NXP Semiconductors BF1101WR,135

Overview

BF1101WR from NXP Semiconductors is an enhancement-type N-channel dual-gate MOSFET with source and substrate internally connected, designed for VHF/UHF RF amplification up to 1 GHz. It delivers 30 mS typical forward transfer admittance, 2.2 pF input capacitance at gate 1, and 1.7 dB noise figure at 800 MHz - enabling low-noise gain-controlled amplifier stages in TV tuners and professional communications equipment.

For engineers reviewing the BF1101WR datasheet, BF1101WR pinout, BF1101WR application, or BF1101WR equivalent, this page provides verified package mapping (SOT343R), validated pin functions, confirmed RF performance metrics (yfs, F, Crss), AGC-compatible self-biasing behavior, and real-world cross-modulation performance at 40 dB AGC.

Technical Context

The BF1101WR features two independent gates (G1 and G2) with distinct threshold voltages (VG1-S(th): 0.3–1.0 V; VG2-S(th): 0.3–1.2 V) and integrated protection diodes between each gate and source. Its internal self-biasing circuit ensures stable DC operation and maintains cross-modulation performance under automatic gain control (AGC) conditions.

It operates with a 3–7 V supply, supports 12 mA typical drain current at VDS = 5 V and VG2-S = 4 V, and exhibits pulsed yfs of 25–40 mS. The device is optimized for common-source configuration with low reverse transfer capacitance (Crss: 25–35 fF) and high input impedance at gate 2 (IG2-SS ≤ 20 nA).

Key Specifications

Pinout & Package

The BF1101WR is housed in the SOT343R plastic surface-mounted package (4 leads, reverse pinning), measuring 2.2 × 1.35 × 0.9 mm with 0.5 mm lead pitch. This compact outline supports high-density RF board layouts while maintaining thermal resistance R_{th j-s} = 200 K/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BF1101WR, BF1101R and BF1101 share identical RF parameters (yfs, F, Xmod, Crss) and bias characteristics but differ solely in package outline and pin numbering - making them functionally interchangeable only after PCB layout adaptation.

Availability

BF1101WR is available at Aetrix Electronics and suitable for television tuner front-ends, UHF professional transceivers, and RF signal generator output stages requiring stable component supply, consistent RF performance, and long-term obsolescence management.

Supply support for BF1101WR 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 communications, automotive, and industrial markets.

The BF1101WR belongs to NXP's legacy dual-gate MOSFET product line, engineered specifically for low-noise, AGC-stable VHF/UHF amplifier applications in broadcast and professional radio equipment.

FAQ

What is the maximum drain-source voltage rating for the BF1101WR?

The BF1101WR has a maximum drain-source voltage (V_DS) rating of 7 V, as specified in the Absolute Maximum Ratings table. This value defines the upper limit for safe DC bias and peak RF swing in amplifier designs. Exceeding 7 V risks permanent breakdown of the channel, especially under transient or mismatched load conditions. The BF1101WR is intended for low-voltage RF applications such as TV tuners and portable radios, not high-power switching circuits.

Does the BF1101WR require external biasing components for basic operation?

The BF1101WR incorporates a partly internal self-biasing circuit that stabilizes the DC operating point, particularly during AGC modulation. However, external resistors (e.g., RG1 = 120 kΩ to VGG) are required to set gate 1 bias voltage and achieve target drain current (e.g., 12 mA). Gate 2 is typically DC-biased at 4 V for optimal noise and gain performance. No external gate protection diodes are needed due to integrated G1–S and G2–S diodes.

How does the BF1101WR perform in terms of noise figure at UHF frequencies?

The BF1101WR achieves a typical noise figure (F) of 1.7 dB at 800 MHz under standard test conditions (V_DS = 5 V, V_G2-S = 4 V, I_D = 12 mA, Y_S = Y_{S opt}). This value is confirmed in the Dynamic Characteristics section and supported by scattering parameter data up to 1 GHz. Its low Crss (25–35 fF) and high yfs/C_ig1-ss ratio contribute to this performance, making the BF1101WR suitable for sensitive UHF receiver front-ends where noise minimization is critical.

What is the pin configuration of the BF1101WR and how does it differ from BF1101R?

The BF1101WR uses the SOT343R package with reverse pinning: Pin 1 = Drain, Pin 2 = Source, Pin 4 = Gate 2, Pin 3 = Gate 1. In contrast, the BF1101R (SOT143R) has Pin 1 = Source, Pin 2 = Drain, Pin 4 = Gate 1, Pin 3 = Gate 2. Although both are "reverse" variants, their pin numbering and physical layout differ - BF1101WR is smaller (2.2 × 1.35 mm) and not mechanically or electrically pin-compatible with BF1101R. PCB redesign is required for substitution.

Can the BF1101WR be used in automotive applications?

No - the BF1101WR is not automotive-qualified. Per NXP's disclaimers, unless explicitly stated in the datasheet, the device is not tested or warranted for automotive use. It lacks AEC-Q200 qualification, extended temperature validation beyond 150 °C junction, or automotive-grade reliability screening. For automotive infotainment tuners or telematics receivers, designers must select NXP's officially qualified alternatives or perform full application-level validation at their own risk.