Transistors - JFETs

Part Number	Description / PDF	Quantity
LSK389A TO-71 6L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	6952
LSK389B TO-71 6L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	4919
LS320 TO-92 3L Linear Integrated Systems, Inc.	BIFET AMPLIFIER - HIGH INPUT Z A	1005
LS26VNS DFN 8L Linear Integrated Systems, Inc.	SINGLE N-CHANNEL JFET, VOLTAGE C	14180
LS5301 TO-18 3L Linear Integrated Systems, Inc.	HIGH IMPEDANCE, SINGLE, N-CHANNE	100
LSK389D SOIC 8L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	10725
4392DFN 8L Linear Integrated Systems, Inc.	LOW NOISE, N-CHANNEL JFET SWITCH	19477
LSK389B SOIC 8L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	20494
176DFN 8L Linear Integrated Systems, Inc.	P-CHANNEL, SINGLE, JFET SWITCH	100
LS320 DIE Linear Integrated Systems, Inc.	BIFET AMPLIFIER - HIGH INPUT Z A	400
4391DFN 8L Linear Integrated Systems, Inc.	LOW NOISE, N-CHANNEL JFET SWITCH	12285
LSK389C SOIC 8L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	24433
175DFN 8L Linear Integrated Systems, Inc.	P-CHANNEL, SINGLE, JFET SWITCH	1958
LS320 SOT-23 3L Linear Integrated Systems, Inc.	BIFET AMPLIFIER - HIGH INPUT Z A	14944
LSK389D TO-71 6L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	3953
LSK389A SOIC 8L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	4041
LS26VPS DFN 8L Linear Integrated Systems, Inc.	SINGLE P-CHANNEL JFET, VOLTAGE C	12896
4393DFN 8L Linear Integrated Systems, Inc.	LOW NOISE, N-CHANNEL JFET SWITCH	2785
LS320 TO-72 4L Linear Integrated Systems, Inc.	BIFET AMPLIFIER - HIGH INPUT Z A	5
PF5301 TO-92 3L Linear Integrated Systems, Inc.	HIGH IMPEDANCE, SINGLE, N-CHANNE	39259

Transistors - JFETs

1. Overview

Junction Field-Effect Transistors (JFETs) are three-terminal voltage-controlled semiconductor devices that regulate current flow through a conductive channel. As the first type of field-effect transistor, JFETs are characterized by high input impedance, low noise, and excellent analog signal handling capabilities. They play critical roles in modern electronics for signal amplification, switching, and impedance matching applications.

2. Main Types and Functional Classification

Type	Functional Features	Application Examples
N-channel JFET	Higher electron mobility, faster operation	Audio amplifiers, RF mixers
P-channel JFET	Complementary to N-channel, lower speed	Power switching, analog switches
Dual-gate JFET	Two control gates for improved linearity	TV tuners, communication systems
High-frequency JFET	Optimized for GHz-range performance	RF amplifiers, microwave circuits

3. Structure and Composition

JFETs consist of a semiconductor channel (typically silicon or GaAs) with source and drain contacts at each end. A reverse-biased p-n junction gate controls the channel width. Key structural elements include: - Channel: Determines current capacity and transconductance - Gate: Forms depletion region to modulate channel conductivity - Metallization layers: Provide low-resistance contacts - Passivation layer: Protects device surface from contamination

4. Key Technical Specifications

Parameter	Description	Importance
V_GS(off)	Gate-source cutoff voltage	Determines operating voltage range
I_DSS	Saturation drain current	Defines maximum current capability
g_m	Transconductance	Measures amplification efficiency
R_DS(on)	On-state resistance	Impacts power dissipation
f_T	Transition frequency	Limits high-frequency performance

5. Application Fields

Major industries utilizing JFETs include: - Audio equipment: Guitar amplifiers, microphone preamps - Test & measurement: Oscilloscopes, signal analyzers - Industrial control: Sensor interfaces, process control - Medical devices: ECG machines, diagnostic equipment - Communication systems: RF front-ends, satellite receivers

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
TI (Texas Instruments)	J111	General-purpose N-channel JFET
ON Semiconductor	2N5457	High-voltage switching applications
Infineon Technologies	BF862	Low-noise RF amplifier JFET
STMicroelectronics	STJ105	Power JFET for industrial systems

7. Selection Guidelines

Consider the following factors when selecting JFETs: - Application type: Audio (low noise), switching (high I_DSS), or RF (high f_T) - Operating conditions: Temperature range, voltage requirements - Package type: Through-hole for prototyping vs. surface-mount for mass production - Cost vs performance: Balance between specifications and budget constraints

8. Industry Trends

Emerging trends shaping JFET development include: - Development of wide-bandgap JFETs using SiC/GaN for high-power applications - Integration with CMOS technology for mixed-signal systems - Miniaturization for portable electronics - Enhanced radiation-hardened variants for aerospace applications - Growing adoption in bio-sensing and IoT edge devices