NXP Semiconductors BFS17W,135

Overview

BFS17W from NXP Semiconductors is a silicon NPN wideband RF transistor in SOT323 (SC-70) package, designed for high-frequency signal processing with 1.6 GHz transition frequency (f_T), 0.8–1.5 pF collector capacitance (C_c), and 4.5 dB noise figure at 500 MHz - primarily deployed in UHF/VHF tuner mixer, oscillator, and IF amplifier stages.

For engineers reviewing the BFS17W datasheet, BFS17W pinout, BFS17W application, or BFS17W equivalent, key selection considerations include its 15 V V_CEO, 50 mA I_C, 300 mW P_tot, low feedback capacitance (0.75 pF C_re), and thermal resistance of 190 K/W - critical for stable RF gain and noise performance in compact tuner front-ends.

Technical Context

The BFS17W employs a planar epitaxial silicon NPN structure optimized for wideband RF operation up to 1 GHz, with f_T = 1.6 GHz measured at I_C = 25 mA and V_CE = 5 V. Its low C_c (0.8–1.5 pF) and C_re (0.75 pF) minimize unwanted coupling and improve stability in oscillator and mixer configurations.

Designed for UHF/VHF tuner signal chains, it operates with DC bias conditions supporting 2–25 mA collector current and delivers h_FE = 25–90 at I_C = 2 mA/V_CE = 1 V. The SOT323 package enables surface-mount integration while maintaining thermal performance via 190 K/W junction-to-solder-point resistance.

Key Specifications

Pinout & Package

Package: SOT323 (SC-70), plastic surface-mounted, 3-lead miniature package with 0.65 mm lead pitch and 1.3 × 1.8 mm body size.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN wideband RF transistor applications.

Compared with BFS17,115 and MRF901LT1G, the BFS17W offers optimal balance of UHF gain, noise, and thermal performance in the smallest standard RF package - making it preferred for space-constrained tuner IF and mixer designs where SOT323 layout compatibility is required.

Availability

BFS17W is available at Aetrix Electronics and suitable for UHF/VHF tuners, FM radio front-ends, and set-top box signal paths requiring stable component supply, consistent RF performance, and long-term obsolescence management.

Supply support for BFS17W 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 consumer, industrial, and communications markets.

The BFS17W belongs to NXP's legacy discrete RF transistor family, engineered specifically for broadcast tuner applications demanding low-noise, wideband amplification and oscillation in compact surface-mount packages.

FAQ

What is the maximum operating frequency of the BFS17W?

The BFS17W has a typical transition frequency (f_T) of 1.6 GHz at I_C = 25 mA and V_CE = 5 V, enabling reliable operation as an amplifier or oscillator up to 1 GHz. Its low feedback capacitance (0.75 pF) and 0.8–1.5 pF collector capacitance support stable gain in UHF tuner circuits. The BFS17W is not rated for continuous operation beyond its f_T limit, and system-level bandwidth depends on external matching networks.

Can the BFS17W replace the BFS17 in an existing design?

Yes, the BFS17W uses the same silicon die as the BFS17 but is packaged in SOT323 instead of SOT23. Electrical characteristics including f_T, h_FE, C_c, and noise figure are identical per NXP's datasheet. However, the BFS17W requires a different PCB footprint and thermal pad layout due to its smaller 0.65 mm lead pitch and 1.3 × 1.8 mm body - so board rework is needed for direct substitution.

What is the recommended bias condition for BFS17W in oscillator applications?

For Colpitts or Clapp oscillator designs, NXP recommends I_C = 2–5 mA with V_CE = 5–8 V and base bias set to achieve h_FE-dependent loop gain. The BFS17W's h_FE range (25–90 at I_C = 2 mA) supports stable start-up across temperature; emitter degeneration and collector tank Q must be tuned to suppress spurious modes. The BFS17W's low C_re helps maintain phase margin in high-Q resonant tanks.

Does the BFS17W have automotive qualification?

No, the BFS17W is not automotive-qualified. Per NXP's datasheet disclaimers, it is classified as a non-automotive product and has not been tested or qualified to AEC-Q101 or other automotive reliability standards. It is intended for consumer broadcast equipment such as TV tuners and FM radios. For automotive infotainment tuner modules, designers must perform independent qualification testing and assume full responsibility for field reliability of the BFS17W.

How does thermal management affect BFS17W performance in continuous RF operation?

The BFS17W's R_{th j-s} is 190 K/W, meaning junction temperature rises ~190 °C per watt above the solder point. At its 300 mW P_tot rating, even modest RF drive can push T_j near 175 °C if PCB copper area is insufficient. Derating curves show usable power drops sharply above 118 °C solder point temperature. Proper thermal pad design and ground plane coupling are essential to sustain BFS17W gain and noise performance over time.