Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - RF

Part Number	Description / PDF	Quantity
2SC393700L Panasonic	RF TRANS NPN 10V 6GHZ SMINI3-G1	5950
2SC27780CL Panasonic	RF TRANS NPN 20V 230MHZ MINI3-G1	5860
BFS481H6327XTSA1 IR (Infineon Technologies)	RF TRANS 2 NPN 12V 8GHZ SOT363-6	8514
ON5089,115 NXP Semiconductors	RF TRANSPONDER SOT343F	5910
BFU520R NXP Semiconductors	RF TRANS NPN 12V 10.5GHZ SOT143B	2943
BFP181E7764 IR (Infineon Technologies)	RF TRANSISTOR, L BAND, NPN	2900
NTE346 NTE Electronics, Inc.	RF TRANS NPN 20V 500MHZ TO39	60
MMBTH10-4LT1G Sanyo Semiconductor/ON Semiconductor	RF TRANS NPN 25V 800MHZ SOT23-3	7165
BFR193FH6327XTSA1 IR (Infineon Technologies)	RF TRANS NPN 12V 8GHZ TSFP-3	710
BFU760F,115 NXP Semiconductors	RF TRANS NPN 2.8V 45GHZ 4DFP	7435
MSC2295-CT1G	RF SMALL SIGNAL TRANSISTOR	27000
BFS17WE6327 IR (Infineon Technologies)	RF BIPOLAR TRANSISTOR	3000
HFA3128B Intersil (Renesas Electronics America)	RF SMALL SIGNAL TRANSISTOR	5745
2SC4227-T1-A Renesas Electronics America	RF TRANSISTOR FOR HIGH FREQUENCY	102000
BFU530AVL NXP Semiconductors	RF TRANS NPN 12V 11GHZ TO236AB	0
BFR740L3RHE6327XTSA1 IR (Infineon Technologies)	RF TRANS NPN 4.7V 42GHZ TSLP-3	8124
BFP450H6327XTSA1 IR (Infineon Technologies)	RF TRANS NPN 5V 24GHZ SOT343-4	5862
HFA3127BZ Intersil (Renesas Electronics America)	RF TRANS 5 NPN 12V 8GHZ 16SOIC	0
MPSH10	RF SMALL SIGNAL TRANSISTOR	31257
MRF16006 Metelics (MACOM Technology Solutions)	TRANS RF NPN 28V 6W 395C-01	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 (f_T), 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

Type	Functional Features	Application Examples
NPN RF BJT	High electron mobility, optimized for low-noise amplification	5G base station LNAs, GPS receivers
PNP RF BJT	Complementary design for power amplification	RF power modules, automotive radar
RF Darlington Pair	High (current gain), cascaded amplification	Antenna drivers, industrial RF heaters
Heterojunction Bipolar Transistor (HBT)	Compound semiconductor materials (SiGe/GaAs), ultra-high f_T	Optical 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

Parameter	Description	Typical Range
f_T (Transition Frequency)	Current gain cutoff frequency	1 GHz - 100 GHz
G_UM (Max. Available Gain)	Power gain at optimal impedance	10 dB - 30 dB
P_out (Output Power)	RMS power capability	0.1 W - 500 W
NF (Noise Figure)	Signal-to-noise degradation	0.3 dB - 5 dB
V_CE0 (Breakdown Voltage)	Collector-emitter withstand voltage	5 V - 80 V
(Junction Temperature)	Thermal stability limit	150 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

Manufacturer	Representative Product	Key Specifications
Infineon Technologies	BFP740F	f_T=50 GHz, NF=0.8 dB, P_out=18 dBm
STMicroelectronics	STAG2141	2.7 GHz dual-stage amplifier, 32 dB gain
Skyworks Solutions	ASK24011	0.05-6 GHz, 50 W GaAs power transistor
ON Semiconductor	MRF151G	125 W, 880 MHz, 40% efficiency

7. Selection Guidelines

Key considerations:

Match f_T to application frequency with 20% margin
Verify load-line requirements for power applications
Select appropriate package for thermal dissipation (e.g., TO-220 for >50 W)
Derate V_CE0 by 30% in high-temperature environments
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