NXP Semiconductors BF909A,215

Overview

BF909A,215 from NXP Semiconductors is an N-channel dual-gate MOSFET designed for low-noise VHF/UHF amplifier stages in 3–7 V supply systems. It delivers 43 mS typical forward transfer admittance, 3.6 pF input capacitance at gate 1, and 2.0 dB minimum noise figure at 800 MHz - enabling high-gain, low-distortion signal amplification in TV tuners and professional RF receivers.

For engineers reviewing the BF909A,215 datasheet, BF909A,215 pinout, BF909A,215 application, or BF909A,215 equivalent, this page provides verified package mapping (SOT143), confirmed dual-gate biasing behavior, cross-modulation performance data at 50 MHz, and real-world AGC-stable operation up to 1 GHz - all critical for RF front-end design validation and tuner module replacement.

Technical Context

This device integrates two cascaded MOSFET gates (G1 and G2) with internal substrate-source connection, enabling independent gain control and superior AGC linearity. Its short-channel structure yields high |y_fs|/C_ig1-s ratio (≥11.9 mS/pF), directly supporting wideband low-noise amplification without external bias networks.

Designed specifically for 5 V operation, the BF909A,215 features gate threshold voltages of 0.3–1.0 V (G1) and 0.3–1.2 V (G2), with gate leakage <50 nA at 5 V - ensuring stable DC bias under varying temperature and supply conditions in compact tuner modules.

Key Specifications

Pinout & Package

BF909A,215 is housed in a plastic microminiature SOT143 package (3.0 × 1.4 × 0.95 mm), optimized for high-frequency layout with minimal parasitic inductance. The leadframe design supports reflow soldering and provides thermal resistance R_{th j-a} = 500 K/W when mounted on PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BF909A,215, BF998,215 trades 0.5 dB noise penalty for +12 mS gain and narrower input capacitance - making it preferable in wideband gain-critical links. MRF901T1 serves entirely different system roles: it lacks dual-gate AGC and cannot replace BF909A,215 in low-noise receive chains.

Availability

BF909A,215 is available at Aetrix Electronics and suitable for television tuner modules, professional UHF receivers, CATV drop amplifiers, and wireless microphone front-ends requiring stable component supply across extended production lifecycles.

Supply support for BF909A,215 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 high-performance analog, RF, and mixed-signal solutions for automotive, industrial, and consumer markets.

The BF909A,215 belongs to NXP's legacy RF transistor portfolio, engineered specifically for VHF/UHF low-noise amplification in broadcast and communications equipment - emphasizing AGC stability, thermal resilience, and 5 V compatibility.

FAQ

What is the maximum drain-source voltage rating for BF909A,215?

The BF909A,215 has a maximum drain-source voltage (V_DS) rating of 7 V, as defined in its Absolute Maximum Ratings table. This rating applies under all operating conditions and ensures safe operation with standard 5 V supply rails plus transient margin. Exceeding 7 V risks permanent damage per IEC 60134 limiting values. The BF909A,215 is not rated for 12 V or higher rail applications.

Does BF909A,215 require external bias resistors for gate 1 and gate 2?

Yes, the BF909A,215 requires external biasing: gate 2 (pin 3) is typically held at 4 V via a voltage divider or regulator, while gate 1 (pin 4) connects to the RF input through a high-impedance path - often with a 120 kΩ resistor (RG1) to V_GG. The internal bias circuit only ensures cross-modulation performance during AGC; it does not eliminate need for external DC bias networks.

What is the typical noise figure of BF909A,215 and at what frequency is it measured?

The BF909A,215 achieves a minimum noise figure (F) of 2.0 dB at 800 MHz, measured under standard conditions: V_DS = 5 V, V_G2-S = 4 V, I_D = 15 mA, with source and load impedances tuned to Γ_opt = 0.603∠67.7°. This value is confirmed in Table 2 of the official NXP datasheet and reflects its suitability for UHF receiver front-ends.

Can BF909A,215 be used in 3 V supply applications?

The BF909A,215 is characterized and optimized for 5 V operation, but functional operation down to 3 V is possible with reduced performance: |y_fs| drops ~25%, noise figure increases by ~0.8 dB, and cross-modulation suppression degrades. NXP does not guarantee specifications below 4 V; for true 3 V designs, consider purpose-built low-voltage alternatives like BF1108.

What package type is used for BF909A,215 and is it RoHS compliant?

The BF909A,215 uses the SOT143 plastic microminiature package (3.0 × 1.4 × 0.95 mm), as confirmed in Figures 19 and 20 of the NXP datasheet. While the original 2007 datasheet predates full RoHS enforcement, NXP confirms SOT143-packaged BF909 variants - including BF909A,215 - were transitioned to lead-free assembly prior to 2010 and meet RoHS Directive 2011/65/EU with homogeneous lead content <1000 ppm.