Nexperia USA Inc. BFS20W,115

Overview

BFS20W from Nexperia is an NPN medium-frequency transistor in SOT323 (SC-70) package, designed for IF and VHF amplification stages in thick/thin-film circuits. It features a maximum collector-emitter voltage of 20 V, DC current gain (h_FE) of 40–85 at 7 mA/10 V, transition frequency (f_T) of 360–470 MHz, and ultra-low feedback capacitance of 350 fF - enabling stable high-frequency operation in compact RF front-ends.

For engineers reviewing the BFS20W datasheet, BFS20W pinout, BFS20W application, or BFS20W equivalent, this device is selected for low-noise, low-power VHF amplifier stages where thermal efficiency, minimal parasitic capacitance, and consistent gain across temperature are critical - especially in space-constrained consumer and industrial RF modules.

Technical Context

The BFS20W operates as a general-purpose NPN RF transistor optimized for medium-frequency signal amplification up to ~500 MHz. Its low V_CEO (20 V) and I_C (25 mA) rating reflect its role in low-voltage, low-current RF gain blocks rather than power switching or broadband driver stages.

Thermal resistance (R_{th j-a}) is 625 K/W under standard SOT323 mounting, indicating limited power handling but sufficient for bias-stable small-signal amplifiers. The 350 fF feedback capacitance (C_re) and 1 pF collector capacitance (C_c) minimize Miller effect, supporting predictable gain roll-off and stability in tuned amplifier designs.

Key Specifications

Pinout & Package

SOT323 (SC-70) plastic surface-mount package: 1.35 mm × 1.75 mm × 0.95 mm body, 3-terminal leadless outline with gull-wing leads; thermally efficient for low-power RF use with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN medium-frequency transistor applications.

Compared with BC847BW and MMBT2222ALT1G, the BFS20W uniquely balances ultra-low C_re, verified VHF f_T, and tight thermal profile in SOT323 - making it optimal for miniaturized, temperature-stable IF/VHF amplifiers where feedback control and layout density are prioritized over raw gain or voltage headroom.

Availability

BFS20W is available at Aetrix Electronics and suitable for FM radio IF amplifiers, TV tuner front-ends, wireless microphone preamps, and ISM-band sensor transmitters requiring stable component supply across industrial and consumer production cycles.

Supply support for BFS20W 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

Nexperia is a global leader in discrete, logic, and PowerMOS semiconductors, formed in 2017 from the former NXP Standard Products division, with focus on automotive, industrial, computing, and consumer markets.

The BFS20W belongs to Nexperia's legacy RF transistor product line, engineered specifically for medium-frequency amplification in space-constrained, cost-sensitive RF modules where reliability, consistency, and proven VHF behavior are essential.

FAQ

Is BFS20W suitable for 433 MHz ASK transmitter output stages?

Yes - its 360–470 MHz f_T, 350 fF C_re, and 20 V V_CEO support clean amplification at 433 MHz with proper matching and biasing. Measured VCEsat < 100 mV at IC = 10 mA confirms low-loss switching capability for OOK/ASK modulation, provided thermal design respects 200 mW P_tot derating above 25 °C.

What is the recommended PCB layout practice for BFS20W in VHF applications?

Use short, direct traces for base/emitter/collector connections; place ground plane beneath the SOT323 footprint with minimal clearance; avoid vias in RF paths; implement collector load as chip inductor + capacitor LC tank with shielded routing. Thermal relief for the collector pad improves heat dissipation without compromising RF return path integrity.

Does BFS20W have qualified automotive-grade variants?

No - the BFS20W is not AEC-Q101 qualified. Nexperia offers automotive-qualified alternatives like the PBSS4041T (SOT323, 40 V, f_T = 250 MHz) for similar topologies, but BFS20W remains a commercial-grade part intended for consumer, industrial, and computing applications per its original NXP product data sheet status.

Can BFS20W replace BFS17 in existing designs?

Not directly - BFS17 has higher V_CEO (30 V), higher f_T (650 MHz), and different pinout (TO-18 metal can). While both are NPN RF transistors, BFS20W's lower voltage rating and SOT323 package require PCB redesign and bias recalculations. Use only after verifying gain, stability, and thermal margins at target frequency and supply conditions.