and drain-gate capacitance (Cgd) of 15pF at 1MHz. Maximum ratings allow for continuous power dissipation of 360mW and an operating junction temperature from -55°C to 125°C.

Feature Summary

• Utilizes InterFET N0450S geometry for optimized performance.
• Designed for high gain and low noise switching applications.
• Available in Surface Mount Technology (SMT) packaging options.

Applications

• Chopper circuits
• Commutator systems
• Analog switches

Procurement Notes

Verify the specific binning requirements for IDSS and VGS(off) against your circuit design needs, as these parameters vary within the specified ranges. Confirm that the tape and reel quantity aligns with production volume requirements. Ensure ESD handling procedures are followed during assembly, as bulk products are shipped in standard ESD material. Cross-reference the mechanical layout data with your PCB footprint design to ensure proper soldering and thermal management.

Selection Notes

Select this component when low noise and high gain are critical for signal integrity in switching or commutator applications. Compare the IDSS and VGS(off) ranges against the J108 variant if higher saturation current is required. Consider the SOT-23 package constraints for thermal dissipation and board space. Verify compatibility with the intended supply voltage and signal levels to ensure operation within the specified breakdown and cutoff limits.

Part Context

The SMPJ109TR belongs to the J108/J109 family of N-channel JFETs manufactured by InterFET. This series is engineered using proprietary N0450S geometry to deliver superior noise and gain characteristics compared to standard silicon JFETs. The product line offers multiple packaging options, including through-hole TO-92, surface mount SOT-23, and bare die configurations, catering to diverse manufacturing and application requirements.

Replacement Considerations

The J108 is a direct pin-compatible alternative within the same series, offering different IDSS and VGS(off) characteristics. Verify electrical parameter alignment before substitution. No other cross-brand replacements are confirmed in the official documentation.

FAQ

What is the typical noise figure of the SMPJ109TR?

The typical noise figure is 1 nV/√Hz.

What is the maximum continuous power dissipation?

The maximum continuous power dissipation is 360 mW.

What is the operating junction temperature range?

The operating junction temperature range is -55°C to 125°C.