NXP Semiconductors BF1105R,215

Overview

BF1105R,215 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 tuner front-ends. It delivers 31 mS typical forward transfer admittance, 2.2 pF input capacitance at gate 1, and 1.7 dB typical noise figure at 800 MHz under 5 V supply - enabling high-gain, low-distortion signal amplification in television tuners and professional communications receivers.

For engineers reviewing the BF1105R,215 datasheet, BF1105R,215 pinout, BF1105R,215 application, or BF1105R,215 equivalent, key selection considerations include its SOT143R reverse-pin package, self-biasing capability for AGC-stable operation, dual-gate architecture for gain control, and verified cross-modulation performance up to 100 dBµV at 40 dB AGC.

Technical Context

The BF1105R,215 implements a short-channel dual-gate structure with integrated protection diodes between each gate and source, ensuring robustness against input voltage surges. Its internal self-biasing circuit establishes stable DC operating point (8–16 mA drain current at VG2-S = 4 V), critical for consistent cross-modulation performance during automatic gain control.

As a common-source RF amplifier, it operates with VG2-S fixed at 4 V and VG1-S as the signal input, delivering 38 dB power gain at 200 MHz and 20 dB at 800 MHz. The device's low Crss (25–40 fF) and optimized yfs/Cig1 ratio support wideband amplification up to 1 GHz with minimal feedback-induced instability.

Key Specifications

Pinout & Package

SOT143R plastic surface-mounted package (reverse pinning), 4-lead, dimensions: D = 2.8–3.0 mm, E = 1.2–1.4 mm, A = 0.9–1.1 mm, bp = 0.38–0.48 mm. Pin 1 = source, Pin 2 = drain, Pin 4 = gate 2, Pin 3 = gate 1 (top view: 1–2–4–3).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BF1105,215 and BF1105WR,215, the BF1105R,215 offers identical RF performance and self-biasing behavior but occupies the SOT143R package - balancing compactness, manufacturability, and thermal capability for mainstream VHF/UHF tuner production.

Availability

BF1105R,215 is available at Aetrix Electronics and suitable for television tuner front-ends, professional UHF receivers, and VHF communications transceivers requiring stable component supply across long-lifecycle consumer and industrial programs.

Supply support for BF1105R,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 specializing in high-performance RF, analog, and mixed-signal solutions for connectivity, sensing, and power management.

The BF1105R,215 belongs to NXP's legacy dual-gate MOSFET product line, engineered specifically for low-noise, high-gain RF amplification in VHF/UHF tuner and receiver applications with 5 V supply constraints.

FAQ

What is the maximum drain-source voltage rating for BF1105R,215?

The BF1105R,215 has a maximum drain-source voltage (VDS) rating of 7 V, as defined in its Absolute Maximum Ratings table. This limit applies under all operating conditions and must not be exceeded to prevent permanent device damage. In practice, the BF1105R,215 is typically operated at 5 V supply in VHF/UHF tuner applications, leaving 2 V of safe margin below the 7 V absolute maximum. Exceeding this rating risks avalanche breakdown and irreversible degradation of the N-channel channel.

How does the self-biasing circuit in BF1105R,215 function?

The BF1105R,215 incorporates an internal self-biasing circuit that establishes a stable DC operating point without external resistors. When gate 2 is biased at 4 V, the device draws 8–16 mA drain current (IDSX), automatically setting gate 1 at the appropriate DC potential for linear RF amplification. This feature ensures consistent cross-modulation performance during AGC operation and eliminates the need for discrete bias networks - simplifying tuner design and improving thermal stability across temperature ranges.

What is the pin configuration of BF1105R,215 in the SOT143R package?

The BF1105R,215 uses the SOT143R package with reverse pinning: Pin 1 = source, Pin 2 = drain, Pin 4 = gate 2, Pin 3 = gate 1 (top view reading left-to-right as 1–2–4–3). This differs from the standard SOT143B used by BF1105,215 (1–2–3–4). The reverse arrangement places gate 2 adjacent to the drain for optimized high-frequency layout - critical for minimizing parasitic inductance in VHF/UHF amplifier matching networks.

Can BF1105R,215 be used in automotive applications?

No, the BF1105R,215 is not automotive-qualified. Per NXP's product disclaimer, unless explicitly stated in the datasheet, the device is not tested or warranted for automotive use. It lacks AEC-Q100 qualification, automotive-grade temperature screening (−40 °C to +125 °C extended range), and reliability validation for vibration, humidity, and lifetime stress profiles required in vehicle systems. Use in automotive applications is at the customer's sole risk and voids NXP's standard warranty.

What is the typical noise figure of BF1105R,215 and at what frequency is it measured?

The BF1105R,215 has a typical noise figure (F) of 1.7 dB, measured at 800 MHz with YS = YS opt (optimum source admittance), VDS = 5 V, VG2-S = 4 V, and ID = 12 mA. This value reflects its performance as a low-noise amplifier in UHF bands and is validated in the device's Dynamic Characteristics section. The noise figure remains ≤2.5 dB across the 800 MHz condition, confirming suitability for high-sensitivity receiver front-ends where signal-to-noise ratio is critical.