Transistors - Bipolar (BJT) - Single, Pre-Biased

Image Part Number Description / PDF Quantity Rfq
SMMUN2211LT1G

SMMUN2211LT1G

Sanyo Semiconductor/ON Semiconductor

TRANS PREBIAS NPN 50 SOT23-3

55754

DTD114GKT146

DTD114GKT146

ROHM Semiconductor

TRANS PREBIAS NPN 200MW SMT3

1587

DRA5115E0L

DRA5115E0L

Panasonic

TRANS PREBIAS PNP 150MW SMINI3

3000

BCR198E6327

BCR198E6327

IR (Infineon Technologies)

BIPOLAR DIGITAL TRANSISTOR

147000

BCR108WH6327XTSA1

BCR108WH6327XTSA1

IR (Infineon Technologies)

BIPOLAR DIGITAL TRANSISTOR

105000

MUN2214T1

MUN2214T1

TRANS PREBIAS NPN 338MW SC59

117000

DTC114TM3T5G

DTC114TM3T5G

Sanyo Semiconductor/ON Semiconductor

TRANS PREBIAS NPN 50V SOT723

327480000

PDTA123TT,235

PDTA123TT,235

Nexperia

NOW NEXPERIA PDTA123TT - SMALL S

9840

DTA113ZUAT106

DTA113ZUAT106

ROHM Semiconductor

TRANS PREBIAS PNP 200MW UMT3

0

DTA144EM3T5G

DTA144EM3T5G

Sanyo Semiconductor/ON Semiconductor

TRANS PREBIAS PNP 50V SOT723

2147483647

DTC124XM3T5G

DTC124XM3T5G

SMALL SIGNAL BIPOLAR TRANSISTOR,

387342

DDTD122TC-7-F

DDTD122TC-7-F

Zetex Semiconductors (Diodes Inc.)

TRANS PREBIAS NPN 200MW SOT23-3

85588

FJY4001R

FJY4001R

SMALL SIGNAL BIPOLAR TRANSISTOR

15000

UNR51ANG0L

UNR51ANG0L

Panasonic

TRANS PREBIAS PNP 150MW SMINI3

5610

NSVDTA113EM3T5G

NSVDTA113EM3T5G

Sanyo Semiconductor/ON Semiconductor

TRANS PNP 50V 0.1A SOT723

0

RN2405,LF

RN2405,LF

Toshiba Electronic Devices and Storage Corporation

TRANS PREBIAS PNP 50V 0.1A SMINI

0

DTA114YU3HZGT106

DTA114YU3HZGT106

ROHM Semiconductor

DTA114YU3HZG IS AN DIGITAL TRANS

2558

PDTC123YM,315

PDTC123YM,315

Nexperia

NOW NEXPERIA PDTC123YM - SMALL S

158000

DTC144TET1G

DTC144TET1G

Sanyo Semiconductor/ON Semiconductor

TRANS PREBIAS NPN 50V 100MA SC75

138000

DTC043ZEBTL

DTC043ZEBTL

ROHM Semiconductor

TRANS PREBIAS NPN 50V EMT3F

0

Transistors - Bipolar (BJT) - Single, Pre-Biased

1. Overview

Pre-biased bipolar junction transistors (BJTs) are discrete semiconductor devices with integrated biasing resistors, designed to simplify circuit design and improve operational stability. Unlike standard BJTs requiring external biasing components, pre-biased BJTs incorporate internal resistors to set the base-emitter voltage and collector current. These devices are critical in modern electronics for applications demanding compact design, consistent performance, and reduced component count. Their ability to maintain stable operation under varying temperature and voltage conditions makes them essential in consumer electronics, industrial automation, and automotive systems.

2. Main Types and Functional Classification

TypeFunctional FeaturesApplication Examples
NPN Pre-Biased BJTPositive bias resistor network, low-side switchingLogic-level switching, LED drivers
PNP Pre-Biased BJTNegative bias resistor network, high-side switchingPower supply control, relay drivers
Digital TransistorIntegrated resistors with ESD protectionDigital logic circuits, portable devices

3. Structure and Composition

Pre-biased BJTs consist of a silicon semiconductor die with three doped regions (emitter, base, collector) forming two p-n junctions. The key structural elements include: - Monolithic Resistor Network: Thin-film or diffused resistors embedded in the die for fixed biasing - Metal Contacts: Aluminum or copper layers for external connections - Encapsulation: Plastic or ceramic packaging with standard pinouts (e.g., SOT-23, TO-92) - Passivation Layer: Silicon dioxide/nitride coating to prevent surface contamination

4. Key Technical Specifications

ParameterDescriptionImportance
Current Gain (hFE)Ratio of collector to base currentDetermines amplification capability
Max Collector Voltage (VCEO)Max voltage across collector-emitterDefines operating voltage range
Transition Frequency (fT)Frequency response limitCritical for RF and switching applications
Power Dissipation (Ptot)Max thermal power handlingDictates thermal management needs
Built-in Resistor Ratio (R1/R2)Internal resistor division ratioControls bias point stability

5. Application Areas

Main industries and typical equipment: - Consumer Electronics: Mobile phone chargers, wearable devices - Industrial Automation: PLC modules, motor drivers - Automotive: Sensor interfaces, LED lighting systems - Telecommunications: Base station power amplifiers - Power Management: DC-DC converter switches

6. Leading Manufacturers and Products

ManufacturerKey ProductsFeatures
ON SemiconductorMMBT3904L200mA NPN transistor with 47k bias resistors
Toshiba2SB1958PNP device with built-in 10k /4.7k resistor network
STMicroelectronicsSM6T120NAutomotive-grade digital transistor with ESD protection

7. Selection Guidelines

Key considerations: - Match hFE with required amplification/saturation characteristics - Confirm VCEO rating exceeds circuit voltage requirements - Select resistor ratios for desired bias point (e.g., R1=10k , R2=22k for mid-range bias) - Prioritize thermal performance in high-power applications - Consider package type (SMD vs. through-hole) for PCB constraints

8. Industry Trends

Emerging trends include: - Miniaturization: Development of 0.4mm pitch WLCSP packages - Integrated protection: ESD/clamp diodes in standard designs - High-frequency variants: fT > 5GHz for 5G infrastructure - Automotive qualification: Increased demand for AEC-Q101 certified devices - Green manufacturing: Lead-free packaging and low-toxicity materials

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