Transistors - JFETs

Part Number	Description / PDF	Quantity
2SK880GRTE85LF Toshiba Electronic Devices and Storage Corporation	JFET N-CH 50V 0.1W USM	2306
2N4221A NTE Electronics, Inc.	T-JFET N CHANNEL	40
MMBF4393LT3G Sanyo Semiconductor/ON Semiconductor	JFET N-CH 30V 0.225W SOT23	10000
J111RL1G	SMALL SIGNAL N-CHANNEL MOSFET	30000
BSR58 Sanyo Semiconductor/ON Semiconductor	JFET N-CH 40V 0.25W SOT-23	9433
LSK389B TO-71 6L Linear Integrated Systems, Inc.	LOW NOISE, MONOLITHIC DUAL, N-CH	4919
MMBF5103 Sanyo Semiconductor/ON Semiconductor	JFET N-CH 40V 0.35W SOT-23	49090000
2SK275100L Panasonic	JFET N-CH 10MA 200MW MINI-3	61
MMBF4393LT1	JFET N-CH 30V 0.225W SOT23	2063
J111-D74Z Sanyo Semiconductor/ON Semiconductor	JFET N-CH 35V 625MW TO92-3	3396
2N5115 Roving Networks / Microchip Technology	P CHANNEL JFET	0
NTE468 NTE Electronics, Inc.	JFET-N-CHANNEL SWITCH TO-92	268
J107	SMALL SIGNAL FIELD-EFFECT TRANSI	12681
2N5638RLRA	SMALL SIGNAL FET	4000
J112G	SMALL SIGNAL N-CHANNEL MOSFET	2263
J176	SMALL SIGNAL P-CHANNEL MOSFET	2000
LS320 TO-92 3L Linear Integrated Systems, Inc.	BIFET AMPLIFIER - HIGH INPUT Z A	1005
MMBF4392LT1	SMALL SIGNAL N-CHANNEL MOSFET	33000
JANTX2N4859 Microsemi	JFET N-CH 30V 360MW TO-18	1209
NTE133 NTE Electronics, Inc.	FET-AF AMP SWITCH	121

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