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

NXP Semiconductors BFG21W,115

Name: BFG21W,115
Brand: NXP Semiconductors
SKU: BFG21W,115
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BFG21W,115

Manufacturer:: NXP Semiconductors

Category:: Bipolar RF Transistors

Package:: SC-82A, SOT-343

Datasheet:: BFG21W,115.pdf

Description:: RF TRANS NPN 4.5V 18GHZ CMPAK-4

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BFG21W,115 from NXP Semiconductors is an NPN double polysilicon bipolar UHF power transistor with buried layer, designed for low-voltage medium-power applications at 1.9 GHz. It delivers 26 dBm output power, ≥10 dB power gain, and 55% collector efficiency in pulsed class-AB operation at V_CE = 3.6 V, housed in a SOT343R 4-pin dual-emitter plastic package.

For engineers reviewing the BFG21W,115 datasheet, BFG21W,115 pinout, BFG21W,115 application, or BFG21W,115 equivalent, key selection criteria include RF performance at 1.9 GHz, thermal resistance (150 K/W), ruggedness under VSWR = 6:1 mismatch, DC current gain (h_FE = 40–100), and SOT343R package compatibility for handheld radio front-end designs.

Technical Context

The BFG21W,115 operates as a common-emitter class-AB RF power amplifier with pulsed duty cycle δ < 1:2 and pulse width t_p = 5 ms. Its design supports linear and non-linear operation up to 1.9 GHz, with verified ruggedness against VSWR = 6:1 load mismatch at 26 dBm output.

Thermal management relies on junction-to-solder-point thermal resistance of 150 K/W, referenced to emitter pin soldering point temperature (T_s ≤ 60 °C). Device characterization is specified at T_j = 25 °C, with absolute maximum ratings including V_CEO = 4.5 V, I_C = 500 mA, and P_tot = 600 mW.

Key Specifications

Parameter	Value and Actual Design Meaning
f_T	18 GHz - ensures stable high-frequency amplification capability beyond 1.9 GHz operating band
P_L	26 dBm (400 mW) - sufficient RF output power for DECT/PHS handset final-stage amplification
G_p	≥10 dB - enables single-stage gain without cascading, reducing board space and matching complexity
η_C	55% typical - improves battery life in portable 1.9 GHz transceivers by minimizing DC power waste
R_{th j-s}	150 K/W - defines thermal path limitation; requires PCB copper area under emitter pins for T_s ≤ 60 °C compliance
V_(BR)CEO	4.5 V - sets maximum safe supply voltage for class-AB biasing in low-voltage handheld systems
h_FE	40–100 at I_C = 200 mA - supports predictable DC bias network design for stable quiescent current setting

Pinout & Package

Package: SOT343R - plastic surface-mounted, 4-pin dual-emitter package with reverse pinning (top view: Pin 1–2–4–3 clockwise). Dimensions: 2.2 × 1.35 × 0.95 mm (L × W × H); lead pitch 0.65 mm; marking code "P1".

Pin/Terminal	Circuit Role	Design Meaning
1, 3	Emitter	Dual-emitter configuration enables symmetrical grounding and improved thermal dissipation via two parallel solder points
2	Base	DC bias and RF input node; requires impedance-matched 50 Ω source for optimal G_p and stability
4	Collector	RF output node; connects to tuned matching network (e.g., stripline L1/L4 per Fig.4) for 1.9 GHz load pull

Key Features

Feature	Design Value
High power gain	≥10 dB at 1.9 GHz enables compact RF front-end architecture with minimal active stages
High efficiency	55% collector efficiency reduces heat generation and extends battery runtime in portable radios
1.9 GHz operating area	Validated RF performance at exact DECT/PHS/DCS1800 frequency band - no derating required
Ruggedness	Withstands VSWR = 6:1 mismatch at full 26 dBm output - eliminates need for external circulator in cost-sensitive handsets
Dual-emitter SOT343R	Two emitter pins lower thermal resistance and improve solder joint reliability versus single-emitter alternatives

Applications

DECT Handset Power Amplifier	PHS Terminal RF Output Stage
Use Scenario: Final-stage RF power amplification in 1.9 GHz cordless telephone handsets compliant with ETSI EN 300 175. IC Role / Device Role / Timing Role: NPN bipolar UHF power transistor operating in pulsed class-AB mode to deliver 26 dBm output with ≥10 dB gain. Use Value: Meets DECT spectral mask and output power requirements while maintaining 55% efficiency to extend talk time on single-cell Li-ion batteries.	Use Scenario: Common-emitter output stage in Japanese Personal Handy-phone System (PHS) subscriber terminals operating at 1.9 GHz. IC Role / Device Role / Timing Role: Medium-power RF transistor driving antenna interface with linear/non-linear modulation support for π/4-DQPSK. Use Value: Dual-emitter thermal design sustains continuous transmission bursts without thermal shutdown, meeting PHS 100 ms frame timing constraints.
DCS1800 Driver Amplifier	1.9 GHz Wireless Test Fixture
Use Scenario: Driver stage preceding a higher-power final amplifier in DCS1800 base station or repeater subsystems. IC Role / Device Role / Timing Role: Low-voltage (3.6 V) RF gain block delivering 26 dBm into 50 Ω load with matched input/output impedance per Fig.6/Fig.7. Use Value: Enables compact, low-cost driver solution without DC-DC conversion, leveraging BFG21W,115's V_CEO = 4.5 V rating for margin over 3.6 V rail.	Use Scenario: Calibration and validation reference device in 1.9 GHz RF test benches using standardized class-AB test circuit (Fig.4/Fig.5). IC Role / Device Role / Timing Role: Characterized UHF transistor with documented Z_i, Z_L, G_p, and η_C curves for fixture verification and de-embedding. Use Value: Known thermal resistance (150 K/W) and ruggedness allow repeatable pulsed measurements at 5 ms, supporting traceable RF power calibration.

DECT Handset Power Amplifier

PHS Terminal RF Output Stage

Use Scenario: Final-stage RF power amplification in 1.9 GHz cordless telephone handsets compliant with ETSI EN 300 175.

IC Role / Device Role / Timing Role: NPN bipolar UHF power transistor operating in pulsed class-AB mode to deliver 26 dBm output with ≥10 dB gain.

Use Value: Meets DECT spectral mask and output power requirements while maintaining 55% efficiency to extend talk time on single-cell Li-ion batteries.

Use Scenario: Common-emitter output stage in Japanese Personal Handy-phone System (PHS) subscriber terminals operating at 1.9 GHz.

IC Role / Device Role / Timing Role: Medium-power RF transistor driving antenna interface with linear/non-linear modulation support for π/4-DQPSK.

Use Value: Dual-emitter thermal design sustains continuous transmission bursts without thermal shutdown, meeting PHS 100 ms frame timing constraints.

DCS1800 Driver Amplifier

1.9 GHz Wireless Test Fixture

Use Scenario: Driver stage preceding a higher-power final amplifier in DCS1800 base station or repeater subsystems.

IC Role / Device Role / Timing Role: Low-voltage (3.6 V) RF gain block delivering 26 dBm into 50 Ω load with matched input/output impedance per Fig.6/Fig.7.

Use Value: Enables compact, low-cost driver solution without DC-DC conversion, leveraging BFG21W,115's V_CEO = 4.5 V rating for margin over 3.6 V rail.

Use Scenario: Calibration and validation reference device in 1.9 GHz RF test benches using standardized class-AB test circuit (Fig.4/Fig.5).

IC Role / Device Role / Timing Role: Characterized UHF transistor with documented Z_i, Z_L, G_p, and η_C curves for fixture verification and de-embedding.

Use Value: Known thermal resistance (150 K/W) and ruggedness allow repeatable pulsed measurements at 5 ms, supporting traceable RF power calibration.

Equivalent & Alternatives

The following parts are listed as comparable options for similar UHF power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BFG22W,115	Same SOT343R package; higher f_T = 22 GHz; identical pinout and bias conditions	Optimized for wider bandwidth applications beyond 1.9 GHz (e.g., early 2.4 GHz ISM prototypes)	Select BFG22W,115 only if system bandwidth exceeds 1.9 GHz and gain flatness above 2 GHz is required
MRF581,112	SOT23-3 package (3-pin, single emitter); lower P_L = 23 dBm; R_{th j-s} = 220 K/W	Targeted at lower-power, cost-sensitive 1.9 GHz modules where thermal budget allows higher junction rise	Choose MRF581,112 when board space is constrained and 3 dB lower output power is acceptable

Compared with BFG21W,115, BFG22W,115 offers extended frequency headroom but no improvement in 1.9 GHz efficiency or ruggedness, while MRF581,112 trades thermal performance and output power for smaller footprint and lower unit cost in less demanding applications.

Availability

BFG21W,115 is available at Aetrix Electronics and suitable for DECT handset manufacturing, PHS terminal production, and 1.9 GHz wireless infrastructure requiring stable component supply, long-term obsolescence management, and traceable lot-level documentation.

Supply support for BFG21W,115 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 specializing in high-performance RF, analog, and power management solutions for communications, automotive, and industrial markets.

The BFG21W,115 belongs to NXP's legacy UHF bipolar transistor product line, engineered specifically for low-voltage, high-efficiency RF power amplification in 1.9 GHz portable communication devices.

FAQ

What is the maximum safe operating voltage for BFG21W,115 in a 1.9 GHz power amplifier?

The BFG21W,115 has a maximum collector-emitter voltage (V_CEO) rating of 4.5 V under open-base conditions. For reliable operation in pulsed class-AB mode at 1.9 GHz, the recommended DC supply is 3.6 V - this provides 0.9 V headroom below the absolute maximum and aligns with the Quick Reference Data test condition where BFG21W,115 delivers 26 dBm output with ≥10 dB gain and 55% efficiency.

Does BFG21W,115 support both linear and non-linear modulation schemes?

Yes, the BFG21W,115 is explicitly characterized for both linear and non-linear operation per its official product specification. Its 1.9 GHz RF performance data - including power gain, collector efficiency, and load impedance curves - were measured under pulsed class-AB conditions compatible with π/4-DQPSK (PHS) and GFSK (DECT), confirming suitability for both constant-envelope and variable-envelope modulation formats.

How is thermal management implemented for BFG21W,115 in handheld radio designs?

Thermal management for BFG21W,115 relies on its dual-emitter SOT343R package: pins 1 and 3 serve as parallel emitter terminals, enabling direct thermal conduction to PCB copper planes. The datasheet specifies R_{th j-s} = 150 K/W referenced to the emitter soldering point (T_s ≤ 60 °C), requiring adequate copper area and via stitching beneath both emitter pads to maintain junction temperature within the 150 °C limit during 5 ms pulses at 26 dBm.

Is BFG21W,115 qualified for automotive applications?

No, BFG21W,115 is not automotive-qualified. Per NXP's disclaimers in the 1998 product specification, the device is intended for consumer and industrial portable radio equipment only. It lacks AEC-Q101 qualification, has no automotive-grade screening, and is not tested to automotive temperature or reliability standards - use in automotive systems is unsupported and at the customer's sole risk.

What is the DC current gain range of BFG21W,115 and how is it used in bias design?

The BFG21W,115 exhibits DC current gain (h_FE) between 40 and 100 when measured at I_C = 200 mA and V_CE = 2 V. This range informs base resistor selection in the common-emitter bias network to achieve target quiescent current (I_CQ = 1 mA per Quick Reference Data), ensuring stable class-AB operation across process variation while maintaining thermal safety margins in the SOT343R package.

BFG21W,115 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

Package/Case:: SC-82A, SOT-343

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Voltage - Collector Emitter Breakdown (Max):: 4.5V

Frequency - Transition:: 18GHz

Noise Figure (dB Typ @ f):: -

Gain:: -

Power - Max:: 600mW

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 200mA, 2V

Current - Collector (Ic) (Max):: 500mA

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: CMPAK-4

BFG21W,115 FAQ

1.How can I place an order for BFG21W,115 through Aetrix?

Please submit a Request for Quotation (RFQ) for BFG21W,115 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 BFG21W,115 reliable?

The price and inventory of BFG21W,115 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BFG21W,115 is usually 5 days.

3.What payment methods are accepted for BFG21W,115?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BFG21W,115 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BFG21W,115?

BFG21W,115 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BFG21W,115 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 BFG21W,115?

For technical support, including BFG21W,115 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BFG21W,115 requirements.

6.How does Aetrix verify that BFG21W,115 is sourced from the original manufacturer or authorized distributors?

All BFG21W,115 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 BFG21W,115 meets industry standards.

7.What is the process for return or replacement of BFG21W,115?

All BFG21W,115 units undergo pre-shipment inspection (PSI). If there is an issue with BFG21W,115, 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 BFG21W,115 part is unused and in its original packaging.

Return procedure for BFG21W,115:

1.Submit a request within 90 days.

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

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