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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Bipolar RF Transistors

NXP Semiconductors BFG520,235

Name: BFG520,235
Brand: NXP Semiconductors
SKU: BFG520,235
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BFG520,235

Manufacturer:: NXP Semiconductors

Category:: Bipolar RF Transistors

Package:: TO-253-4, TO-253AA

Datasheet:: BFG520,235.pdf

Description:: RF TRANS NPN 15V 9GHZ SOT143B

Quantity:: RFQ Add To RFQ list

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Inventory:9,855

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Product details

Overview

BFG520,235 from NXP Semiconductors is an NPN silicon planar epitaxial RF transistor in SOT143B package, designed for GHz-range front-end amplification with 9 GHz transition frequency (f_T), 1.1 dB minimum noise figure at 900 MHz, and 19 dB maximum unilateral power gain at 900 MHz. It serves in analog/digital cellular telephones, DECT cordless phones, satellite TV tuners, and fiber-optic repeater amplifiers.

For engineers reviewing the BFG520,235 datasheet, BFG520,235 pinout, BFG520,235 application, or BFG520,235 equivalent, this page delivers verified pin configuration, real-world RF performance metrics, thermal derating behavior, noise circle data, and validated alternative transistors for high-frequency LNA and driver stage design.

Technical Context

The BFG520,235 operates as a common-emitter broadband amplifier with dual-emitter topology optimized for impedance matching in 50 Ω systems. Its gold metallization ensures reliability under RF stress, while its f_T = 9 GHz and G_UM = 19 dB at 900 MHz support stable gain up to 2 GHz.

Thermal resistance R_{th j–s} = 290 K/W is referenced to the collector soldering point (T_s ≤ 88 °C), and noise performance is specified at Γ_s = Γ_opt, enabling low-noise amplifier design with minimal external tuning components.

Key Specifications

Parameter	Value and Actual Design Meaning
f_T	9 GHz - enables stable amplification up to 2 GHz with usable gain margin
F_min	1.1 dB at 900 MHz - sets fundamental limit for LNA noise floor in cellular bands
G_UM	19 dB at 900 MHz - provides high isolation and unconditional stability in matched designs
P_tot	300 mW up to T_s = 88 °C - defines maximum DC + RF power dissipation before thermal derating
V_CEO	15 V - determines maximum supply voltage for common-emitter biasing without breakdown
C_re	0.3 pF - limits Miller effect and supports wideband input matching
I_C max	70 mA - sets upper DC bias current limit for linear operation and thermal safety

Pinout & Package

Package: SOT143B - 4-pin plastic surface-mount package with collector tab for thermal conduction; dimensions per IEC/JEDEC outline (D = 2.8–3.0 mm, E = 1.2–1.4 mm, A = 0.9–1.1 mm).

Pin/Terminal	Circuit Role	Design Meaning
1	Collector	Main RF output node; connected to heatsink tab for thermal management
2	Base	RF input control terminal; requires DC bias and AC coupling for broadband operation
3	Emiter	Primary emitter connection; used for DC return and RF ground reference
4	Emiter	Dual-emitter configuration enables improved thermal symmetry and reduced parasitic inductance

Key Features

Feature	Design Value
Gold metallization	Ensures long-term bond-wire integrity and interconnect reliability under RF thermal cycling
Dual-emitter structure	Reduces effective emitter inductance and improves high-frequency current sharing
Low C_re (0.3 pF)	Minimizes feedback path capacitance, supporting unconditional stability up to 2 GHz
Γ_opt noise matching	Enables optimal noise figure with standard 50 Ω source impedance via simple matching network
High h_FE (60–250)	Supports robust DC bias stability across process and temperature variations

Applications

Cellular Phone Front-End	Satellite TV Tuner LNA
Use Scenario: Low-noise amplification of 800–1000 MHz receive signals in GSM/EDGE handsets. IC Role / Device Role / Timing Role: First-stage LNA in RF receiver chain, operating at I_C = 5 mA, V_CE = 6 V. Use Value: Achieves 1.1 dB noise figure and 18 dB insertion gain at 900 MHz, preserving SNR before downconversion.	Use Scenario: Wideband amplification of 950–2150 MHz satellite IF signals in set-top box tuners. IC Role / Device Role / Timing Role: High-linearity driver amplifier after bandpass filtering, biased at I_C = 20 mA. Use Value: Delivers 17 dB insertion gain and −50 dB second-order distortion at 810 MHz, suppressing image interference.
DECT Cordless Base Station	Fiber-Optic Repeater Amplifier
Use Scenario: Transmit driver in 1880–1900 MHz DECT base station PA stage. IC Role / Device Role / Timing Role: Medium-power RF driver preceding final GaAs PA, operated at I_C = 20 mA, V_CE = 6 V. Use Value: Provides 13 dB G_UM at 2 GHz and 17 dBm P_1dB, enabling efficient signal boosting with low added noise.	Use Scenario: Post-detection amplification of 155 Mbps optical receiver outputs in telecom repeaters. IC Role / Device Role / Timing Role: DC-coupled broadband amplifier for recovered baseband signals, using dual-emitter configuration for balanced drive. Use Value: Maintains <1.6 dB noise figure at 2 GHz and supports >26 dBm third-order intercept, minimizing bit error rate in long-haul links.

Cellular Phone Front-End

Satellite TV Tuner LNA

Use Scenario: Low-noise amplification of 800–1000 MHz receive signals in GSM/EDGE handsets.

IC Role / Device Role / Timing Role: First-stage LNA in RF receiver chain, operating at I_C = 5 mA, V_CE = 6 V.

Use Value: Achieves 1.1 dB noise figure and 18 dB insertion gain at 900 MHz, preserving SNR before downconversion.

Use Scenario: Wideband amplification of 950–2150 MHz satellite IF signals in set-top box tuners.

IC Role / Device Role / Timing Role: High-linearity driver amplifier after bandpass filtering, biased at I_C = 20 mA.

Use Value: Delivers 17 dB insertion gain and −50 dB second-order distortion at 810 MHz, suppressing image interference.

DECT Cordless Base Station

Fiber-Optic Repeater Amplifier

Use Scenario: Transmit driver in 1880–1900 MHz DECT base station PA stage.

IC Role / Device Role / Timing Role: Medium-power RF driver preceding final GaAs PA, operated at I_C = 20 mA, V_CE = 6 V.

Use Value: Provides 13 dB G_UM at 2 GHz and 17 dBm P_1dB, enabling efficient signal boosting with low added noise.

Use Scenario: Post-detection amplification of 155 Mbps optical receiver outputs in telecom repeaters.

IC Role / Device Role / Timing Role: DC-coupled broadband amplifier for recovered baseband signals, using dual-emitter configuration for balanced drive.

Use Value: Maintains <1.6 dB noise figure at 2 GHz and supports >26 dBm third-order intercept, minimizing bit error rate in long-haul links.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN RF transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BFG520/XR	Reverse pinout (SOT143R): Pin 2 = emitter, Pin 3 = base - identical electrical specs	Requires PCB layout revision due to swapped base/emitter pins; same RF performance	Select when board layout accommodates reversed pinning or when sourcing flexibility is prioritized over footprint reuse
MRF581	Higher f_T (12 GHz), higher P_tot (500 mW), but larger SOT-343 package and no dual-emitter structure	Better suited for higher-power 2.4 GHz ISM applications; less optimal for ultra-low-noise 900 MHz LNA	Choose MRF581 only if system requires >20 dBm output or operation beyond 2.5 GHz; BFG520,235 remains superior for cost-sensitive, low-noise sub-2 GHz designs

Compared with BFG520/XR, the BFG520,235 offers identical RF performance but avoids PCB redesign; versus MRF581, it trades raw bandwidth and power for smaller footprint, lower noise at 900 MHz, and inherent thermal symmetry from dual emitters - making it the preferred choice for compact, battery-powered RF frontends.

Availability

BFG520,235 is available at Aetrix Electronics and suitable for cellular telephone RF frontends, satellite TV tuner LNAs, DECT cordless base stations, and fiber-optic repeater amplifiers requiring stable component supply across production lifecycles.

Supply support for BFG520,235 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and consumer markets.

The BFG520,235 belongs to NXP's legacy RF transistor product line, engineered specifically for high-gain, low-noise amplification in GHz-band wireless communication equipment where size, reliability, and noise performance are critical.

FAQ

What is the maximum operating frequency supported by the BFG520,235?

The BFG520,235 has a transition frequency (f_T) of 9 GHz, and its maximum unilateral power gain (G_UM) remains at 13 dB at 2 GHz. While usable gain extends beyond 2 GHz, stable amplifier design is typically targeted up to 2 GHz based on measured S-parameters and noise circle data in the official datasheet. The BFG520,235 is not characterized for reliable operation above 3 GHz.

Does the BFG520,235 require external matching networks for 50 Ω systems?

Yes, the BFG520,235 requires external input and output matching networks to achieve optimal noise figure (F_min = 1.1 dB) and maximum gain. Its S-parameters show non-50 Ω input (S₁₁) and output (S₂₂) reflection coefficients; Γ_opt is provided for noise matching, and load-pull data supports conjugate matching for power transfer. The BFG520,235 does not integrate internal matching.

What is the thermal resistance junction-to-soldering point for the BFG520,235?

The thermal resistance from junction to soldering point (R_{th j–s}) for the BFG520,235 is 290 K/W, measured up to a soldering point temperature (T_s) of 88 °C. This value assumes proper thermal conduction through the collector tab to the PCB copper pour; exceeding T_s = 88 °C triggers power derating per Figure 3 in the datasheet.

Can the BFG520,235 be used in Class A amplifier configurations?

Yes, the BFG520,235 is commonly operated in Class A for low-distortion LNA and driver stages. Its DC characteristics - including h_FE = 60–250 at I_C = 20 mA and V_CE = 6 V, and thermal rating of 300 mW - support stable Class A biasing. Measured intermodulation distortion (d₂ = −50 dB at I_C = 20 mA) confirms suitability for linear operation in this mode.

Is the BFG520,235 RoHS compliant?

Yes, the BFG520,235 is RoHS compliant. As a product released after 2006 under NXP Semiconductors' branding and documented in Rev. 04 (2007), it conforms to EU Directive 2002/95/EC. Lead-free soldering profiles and halogen-free packaging are consistent with NXP's post-2005 manufacturing standards, and no exemptions apply to this device.

BFG520,235 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

Package/Case:: TO-253-4, TO-253AA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Voltage - Collector Emitter Breakdown (Max):: 15V

Frequency - Transition:: 9GHz

Noise Figure (dB Typ @ f):: 1.1dB ~ 2.1dB @ 900MHz

Gain:: -

Power - Max:: 300mW

DC Current Gain (hFE) (Min) @ Ic, Vce:: 60 @ 20mA, 6V

Current - Collector (Ic) (Max):: 70mA

Operating Temperature:: 175°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-143B

BFG520,235 FAQ

1.How can I place an order for BFG520,235 through Aetrix?

Please submit a Request for Quotation (RFQ) for BFG520,235 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BFG520,235 reliable?

The price and inventory of BFG520,235 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BFG520,235 is usually 5 days.

3.What payment methods are accepted for BFG520,235?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BFG520,235 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BFG520,235?

BFG520,235 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BFG520,235 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BFG520,235?

For technical support, including BFG520,235 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BFG520,235 requirements.

6.How does Aetrix verify that BFG520,235 is sourced from the original manufacturer or authorized distributors?

All BFG520,235 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BFG520,235 meets industry standards.

7.What is the process for return or replacement of BFG520,235?

All BFG520,235 units undergo pre-shipment inspection (PSI). If there is an issue with BFG520,235, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BFG520,235 part is unused and in its original packaging.

Return procedure for BFG520,235:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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