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NXP Semiconductors BF904,235
- Part No.:
- BF904,235
- Manufacturer:
- NXP Semiconductors
- Category:
- Single FETs, MOSFETs
- Package:
- SOT-143R
- Datasheet:
-
BF904,235.pdf
- Description:
- RF MOSFET 5V SOT143R
- Quantity:
- Payment:
- Shipping:
Inventory:8,724
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Product details
Overview
BF904,235 from NXP Semiconductors is an N-channel dual-gate MOSFET designed for VHF/UHF RF amplification in 3–7 V supply systems, featuring 25 mS typical forward transfer admittance, 2.2 pF input capacitance at gate 1, and 2 dB noise figure at 800 MHz - deployed in television tuners and professional communications receivers.
For engineers reviewing the BF904,235 datasheet, BF904,235 pinout, BF904,235 application, or BF904,235 equivalent, this device requires attention to AGC-controlled cross-modulation performance, dual-gate biasing configuration (gate 1 for signal input, gate 2 for AGC control), thermal derating above 50 °C ambient, and SOT143B package layout constraints.
Technical Context
The BF904,235 implements a short-channel enhancement-mode MOSFET architecture with internally connected source and substrate, enabling stable gain control under automatic gain control (AGC) conditions. Its dual-gate structure separates RF signal injection (gate 1) from AGC voltage application (gate 2), supporting low-noise amplification up to 1 GHz.
It operates with a 5 V nominal supply, delivers 10 mA drain current at VDS = 5 V and VG2-S = 4 V, and maintains ≤2.8 dB noise figure across 200–800 MHz - validated under pulsed conditions at Tj = 25 °C with 120 kΩ gate 1 bias resistor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDS max | 7 V - maximum drain-source voltage before breakdown; sets upper limit for supply rail and signal swing in tuner front-ends |
| |yfs| typ | 25 mS - forward transfer admittance at 25 °C; determines small-signal gain per unit input voltage in common-source configuration |
| Cig1-s typ | 2.2 pF - input capacitance at gate 1; directly impacts input matching network design and bandwidth in 50 Ω RF stages |
| F typ @ 800 MHz | 2 dB - noise figure at 800 MHz; critical for maintaining SNR in UHF receiver LNA stages |
| Ptot max | 200 mW - total power dissipation at Tamb ≤ 50 °C; defines thermal management requirements on PCB |
| VG1-S(th) | 0.3–1.0 V - gate 1-source threshold voltage; establishes minimum AGC voltage needed to maintain conduction |
| Crs max | 35 fF - reverse transfer capacitance; limits stability margin and dictates neutralization needs above 500 MHz |
Pinout & Package
BF904,235 is housed in a plastic microminiature SOT143B surface-mount package (3.0 × 1.4 × 1.1 mm), optimized for high-frequency layout with short internal leads and defined thermal path to source pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - s, b | Source and substrate | Common reference node for both gates and drain; must be low-inductance RF ground connection |
| 2 - d | Drain | RF output node; connects to tuned load or next-stage input; requires impedance-matching trace |
| 3 - g2 | Gate 2 | AGC control terminal; biased at 4 V for optimal cross-modulation performance; high-impedance DC node |
| 4 - g1 | Gate 1 | RF signal input terminal; isolated from gate 2 to prevent AGC feedthrough; matched to 50 Ω via external network |
Key Features
| Feature | Design Value |
|---|---|
| Dual-gate architecture with internal source-substrate tie | Enables independent RF signal injection (g1) and AGC voltage application (g2) without external bias network coupling |
| Low 2.2 pF Cig1-s and 35 fF Crs | Supports stable broadband amplification up to 1 GHz with minimal neutralization complexity |
| 2 dB noise figure at 800 MHz | Meets stringent SNR requirements in UHF TV tuner IF/RF amplifier stages |
| Superior cross-modulation suppression | Unwanted voltage <120 dBµV at 50 MHz gain reduction - verified per Fig.6 test setup with RG1 = 120 kΩ |
| 5 V supply optimization | Guaranteed operation at 3–7 V range; eliminates need for dedicated 12 V rails in modern compact tuner modules |
Applications
| Television Tuner Front-End | Professional UHF Receiver |
|---|---|
Use Scenario: Amplifying weak terrestrial broadcast signals in analog/digital TV tuners operating at 47–862 MHz. IC Role / Device Role / Timing Role: Low-noise RF amplifier stage with AGC-controlled gain stabilization during signal fading. Use Value: Maintains 2 dB noise figure and >40 dB gain reduction linearity while suppressing cross-modulation distortion below −120 dBµV. |
Use Scenario: First-stage amplification in portable UHF land-mobile radios and spectrum analyzers. IC Role / Device Role / Timing Role: High-linearity, low-noise preamplifier with dual-gate AGC interface for dynamic range extension. Use Value: Delivers 25 mS transconductance and 30 mA ID capability to sustain >15 dBm output P1dB under 5 V supply. |
| RF Signal Generator Output Stage | Test Equipment IF Amplifier |
Use Scenario: Final gain block in benchtop RF signal generators covering 100–1000 MHz. IC Role / Device Role / Timing Role: Fixed-gain driver amplifier with gate 2 used for amplitude calibration offset trimming. Use Value: Achieves <±0.2 dB gain flatness over 500 MHz bandwidth due to low Crs and controlled yfs temperature coefficient. |
Use Scenario: Intermediate frequency amplification in digital oscilloscopes and logic analyzers (200–500 MHz IF). IC Role / Device Role / Timing Role: Low-distortion, wideband IF amplifier with precise gain control via gate 2 voltage. Use Value: Enables 1% cross-modulation suppression at 30 dB gain reduction - critical for multi-tone spectral purity verification. |
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 |
|---|---|---|---|
| BF998,215 | Higher |yfs| (35 mS typ), lower Cig1-s (1.8 pF), but 3.5 V max VDS; SOT143B package | Better gain-bandwidth product above 1 GHz, but unsuitable for 7 V supply designs | Select BF998,215 only when operating below 5 V and requiring >1 GHz bandwidth |
| NE3210M04 | Single-gate GaAs FET; 0.6 dB NF @ 2 GHz; 5 V supply; SOT343 package; no internal AGC path | Superior noise performance at microwave frequencies, but lacks dual-gate AGC functionality | Choose NE3210M04 for ultra-low-noise 2 GHz LNA where AGC is implemented externally |
Compared with BF904,235, BF998,215 offers higher gain and extended frequency response but reduced voltage headroom, while NE3210M04 provides superior noise figure at microwave bands but requires external AGC circuitry - neither is pin-compatible, and both demand revised biasing and matching networks.
Availability
BF904,235 is available at Aetrix Electronics and suitable for television tuner front-ends, professional UHF receivers, and RF signal generator output stages requiring stable component supply across long-lifecycle consumer and industrial programs.
Supply support for BF904,235 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 applications.
The BF904,235 belongs to NXP's legacy RF transistor product line, engineered specifically for high-performance, low-voltage dual-gate amplification in broadcast and communications equipment.
FAQ
What is the maximum drain-source voltage rating for BF904,235?
The BF904,235 has a maximum drain-source voltage (VDS) rating of 7 V, as specified in the Limiting Values table. This rating applies under all operating conditions and must not be exceeded to avoid permanent device damage. The BF904,235 is optimized for 3–7 V supply operation, with typical use at 5 V in television tuner applications.
How does BF904,235 achieve low cross-modulation during AGC operation?
The BF904,235 achieves low cross-modulation through its internal bias circuit and source-substrate interconnection, which stabilizes channel conductivity during gate 2 (AGC) voltage variation. Measured data shows unwanted voltage remains below 120 dBµV at 50 MHz gain reduction - a result confirmed in Fig.6 using the test setup in Fig.20 with RG1 = 120 kΩ.
What is the thermal resistance from junction to ambient for BF904,235?
The BF904,235 has a thermal resistance from junction to ambient (Rth j-a) of 500 K/W when mounted on a standard PCB, as stated in the Thermal Characteristics table. This value assumes Tamb ≤ 50 °C and defines the required board copper area and airflow for safe 200 mW power dissipation.
Can BF904,235 be used at 800 MHz with acceptable noise performance?
Yes, the BF904,235 delivers a typical noise figure of 2 dB at 800 MHz under standard test conditions (VDS = 5 V, VG2-S = 4 V, ID = 10 mA), as documented in the Dynamic Characteristics table. This makes it suitable for UHF receiver front-ends where SNR preservation is critical.
What is the pin configuration difference between BF904,235 and BF904R?
The BF904,235 uses the SOT143B package with pin 1 = source/bulk, pin 2 = drain, pin 3 = gate 2, pin 4 = gate 1. In contrast, BF904R uses the SOT143R package with reversed pinning: pin 1 = source/bulk, pin 2 = drain, pin 3 = gate 1, pin 4 = gate 2 - making them non-interchangeable without PCB layout revision.
BF904,235 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- SOT-143R
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Technology:
- MOSFET (Metal Oxide)
- Configuration:
- N-Channel Dual Gate
- Frequency:
- 200MHz
- Gain:
- -
- Voltage - Test:
- 5 V
- Current Rating (Amps):
- 30mA
- Noise Figure:
- 1dB
- Current - Test:
- 10 mA
- Power - Output:
- -
- Voltage - Rated:
- 7 V
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-143R
BF904,235 FAQ
1.How can I place an order for BF904,235 through Aetrix?
Please submit a Request for Quotation (RFQ) for BF904,235 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 BF904,235 reliable?
The price and inventory of BF904,235 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BF904,235 is usually 5 days.
3.What payment methods are accepted for BF904,235?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BF904,235 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BF904,235?
BF904,235 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BF904,235 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 BF904,235?
For technical support, including BF904,235 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BF904,235 requirements.
6.How does Aetrix verify that BF904,235 is sourced from the original manufacturer or authorized distributors?
All BF904,235 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 BF904,235 meets industry standards.
7.What is the process for return or replacement of BF904,235?
All BF904,235 units undergo pre-shipment inspection (PSI). If there is an issue with BF904,235, 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 BF904,235 part is unused and in its original packaging.
Return procedure for BF904,235:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BF904,235 Tags
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SAV-551+
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TAV2-501+
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AFT05MS004NT1
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SAV-541+
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CE3512K2-C1
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AFM907NT1
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SKY65050-372LF
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CE3520K3-C1
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