Transistors - JFETs

Part Number	Description / PDF	Quantity
MCH3914-7-TL-H Sanyo Semiconductor/ON Semiconductor	JFET N-CH 50MA 300MW SC70FL/MCPH	122869000
MMBFJ112 Sanyo Semiconductor/ON Semiconductor	JFET N-CH 35V 0.35W SOT-23	62716
J110RLRA	SMALL SIGNAL N-CHANNEL J-FET	18000
LSK389D TO-71 6L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	3953
2SK208-GR(TE85L,F) Toshiba Electronic Devices and Storage Corporation	JFET N-CH 50V SC59	2300
2SK208-R(TE85L,F) Toshiba Electronic Devices and Storage Corporation	JFET N-CH 50V S-MINI	0
J175-D26Z Sanyo Semiconductor/ON Semiconductor	JFET P-CH 30V 0.35W TO92-3	1004048000
PMBF4393,215 NXP Semiconductors	JFET N-CH 40V 250MW SOT23	0
NTE452 NTE Electronics, Inc.	JFET-N-CH UHF/VHF AMP	4
2SK508-T1B-A Renesas Electronics America	HIGH FREQUENCY N-CHANNEL JFET	1434210
LSK389A SOIC 8L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	4041
MMBF4117 Sanyo Semiconductor/ON Semiconductor	JFET N-CH 40V 0.225W SOT23	0
CMPF4416A TR Central Semiconductor	JFET N-CH 35V 10MA SOT23	0
PN4391 TRE Central Semiconductor	JFET N-CH 40V 0.625W TO92	0
MMBF4391LT1G	SMALL SIGNAL FIELD-EFFECT TRANSI	322863
2SK596S-C	SMALL SIGNAL FET	5831095
J111 Sanyo Semiconductor/ON Semiconductor	JFET N-CH 35V 625MW TO92-3	8695
BFR30LT1G	SMALL SIGNAL N-CHANNEL MOSFET	0
NTE2937 NTE Electronics, Inc.	JFET P-CHANNEL 30V TO-92	1953
J109 Sanyo Semiconductor/ON Semiconductor	JFET N-CH 25V 625MW TO92	0

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