Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
2SD600KF	BIP NPN 1A 100V	48380
BCR555 IR (Infineon Technologies)	BIPOLAR DIGITAL TRANSISTOR	305000
BCX56-16 Diotec Semiconductor	BJT SOT-89 80V 1000MA	0
BC857CWT1G Sanyo Semiconductor/ON Semiconductor	TRANS PNP 45V 100MA SC70-3	5165
KSD2012GTU Sanyo Semiconductor/ON Semiconductor	TRANS NPN 60V 3A TO-220F	1630
BD14010S	TRANS PNP 80V 1.5A TO126-3	2748
NTE241 NTE Electronics, Inc.	TRANS NPN 80V 4A TO220	157
BSP50E6327 IR (Infineon Technologies)	SMALL SIGNAL BIPOLAR TRANSISTOR	1000
KSP44BU Sanyo Semiconductor/ON Semiconductor	TRANS NPN 400V 300MA TO92-3	1739
BCP56-16T3G Sanyo Semiconductor/ON Semiconductor	TRANS NPN 80V 1A SOT-223	13679
ZXT13N50DE6TA Zetex Semiconductors (Diodes Inc.)	TRANS NPN 50V 4A SOT23-6	46332
JANTX2N3440L Roving Networks / Microchip Technology	TRANS NPN 250V 1A	0
2SC603600L Panasonic	TRANS NPN 12V 0.5A SSSMINI-3	9800
TIP142T STMicroelectronics	TRANS NPN DARL 100V 10A TO-220	1205
PVR100AZ-B12V,115 NXP Semiconductors	TRANS NPN 45V 100MA SOT223	3951
2SCR586D3TL1 ROHM Semiconductor	POWER TRANSISTOR WITH LOW VCE(SA	1065
BC857BFA-7B Zetex Semiconductors (Diodes Inc.)	TRANS PNP 45V 0.1A X2-DFN0806-3	1194
2N6284 NTE Electronics, Inc.	TRANS NPN 100V 20A TO204	32
FJX945GTF-ON	0.15A, 50V, NPN	6000
PMMT591A,235 Nexperia	TRANS PNP 40V 1A TO236AB	702

Transistors - Bipolar (BJT) - Single

1. Overview

Bipolar Junction Transistors (BJTs) are three-terminal semiconductor devices that use both electron and hole charge carriers. They form the foundation of analog electronics through their ability to amplify signals and control current flow. BJTs remain critical in modern electronics for applications ranging from audio amplifiers to power management circuits, offering superior linearity and robustness in switching operations.

2. Main Types & Functional Classification

Type	Functional Characteristics	Application Examples
NPN Transistor	Majority carriers: electrons. Requires positive base current for conduction.	Low-noise amplifiers, digital logic circuits
PNP Transistor	Majority carriers: holes. Conducts with negative base current.	Power supply circuits, motor controllers
High-Frequency BJT	Optimized for RF/microwave signal amplification (f_T > 100 MHz)	Wireless communication systems, radar
Power BJT	High current/voltage ratings (I_C > 1A, V_CE > 50V)	Switch-mode power supplies, motor drives

3. Structure & Composition

BJTs consist of three doped semiconductor regions forming two p-n junctions:

Emitter: Heavily doped region emitting charge carriers
Base: Thin, lightly doped middle region controlling carrier flow
Collector: Moderately doped region collecting carriers

Manufactured using silicon (common) or germanium (historic) with planar processing technology. The structure forms either NPN (n-type emitter/base/collector) or PNP configuration, with metal contacts for external connections.

4. Key Technical Specifications

Parameter	Description	Importance
Current Gain (h_FE)	Ratio of collector to base current (10-1000)	Determines amplification capability
Transition Frequency (f_T)	Frequency at which current gain drops to 1	Limits high-frequency performance
Max Collector Current (I_Cmax)	Maximum allowable continuous collector current	Defines power handling capability
Breakdown Voltage (V_CEO)	Max voltage between collector and emitter	Prevents device failure under stress
Saturation Voltage (V_CEsat)	Voltage drop in fully conducting state	Affects power efficiency in switching

5. Application Areas

Consumer Electronics: Audio amplifiers, LED drivers
Automotive: Engine control units, electric vehicle inverters
Industrial: PLCs, motor controllers
Telecommunications: RF power amplifiers, fiber optic transceivers
Aerospace: Avionics systems, satellite transponders

6. Leading Manufacturers & Products

Manufacturer	Product Series	Key Specifications	Typical Use
ON Semiconductor	2N3904	hFE: 100-300, fT: 300 MHz	General-purpose switching
Infineon	BC547	VCEO: 50V, ICmax: 100mA	Analog signal amplification
STMicroelectronics	2SD2656	ICmax: 15A, VCEO: 80V	Power inverter applications
Diodes Inc.	BFR93A	fT: 10 GHz, Noise Figure: 2dB	High-frequency front-end amplifiers

7. Selection Guidelines

Determine operating frequency: Select fT > 3 target frequency
Power requirements: Ensure Icmax and VCEO exceed circuit requirements by 20%
Thermal considerations: Calculate power dissipation (P=V_CE I_C)
Package type: TO-92 for low power, TO-220 for high-power applications
Environmental factors: Consider temperature ratings for industrial/military use

8. Industry Trends

Future developments include:

High-frequency BJTs operating beyond 100 GHz for 6G communication
Integrated BJT-MOSFET hybrid devices (BiCMOS) for mixed-signal applications
Wide-bandgap materials (SiC/GaN) for higher power density
Miniaturization through chip-scale packaging
Improved thermal management solutions for automotive applications