Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - RF

Part Number	Description / PDF	Quantity
2SC4915-O,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 30V 550MHZ SSM	2463
2N2857 Sanyo Semiconductor/ON Semiconductor	DIE RF TRANS NPN 15V	0
UPA800T-T1 CEL (California Eastern Laboratories)	RF TRANS 2 NPN 10V 8GHZ 6SO	6
MX0912B351Y,114 Ampleon	RF TRANSISTOR	131
MT3S113TU,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 5.3V 11.2GHZ UFM	5800
BFP842ESDH6327XTSA1 IR (Infineon Technologies)	RF TRANS NPN 3.7V 60GHZ SOT343	5635
MMBTH10	RF SMALL SIGNAL TRANSISTOR	12000
BGR420H6327 IR (Infineon Technologies)	BIASED LOW NOISE RF TRANSISTOR	222000
MZ0912B50Y,114 Ampleon	RF TRANSISTOR	1
PH2729-25M Metelics (MACOM Technology Solutions)	RF TRANS NPN 60V	3
2SC5226A-5-TL-E Sanyo Semiconductor/ON Semiconductor	RF TRANS NPN 10V 7GHZ 3MCP	118000
BFP196WH6740 IR (Infineon Technologies)	RF TRANSISTOR, L BAND, NPN	99000
NTE55 NTE Electronics, Inc.	RF TRANS PNP 150V 30MHZ TO220	208
BFP183E7764HTSA1 IR (Infineon Technologies)	RF TRANS NPN 12V 8GHZ SOT143-4	7330
KSC1674CYBU	RF SMALL SIGNAL TRANSISTOR	30990
2SC4808G0L Panasonic	RF TRANS NPN 10V 6GHZ SSMINI3-F3	5980
BFR843EL3E6327XTSA1 IR (Infineon Technologies)	RF TRANS NPN 2.6V TSLP-3-10	15000
2SC4915-Y,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 30V 550MHZ SSM	31
BFR380TE6327 IR (Infineon Technologies)	RF BIPOLAR TRANSISTOR	162000
2SC5754-T2-A Renesas Electronics America	RF 0.5A, NPN	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