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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > Single FETs, MOSFETs

NXP Semiconductors BF1105,215

Name: BF1105,215
Brand: NXP Semiconductors
SKU: BF1105,215
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BF1105,215

Manufacturer:: NXP Semiconductors

Category:: Single FETs, MOSFETs

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

Datasheet:: BF1105,215.pdf

Description:: RF MOSFET 5V SOT143B

Quantity:: RFQ Add To RFQ list

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Inventory:3,889

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Product details

Overview

BF1105 from NXP Semiconductors is an enhancement-type N-channel dual-gate MOSFET with source and substrate internally connected, designed for low-noise RF amplification in VHF/UHF tuners. It delivers 31 mS forward transfer admittance, 2.2 pF gate-1 input capacitance, and 1.7 dB noise figure at 800 MHz under 5 V supply.

For engineers reviewing the BF1105 datasheet, BF1105 pinout, BF1105 application, or BF1105 equivalent, this page provides verified pin configuration, cross-modulation performance at 40 dB AGC, thermal resistance (350 K/W), self-biasing drain current range (8–16 mA), and SOT143B package dimensions - all critical for tuner front-end design and RF gain stage selection.

Technical Context

The BF1105 operates as a common-source RF amplifier with internal self-biasing that stabilizes DC operating point and improves cross-modulation performance during automatic gain control (AGC). Its dual-gate architecture enables independent control of RF signal injection (gate 1) and bias/gain setting (gate 2).

Integrated protection diodes between each gate and source prevent damage from input voltage surges. The device is characterized at 25 °C with V_DS = 5 V and V_G2-S = 4 V, supporting stable operation up to 1 GHz while maintaining sub-2.5 dB noise figure and >38 dB power gain at 200 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS max	7 V - sets absolute maximum drain-source voltage for safe operation in 5 V tuner supplies
\|y_fs\| typ	31 mS - high transconductance enables strong RF signal amplification with minimal drive
C_ig1-ss typ	2.2 pF - low gate-1 input capacitance preserves Q-factor in tuned VHF/UHF tank circuits
F typ @ 800 MHz	1.7 dB - confirms suitability for low-noise preamplifier stages in TV and comms receivers
Xmod @ 40 dB AGC	100 dBμV - quantifies immunity to intermodulation distortion under strong-signal AGC conditions
T_j max	150 °C - defines junction temperature limit for reliability in compact tuner PCB layouts
R_{th j-a}	350 K/W - indicates thermal performance in free-air mounting, guiding heatsinking decisions

Pinout & Package

BF1105 is housed in the SOT143B plastic surface-mounted package (3.0 × 1.4 × 1.1 mm), optimized for RF layout with short lead inductance and controlled parasitics.

Pin/Terminal	Circuit Role	Design Meaning
1	Source	Common reference node for both gates and drain; internally tied to substrate for enhanced stability
2	Drain	RF output terminal; connects to tuned collector load or next-stage input via coupling capacitor
3	Gate 2	Bias and AGC control input; sets quiescent current and gain level without modulating RF path
4	Gate 1	Primary RF signal input; isolated from Gate 2 to minimize feedthrough and improve reverse isolation

Key Features

Feature	Design Value
Dual-gate architecture with isolated inputs	Enables simultaneous RF signal injection (G1) and independent gain/bias control (G2), reducing AGC-induced distortion
Integrated gate-source protection diodes	Prevents electrostatic damage and transient overvoltage failure without external clamping components
Self-biasing circuit	Stabilizes I_D between 8–16 mA at V_DS = 5 V and V_G2-S = 4 V, simplifying bias network design
Low Crss (25–40 fF)	Minimizes Miller effect and maintains wideband stability up to 1 GHz in common-source configurations
High yfs/Cig1 ratio	Delivers superior gain-per-capacitance - critical for maximizing selectivity and sensitivity in miniature tuner modules

Applications

Television Tuner Front-End	Professional UHF Receiver
Use Scenario: Amplifying weak terrestrial broadcast signals in analog/digital TV tuner modules operating at 47–862 MHz. IC Role / Device Role / Timing Role: Low-noise RF preamplifier stage with AGC-controlled gain using Gate 2, preserving signal integrity before mixer. Use Value: Achieves 1.7 dB noise figure and 100 dBμV cross-modulation threshold at 40 dB AGC, enabling reliable reception under multipath and co-channel interference.	Use Scenario: Signal amplification in portable UHF two-way radios and spectrum analyzers requiring stable gain across 300–900 MHz. IC Role / Device Role / Timing Role: Dual-gate RF amplifier where Gate 1 receives antenna signal and Gate 2 accepts system-level AGC voltage for dynamic range control. Use Value: Delivers 38 dB power gain at 200 MHz and 20 dB at 800 MHz with <2.5 dB noise figure, supporting wideband sensitivity without external bias adjustment.
VHF Aircraft Communication Receiver	Lab-Grade RF Test Equipment
Use Scenario: First-stage amplification in aviation VHF COM band (118–137 MHz) receivers where signal fidelity and AGC linearity are mission-critical. IC Role / Device Role / Timing Role: Low-noise amplifier with internal self-biasing, eliminating discrete bias resistors and reducing component count in constrained avionics PCBs. Use Value: Maintains 1.7–2.5 dB noise figure and stable 31 mS yfs across temperature, ensuring consistent receiver sensitivity during flight envelope changes.	Use Scenario: Calibration-grade RF gain block in signal generators and vector network analyzers requiring repeatable small-signal parameters. IC Role / Device Role / Timing Role: Fixed-gain RF amplifier stage with known scattering parameters (S21 = 3.06 @ 50 MHz) and low reverse isolation (S12 ≈ 0.000). Use Value: Provides traceable forward transfer admittance (25–31 mS) and predictable Crss (25–40 fF), enabling accurate modeling and compensation in metrology-grade designs.

Television Tuner Front-End

Professional UHF Receiver

Use Scenario: Amplifying weak terrestrial broadcast signals in analog/digital TV tuner modules operating at 47–862 MHz.

IC Role / Device Role / Timing Role: Low-noise RF preamplifier stage with AGC-controlled gain using Gate 2, preserving signal integrity before mixer.

Use Value: Achieves 1.7 dB noise figure and 100 dBμV cross-modulation threshold at 40 dB AGC, enabling reliable reception under multipath and co-channel interference.

Use Scenario: Signal amplification in portable UHF two-way radios and spectrum analyzers requiring stable gain across 300–900 MHz.

IC Role / Device Role / Timing Role: Dual-gate RF amplifier where Gate 1 receives antenna signal and Gate 2 accepts system-level AGC voltage for dynamic range control.

Use Value: Delivers 38 dB power gain at 200 MHz and 20 dB at 800 MHz with <2.5 dB noise figure, supporting wideband sensitivity without external bias adjustment.

VHF Aircraft Communication Receiver

Lab-Grade RF Test Equipment

Use Scenario: First-stage amplification in aviation VHF COM band (118–137 MHz) receivers where signal fidelity and AGC linearity are mission-critical.

IC Role / Device Role / Timing Role: Low-noise amplifier with internal self-biasing, eliminating discrete bias resistors and reducing component count in constrained avionics PCBs.

Use Value: Maintains 1.7–2.5 dB noise figure and stable 31 mS yfs across temperature, ensuring consistent receiver sensitivity during flight envelope changes.

Use Scenario: Calibration-grade RF gain block in signal generators and vector network analyzers requiring repeatable small-signal parameters.

IC Role / Device Role / Timing Role: Fixed-gain RF amplifier stage with known scattering parameters (S21 = 3.06 @ 50 MHz) and low reverse isolation (S12 ≈ 0.000).

Use Value: Provides traceable forward transfer admittance (25–31 mS) and predictable Crss (25–40 fF), enabling accurate modeling and compensation in metrology-grade designs.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-gate MOSFET amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BF1105R	SOT143R package with reversed pinning (1=source, 2=drain, 4=gate2, 3=gate1); identical electrical specs	Requires PCB layout revision due to swapped gate pin order; same RF performance and bias behavior	Select when board space allows reverse-pin footprint or when sourcing legacy stock with SOT143R marking code NAp
BF1105WR	SOT343R package (2.2 × 1.35 × 0.9 mm); smaller footprint but same pinout orientation as BF1105R	Enables higher-density tuner modules; thermal resistance increases slightly due to reduced pad area	Choose for miniaturized designs where 25% smaller footprint justifies marginally higher R_{th j-a} (not specified, but inferred from size reduction)

Compared with BF1105, BF1105R offers identical RF performance in a mechanically distinct SOT143R outline requiring layout adaptation, while BF1105WR delivers the same functionality in a 2.2 mm × 1.35 mm SOT343R package - prioritizing board area savings over thermal margin in space-constrained tuner assemblies.

Availability

BF1105 is available at Aetrix Electronics and suitable for television tuners, professional UHF communications equipment, and VHF aircraft receivers requiring stable component supply and long-term obsolescence management.

Supply support for BF1105 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 mixed-signal solutions for consumer, industrial, and communications markets.

The BF1105 belongs to NXP's legacy dual-gate MOSFET product line, engineered specifically for low-noise, high-gain VHF/UHF RF amplification in tuner and receiver front-ends with integrated self-biasing and ESD protection.

FAQ

What is the maximum drain-source voltage rating for BF1105?

The BF1105 has a maximum drain-source voltage (V_DS) rating of 7 V, as defined in its Absolute Maximum Ratings table. This rating applies under continuous DC conditions with proper thermal management and is intended for use in 5 V supply systems such as television tuners. Exceeding 7 V risks permanent device failure per IEC 60134 limiting values.

Does BF1105 require external bias resistors?

No, BF1105 does not require external bias resistors due to its integrated self-biasing circuit. When operated at V_DS = 5 V and V_G2-S = 4 V, the BF1105 delivers a self-biasing drain current (I_DSX) between 8 mA and 16 mA, establishing a stable quiescent point without discrete components - simplifying tuner front-end design and improving thermal drift performance.

What is the noise figure of BF1105 at 800 MHz?

The BF1105 achieves a typical noise figure (F) of 1.7 dB at 800 MHz, measured under standard conditions: V_DS = 5 V, V_G2-S = 4 V, I_D = 12 mA, and Y_S = Y_{S opt}. The maximum specified noise figure is 2.5 dB, confirming its suitability for low-noise amplifier stages in UHF receivers and professional communication equipment where signal-to-noise ratio is critical.

How does BF1105 handle input voltage surges?

The BF1105 incorporates integrated diodes between each gate (G1 and G2) and the source terminal to protect against excessive input voltage surges. These on-chip diodes clamp transient voltages before they reach the sensitive gate oxide, eliminating the need for external TVS or series resistors in most tuner applications - enhancing robustness while reducing bill-of-materials count.

What package type is used for BF1105?

The BF1105 is packaged in the SOT143B plastic surface-mounted package, measuring 3.0 mm × 1.4 mm × 1.1 mm. This outline features standard pinning (Pin 1 = source, Pin 2 = drain, Pin 3 = gate 2, Pin 4 = gate 1) and is optimized for RF performance with low parasitic inductance - distinct from the SOT143R and SOT343R variants used for BF1105R and BF1105WR respectively.

BF1105,215 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Technology:: MOSFET (Metal Oxide)

Configuration:: N-Channel Dual Gate

Frequency:: 800MHz

Gain:: 20dB

Voltage - Test:: 5 V

Current Rating (Amps):: 30mA

Noise Figure:: 1.7dB

Current - Test:: -

Power - Output:: -

Voltage - Rated:: 7 V

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-143B

BF1105,215 FAQ

1.How can I place an order for BF1105,215 through Aetrix?

Please submit a Request for Quotation (RFQ) for BF1105,215 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 BF1105,215 reliable?

The price and inventory of BF1105,215 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BF1105,215 is usually 5 days.

3.What payment methods are accepted for BF1105,215?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BF1105,215 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BF1105,215?

BF1105,215 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BF1105,215 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 BF1105,215?

For technical support, including BF1105,215 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BF1105,215 requirements.

6.How does Aetrix verify that BF1105,215 is sourced from the original manufacturer or authorized distributors?

All BF1105,215 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 BF1105,215 meets industry standards.

7.What is the process for return or replacement of BF1105,215?

All BF1105,215 units undergo pre-shipment inspection (PSI). If there is an issue with BF1105,215, 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 BF1105,215 part is unused and in its original packaging.

Return procedure for BF1105,215:

1.Submit a request within 90 days.

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

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