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Transistors - Bipolar (BJT) - RF

Image Part Number Description / PDF Quantity Rfq
2307

2307

Microsemi

RF TRANS NPN 42V 2.3GHZ 55BT

0
BFS17HTC

BFS17HTC

Zetex Semiconductors (Diodes Inc.)

RF TRANS NPN 15V 1.3GHZ SOT23-3

0
2SC3934G0L

2SC3934G0L

Panasonic

RF TRANS NPN 12V 4.5GHZ SMINI3

0
ZTX325STOA

ZTX325STOA

Zetex Semiconductors (Diodes Inc.)

RF TRANS NPN 15V 1.3GHZ E-LINE

0
NE68139-A

NE68139-A

CEL (California Eastern Laboratories)

RF TRANS NPN 10V 9GHZ SOT143

0
AT-41511-TR1

AT-41511-TR1

Broadcom

RF TRANS NPN 12V SOT143

0
NE68119-A

NE68119-A

CEL (California Eastern Laboratories)

RF TRANS NPN 10V 7GHZ SOT523

0
2SC3932GTL

2SC3932GTL

Panasonic

RF TRANS NPN 20V 1.6GHZ SMINI3

0
2SC5015-A

2SC5015-A

CEL (California Eastern Laboratories)

RF TRANS NPN 6V 12GHZ SOT343

0
NE851M03-A

NE851M03-A

CEL (California Eastern Laboratories)

RF TRANS NPN 5.5V 4.5GHZ SOT363

0
2SC39320SL

2SC39320SL

Panasonic

RF TRANS NPN 20V 1.6GHZ SMINI3

0
BFG520W,115

BFG520W,115

NXP Semiconductors

RF TRANS NPN 15V 9GHZ 4SO

0
MPSH10G

MPSH10G

Sanyo Semiconductor/ON Semiconductor

RF TRANS NPN 25V 650MHZ TO92-3

0
NE677M04-A

NE677M04-A

CEL (California Eastern Laboratories)

RF TRANS NPN 6V 15GHZ SOT343F

0
2SC5606-A

2SC5606-A

CEL (California Eastern Laboratories)

RF TRANS NPN 3.3V 21GHZ SOT523

0
DSC9G0200L

DSC9G0200L

Panasonic

RF TRANS NPN 20V 650MHZ SSMINI3

0
BF199_J35Z

BF199_J35Z

Sanyo Semiconductor/ON Semiconductor

RF TRANS NPN 25V 1.1GHZ TO92-3

0
BFP196WE6327HTSA1

BFP196WE6327HTSA1

IR (Infineon Technologies)

RF TRANS NPN 12V 7.5GHZ SOT343-4

0
BFG540W/X,115

BFG540W/X,115

NXP Semiconductors

RF TRANS NPN 15V 9GHZ CMPAK-4

0
BFR92AW,135

BFR92AW,135

NXP Semiconductors

RF TRANS NPN 15V 5GHZ SOT323-3

0

Transistors - Bipolar (BJT) - RF

1. Overview

Radio Frequency Bipolar Junction Transistors (RF BJTs) are three-layer semiconductor devices optimized for amplification and switching in high-frequency applications (typically >100 MHz). These transistors maintain stable performance in microwave and ultra-high frequency (UHF) ranges, characterized by high current gain-bandwidth product (fT), low noise figures, and fast switching capabilities. Their importance in modern technology spans wireless communication infrastructure, radar systems, and RF test equipment, enabling efficient signal transmission and reception in 5G networks, satellite communications, and IoT devices.

2. Main Types & Functional Classification

TypeFunctional FeaturesApplication Examples
NPN RF BJTHigh electron mobility, optimized for low-noise amplification5G base station LNAs, GPS receivers
PNP RF BJTComplementary design for power amplificationRF power modules, automotive radar
RF Darlington PairHigh (current gain), cascaded amplificationAntenna drivers, industrial RF heaters
Heterojunction Bipolar Transistor (HBT)Compound semiconductor materials (SiGe/GaAs), ultra-high fTOptical communication transceivers, mmWave systems

3. Structure & Composition

Typical RF BJT structure includes:

  • Material: Silicon (Si), Silicon-Germanium (SiGe), Gallium Arsenide (GaAs)
  • Layer Architecture: Emitter (high doping), Base (thin layer), Collector (graded doping)
  • Package Types: Surface-mount (SOT-89, SOT-343), Through-hole (TO-18, TO-92)
  • Metallization: Gold/aluminum contacts for reduced parasitic resistance

Advanced designs incorporate air-bridge structures to minimize parasitic capacitance and epitaxial layers for improved frequency response.

4. Key Technical Parameters

ParameterDescriptionTypical Range
fT (Transition Frequency)Current gain cutoff frequency1 GHz - 100 GHz
GUM (Max. Available Gain)Power gain at optimal impedance10 dB - 30 dB
Pout (Output Power)RMS power capability0.1 W - 500 W
NF (Noise Figure)Signal-to-noise degradation0.3 dB - 5 dB
VCE0 (Breakdown Voltage)Collector-emitter withstand voltage5 V - 80 V
(Junction Temperature)Thermal stability limit150 C - 200 C

5. Application Fields

  • Telecommunications: 5G massive MIMO amplifiers, fiber optic transceivers
  • Defense: Phased array radar systems, electronic warfare jammers
  • Test & Measurement: RF signal generators, spectrum analyzers
  • Consumer Electronics: Bluetooth LE modules, Wi-Fi 6E front-ends
  • Industrial: Plasma generators, RFID readers

6. Leading Manufacturers & Products

ManufacturerRepresentative ProductKey Specifications
Infineon TechnologiesBFP740FfT=50 GHz, NF=0.8 dB, Pout=18 dBm
STMicroelectronicsSTAG21412.7 GHz dual-stage amplifier, 32 dB gain
Skyworks SolutionsASK240110.05-6 GHz, 50 W GaAs power transistor
ON SemiconductorMRF151G125 W, 880 MHz, 40% efficiency

7. Selection Guidelines

Key considerations:

  1. Match fT to application frequency with 20% margin
  2. Verify load-line requirements for power applications
  3. Select appropriate package for thermal dissipation (e.g., TO-220 for >50 W)
  4. Derate VCE0 by 30% in high-temperature environments
  5. Consider integrated solutions (RFICs) for complex impedance matching

8. Industry Trends

Future development directions:

  • Transition to SiGe BiCMOS technology for 100+ GHz applications
  • Integration with GaN-on-SiC substrates for hybrid power amplifiers
  • Development of 5G NR direct-conversion transmitters using HBT arrays
  • Advancements in wafer-level packaging (WLP) for mmWave 5G devices
  • Adoption of AI-driven parameter optimization in production testing
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