NXP Semiconductors BFS17,215

Overview

BFS17,215 from NXP Semiconductors is an NPN silicon RF transistor in SOT23 package, rated for 1 GHz transition frequency (f_T), 15 V V_CEO, 25 mA I_C, and 4.5 dB noise figure at 500 MHz - optimized for mixer and oscillator stages in TV tuners and RF communications equipment.

For engineers reviewing the BFS17,215 datasheet, BFS17,215 pinout, BFS17,215 application, or BFS17,215 equivalent, key selection criteria include its 1.6 GHz f_T at 25 mA, low 0.8–1.5 pF collector capacitance, SOT23 thermal resistance of 260 K/W, and verified performance in 50 Ω impedance-matched RF front-ends.

Technical Context

The BFS17,215 operates as a high-frequency NPN bipolar junction transistor with DC current gain (h_FE) of 25–90 across 2–25 mA collector current. Its f_T reaches 1.6 GHz under 25 mA/5 V conditions, enabling stable small-signal amplification up to UHF bands.

Designed for narrow-base, low-capacitance operation, it delivers 4.5 dB noise figure at 500 MHz with 50 Ω source impedance and exhibits collector capacitance (C_c) of 0.8–1.5 pF and feedback capacitance (C_re) of 0.65 pF - critical for oscillator phase noise and mixer port isolation.

Key Specifications

Pinout & Package

Package: SOT23 (TO-236AB), plastic surface-mounted, 3-lead, marking code E1p. Dimensions per IEC/JEDEC outline: D = 2.8 mm, E = 1.4 mm, Lp = 1.2 mm, e = 1.9 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BF199,215 and MPSH10RLRA, the BFS17,215 uniquely balances 1.6 GHz f_T, 4.5 dB NF, and SOT23 thermal performance - making it the preferred choice for compact, high-SNR UHF mixer and oscillator circuits where layout space and noise floor are constrained.

Availability

BFS17,215 is available at Aetrix Electronics and suitable for TV tuner design, portable radio front-ends, and ISM-band transceiver development requiring stable component supply and long-term obsolescence management.

Supply support for BFS17,215 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 leader specializing in high-performance RF, analog, and mixed-signal solutions for automotive, industrial, and consumer applications.

The BFS17,215 belongs to NXP's legacy discrete RF transistor family, engineered specifically for cost-sensitive, space-constrained UHF signal processing in broadcast and communications equipment.

FAQ

What is the maximum operating frequency supported by the BFS17,215?

The BFS17,215 has a transition frequency (f_T) of 1.6 GHz at I_C = 25 mA and V_CE = 5 V, meaning it can provide useful small-signal gain up to approximately 800–1000 MHz in practical amplifier and mixer designs. Its 1 GHz wideband specification reflects guaranteed performance across the UHF broadcast band (470–862 MHz) with margin for aging and process variation.

Does the BFS17,215 require external neutralization in oscillator applications?

The BFS17,215 features low feedback capacitance (C_re = 0.65 pF), reducing the need for neutralization in Colpitts or Clapp oscillator topologies operating below 1 GHz. However, for high-stability 800+ MHz oscillators, a small series inductor (1–3 nH) in the base lead is recommended to suppress potential parasitic resonance without full neutralization circuitry.

What is the thermal resistance from junction to solder point for the BFS17,215?

The BFS17,215 has a thermal resistance R_{th j-s} of 260 K/W, measured from junction to the soldering point of the collector pin (Ts). This value assumes PCB mounting with standard SOT23 pad layout and defines the temperature rise under 300 mW total dissipation - critical for reliability in sealed tuner modules with limited airflow.

Can the BFS17,215 be used in common-base configuration for RF amplification?

Yes, the BFS17,215 is routinely used in common-base mode for broadband RF amplification, especially in TV tuner IF strips. With emitter as input and collector as output, its low input impedance (~50 Ω at 500 MHz) and high reverse isolation (due to C_re = 0.65 pF) make it ideal for cascode driver stages where stability and wideband response are prioritized over voltage gain.

What is the typical noise figure of the BFS17,215 at 100 MHz?

The BFS17,215 datasheet specifies noise figure only at 500 MHz (4.5 dB typ), with no published data at 100 MHz. Extrapolation is unreliable due to strong frequency dependence of bipolar transistor noise mechanisms; actual NF at 100 MHz would likely be <3.5 dB but must be measured in-circuit with proper 50 Ω matching and bias conditions - the BFS17,215 is not characterized or guaranteed for sub-400 MHz low-noise operation.