NXP Semiconductors BF1204,115

Overview

BF1204 from NXP Semiconductors is a dual N-channel dual-gate MOSFET designed for low-noise, gain-controlled RF amplification in VHF/UHF tuner front-ends. It integrates two matched amplifiers sharing source and gate-2 terminals, delivers 30 mS typical forward transfer admittance at 1 MHz, achieves 1.1 dB noise figure at 800 MHz, and operates with 3–9 V supply voltage in analog/digital TV tuners and professional comms equipment.

For engineers reviewing the BF1204 datasheet, BF1204 pinout, BF1204 application, or BF1204 equivalent, this page provides verified package mapping (SOT363), confirmed dual-gate topology, cross-modulation performance at 40 dB AGC (100–105 dBµV), thermal resistance (240 K/W), and validated alternatives for VHF/UHF amplifier replacement.

Technical Context

The BF1204 implements a monolithic dual-gate structure where Gate 1 controls RF signal amplification and Gate 2 enables automatic gain control (AGC) without degrading cross-modulation performance. Internal bias networks stabilize DC operating points, while integrated gate-source diodes protect against input voltage surges up to ±10 mA gate current.

Each MOSFET section features shared source and gate-2 leads, enabling compact dual-amplifier configurations with independent Gate 1 control. The device exhibits 15 fF reverse transfer capacitance and 1.7–2.2 pF input capacitance at Gate 1, supporting stable broadband operation up to 1 GHz with measured S21 magnitude of 2.55 at 800 MHz.

Key Specifications

Pinout & Package

SOT363 micro-miniature plastic surface-mounted package (6-lead, 2.2 × 1.8 mm footprint) with exposed source pad for thermal conduction and ESD protection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BF1204, BF1205,115 offers marginally better noise and gain specs in identical packaging, while BF998,115 sacrifices integration for higher single-device yfs but adds design complexity for dual-channel use.

Availability

BF1204 is available at Aetrix Electronics and suitable for analog/digital TV tuners, professional UHF communications receivers, and CATV distribution amplifier stages requiring stable component supply across extended production lifecycles.

Supply support for BF1204 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 leader specializing in high-performance RF, analog, and mixed-signal solutions for consumer, industrial, and communications markets.

The BF1204 belongs to NXP's legacy RF transistor product line, engineered specifically for gain-stable, low-noise VHF/UHF amplification in broadcast tuner applications with integrated AGC capability.

FAQ

What is the maximum drain-source voltage rating for the BF1204?

The BF1204 has a maximum drain-source voltage (V_DS) rating of 10 V, as specified in the Limiting Values table. This rating applies per MOSFET section under all operating conditions and must not be exceeded to prevent permanent device damage. The BF1204 is intended for low-voltage RF amplifier applications, not high-power switching, and its 10 V limit aligns with typical 5–9 V supply rails used in TV tuner designs.

How does the BF1204 achieve superior cross-modulation performance during AGC?

The BF1204 achieves superior cross-modulation performance through internal bias circuits that stabilize DC operating points across varying AGC voltages and integrated diodes between gates and source that suppress input transients. At 40 dB AGC, the BF1204 delivers 100–105 dBµV cross-modulation input level, verified in the Quick Reference Data table. This performance stems from matched dual-gate sections sharing Gate 2, minimizing gain mismatch and intermodulation distortion during dynamic range compression.

What is the thermal resistance from junction to soldering point for the BF1204?

The BF1204 has a thermal resistance from junction to soldering point (R_{th j-s}) of 240 K/W, as documented in the Thermal Characteristics table. This value assumes Ts ≤ 102 °C and reflects heat transfer through the source lead to the PCB copper. Designers must ensure adequate copper pour under Pin 5 (source) to maintain junction temperature below 150 °C at 200 mW total power dissipation, especially in enclosed tuner modules.

Can the BF1204 be used in 1 GHz applications?

The BF1204 is characterized up to 1000 MHz in its scattering parameter table, with S21 magnitude of 2.41 and phase of 100.24° at 1 GHz. While usable near 1 GHz, its forward transfer admittance drops above 800 MHz and noise figure rises-measured at 1.8 dB max at 800 MHz. For robust 1 GHz operation, verify gain flatness and noise performance in the target circuit; the BF1204 is optimized for VHF/UHF (30–900 MHz), not millimeter-wave bands.

What package type does the BF1204 use and what are its key mechanical dimensions?

The BF1204 uses the SOT363 micro-miniature plastic surface-mounted package, also known as SC-88. Its footprint measures 2.2 mm × 1.8 mm with 0.65 mm lead pitch, and overall height is 1.15 mm max. The package features six leads in a single-row configuration with Pin 1 index marker, and includes an exposed source pad (Pin 5) for thermal conduction. These dimensions are standardized in the Package Outline drawing on page 10 of the datasheet.