Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - RF

Part Number	Description / PDF	Quantity
2SC4562GRL Panasonic	RF TRANS NPN 50V 250MHZ SMINI3	5820
BFG97,115 NXP Semiconductors	RF SMALL SIGNAL BIPOLAR TRANSIST	44000
BFR35APE6327HTSA1 IR (Infineon Technologies)	RF TRANS NPN 15V 5GHZ SOT23-3	0
BFP450 IR (Infineon Technologies)	RF SMALL SIGNAL BIPOLAR TRANSIST	130871
BFR360FH6327XTSA1 IR (Infineon Technologies)	RF TRANS NPN 9V 14GHZ TSFP-3	40519
MMBTH81 Sanyo Semiconductor/ON Semiconductor	RF TRANS PNP 20V 600MHZ SOT23-3	54776
2SC5347AF-TD-E Sanyo Semiconductor/ON Semiconductor	RF TRANS NPN 12V 4.7GHZ PCP	746
BF240	GENERAL PURPOSE NPN TRANSISTOR	6300
2SC5536A-TL-H Sanyo Semiconductor/ON Semiconductor	RF TRANS NPN 12V 1.7GHZ 3SSFP	2147483647
MRF426 Metelics (MACOM Technology Solutions)	TRANS RF NPN 35V 3A 211-07	0
2N5179 PBFREE Central Semiconductor	RF TRANS NPN 12V 2GHZ TO72	69
2SC39310CL Panasonic	RF TRANS NPN 20V 650MHZ SMINI3	191
BFU520VL NXP Semiconductors	RF TRANS NPN 12V 10.5GHZ SOT143B	0
BFP193E6327HTSA1 IR (Infineon Technologies)	RF TRANS NPN 12V 8GHZ SOT143-4	8448
BGR405H6327XTSA1 IR (Infineon Technologies)	RF SMALL SIGNAL TRANSISTOR	939000
HFA3102BZ96 Intersil (Renesas Electronics America)	RF TRANS 6 NPN 12V 10GHZ 14SOIC	1162
15GN03CA-TB-E Sanyo Semiconductor/ON Semiconductor	RF TRANS NPN 10V 1.5GHZ 3CP	3716
MT4S300U(TE85L,O,F Toshiba Electronic Devices and Storage Corporation	X34 PB-F RADIO-FREQUENCY SIGE HE	8288
BFR183E6327	BFR183 - LOW-NOISE SI TRANSISTOR	31800
BFR35AP IR (Infineon Technologies)	BFR35 - LOW-NOISE SI TRANSISTORS	3001

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