Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - RF

Part Number	Description / PDF	Quantity
2SC5066-O,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ SSM	29950
2SC5087R(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 8GHZ SMQ	5418
2SC5087YTE85LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ SMQ	1057
2SC5085-Y(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ USM	0
2SC5085-O(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ USM	2181
MT4S300U(TE85L,O,F Toshiba Electronic Devices and Storage Corporation	X34 PB-F RADIO-FREQUENCY SIGE HE	8288
MT3S111P(TE12L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 6V 8GHZ PW-MINI	7857
2SC5108-Y,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 10V 6GHZ SSM	0
2SC4915-O,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 30V 550MHZ SSM	2463
MT3S113TU,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 5.3V 11.2GHZ UFM	5800
2SC4915-Y,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 30V 550MHZ SSM	31
2SC5084-O(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ SMINI	0
2SC5065-O(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ USM	0
2SC5065-Y(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ USM	4556
MT3S20TU(TE85L) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ UFM	2871
MT3S16U(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 5V 4GHZ USM	7679
HN3C10FUTE85LF Toshiba Electronic Devices and Storage Corporation	RF TRANS 2 NPN 12V 7GHZ US6	111
MT3S113(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 5.3V 12.5GHZ SMINI	5819
2SC5086-Y,LF Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 12V 7GHZ SSM	0
2SC5095-R(TE85L,F) Toshiba Electronic Devices and Storage Corporation	RF TRANS NPN 10V 10GHZ SC70	5353

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