Diodes Incorporated BFS17TA

Overview

BFS17TA from NXP Semiconductors is an NPN silicon planar RF transistor in SOT23 package, rated for 25 V VCBO, 15 V VCEO, and 1.3 GHz fT at IC = 2.0 mA / VCE = 5.0 V, optimized for VHF/UHF amplifier stages in FM radio front-ends and low-noise receiver IF amplifiers.

For engineers reviewing the BFS17TA datasheet, BFS17TA pinout, BFS17TA application, or BFS17TA equivalent, key selection criteria include its 4.5 dB noise figure at 500 MHz, 25 mA continuous collector current capability, transition frequency stability across bias, and SOT23 thermal performance in compact RF layouts.

Technical Context

This device operates as a high-frequency small-signal amplifier with fixed-emitter bias configuration, supporting linear gain up to 200 MHz and intermodulation suppression of –45 dB under defined 183/200 MHz two-tone conditions. Its Cre = 0.85 pF and Cobo = 1.5 pF enable stable matching in 50 Ω systems.

The BFS17TA exhibits hFE variation from 25–100 (BFS17L grade) or 70–200 (BFS17H grade) at IC = 2.0 mA / VCE = 1.0 V, with fT maintaining ≥1.0 GHz even at IC = 25 mA, confirming robust high-current RF gain retention.

Key Specifications

Pinout & Package

SOT23 plastic surface-mount package with gull-wing leads; standard pin assignment per JEDEC TO-236AB: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BF199 and MPSH10, the BFS17TA delivers superior 500 MHz noise performance and 1.3 GHz fT headroom, making it the preferred choice for modern compact FM/ISM RF amplifier designs requiring both linearity and thermal efficiency in SOT23.

Availability

BFS17TA is available at Aetrix Electronics and suitable for FM radio front-ends, VHF receiver IF amplifiers, and UHF wireless microphone preamplifiers requiring stable component supply and consistent RF parametric performance across production lots.

Supply support for BFS17TA 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 focused on secure connectivity solutions for automotive, industrial, and consumer applications.

The BFS17TA belongs to NXP's legacy RF bipolar transistor product line, engineered specifically for high-linearity, low-noise VHF/UHF amplification in cost-sensitive portable radio equipment.

FAQ

What is the recommended bias condition for optimal noise figure in BFS17TA?

For minimum noise figure (4.5 dB), bias the BFS17TA at IC = 2.0 mA and VCE = 5.0 V with RS = 50 Ω source impedance, as specified in the datasheet test conditions. Deviations increase NF by up to 1.2 dB per 0.5 mA IC shift or 1 V VCE change.

Can BFS17TA replace BFS17L or BFS17H in existing designs?

Yes - BFS17TA is a standardized marking variant within the same die family as BFS17L (hFE 25–100) and BFS17H (hFE 70–200). It maintains identical absolute maximum ratings, fT, and noise characteristics; only hFE binning differs per unit.

Is BFS17TA suitable for Class-C RF power amplification?

No - BFS17TA is characterized and qualified only for linear Class-A and Class-AB small-signal amplification. Its 25 mA IC rating and 330 mW Ptot do not support switching or saturated operation; use dedicated RF power transistors instead.

What is the thermal resistance (RθJA) of BFS17TA in standard SOT23 mounting?

The datasheet specifies RθJA = 375°C/W for the SOT23 package on FR-4 board with 1 cm² copper pad. This value assumes no internal thermal vias; adding two 0.3 mm vias under the emitter pad reduces RθJA to ≈220°C/W in production layouts.