Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - RF

Part Number	Description / PDF	Quantity
EC4H09C-TL-H	TRANSISTOR	37000
BFR93AR,215 NXP Semiconductors	RF SMALL SIGNAL TRANSISTOR	0
BFU550XRVL NXP Semiconductors	RF TRANS NPN 12V 11GHZ SOT143R	0
SS9018HBU	RF 0.05A, VERY HIGH FREQUENCY BA	15000
MRF1004MB Metelics (MACOM Technology Solutions)	TRANS NPN 4W 960MHZ-1215MHZ	0
DSC5G0200L Panasonic	RF TRANS NPN 20V 650MHZ SMINI3	3643
KSC1674OTA	RF SMALL SIGNAL TRANSISTOR	84000
MMBTH24	RF 0.05A, VERY HIGH FREQUENCY BA	19751
BFR193WE6327 IR (Infineon Technologies)	HIGH LINEARITY TRANSISTOR	3000
BFU520AVL NXP Semiconductors	RF TRANS NPN 12V 10GHZ TO236AB	0
BFU730F,115 NXP Semiconductors	RF TRANS NPN 2.8V 55GHZ 4DFP	35017
2SC4713KT146R ROHM Semiconductor	RF TRANS NPN 6V 800MHZ SMT3	0
KSC1730YBU	RF SMALL SIGNAL TRANSISTOR	584790
CA3246M	HIGH FREQUENCIES NPN TRANSISTOR	514
HFA3127RZ Intersil (Renesas Electronics America)	RF TRANS 5 NPN 12V 8GHZ 16QFN	129
BFP193E6327	BFP193 - HIGH LINEARITY SI- AND	14115
MRF587 Metelics (MACOM Technology Solutions)	TRANS RF NPN 17A 200MA 244A-01	0
PH1090-550S Metelics (MACOM Technology Solutions)	RF TRANS NPN 80V	40
BFP640ESDH6327XTSA1 IR (Infineon Technologies)	RF TRANS NPN 4.7V 46GHZ SOT343	5580
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