NXP Semiconductors BF245B,112

Overview

BF245B,112 from NXP Semiconductors is a general-purpose N-channel symmetrical junction field-effect transistor (JFET) in a plastic TO-92 variant (SOT54) package, rated for ±30 V drain-source voltage, 6–15 mA zero-gate drain current (IDSS), and 700 MHz cut-off frequency (fgfs). It operates as a low-noise RF/AF amplifier device with interchangeable drain and source terminals, commonly used in HF receiver front-ends and audio preamplifier stages.

For engineers reviewing the BF245B,112 datasheet, BF245B,112 pinout, BF245B,112 application, or BF245B,112 equivalent, key selection criteria include gate-source cut-off voltage range (−1.6 V to −3.8 V), forward transfer admittance (3–6.5 mS), reverse transfer capacitance (1.1 pF), thermal resistance (250 K/W), and compatibility with through-hole PCB layouts requiring symmetrical JFET biasing.

Technical Context

The BF245B,112 employs a symmetrical N-channel junction structure enabling bidirectional operation-drain and source terminals are functionally interchangeable under DC and small-signal AC conditions. Its transconductance profile supports stable self-biasing in common-source configurations without external gate resistors in many linear amplification applications.

Designed for frequencies up to 700 MHz, it delivers low noise figure (1.5 dB at 100 MHz) and minimal reverse transfer capacitance (1.1 pF), making it suitable for tuned RF amplifiers where feedback control and gain stability are critical. Static characteristics are specified at Tj = 25 °C with pulse testing (tp = 300 µs, δ ≤ 0.02) to avoid thermal drift during measurement.

Key Specifications

Pinout & Package

BF245B,112 is housed in a plastic single-ended leaded (through-hole) TO-92 variant package designated SOT54, with 3 leads arranged on-circle. The package outline conforms to IEC/JEDEC standards, featuring 2.54 mm lead pitch (e), 5.2 mm body length (A), and 4.8 mm body width (D).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar JFET amplifier applications.

Compared with J310 and 2N5457, BF245B,112 offers balanced IDSS and VGSoff for stable HF amplification with proven 1.5 dB noise figure at 100 MHz-making it preferable for receiver front-ends where gain consistency and RF linearity outweigh compactness or ultra-low bias current.

Availability

BF245B,112 is available at Aetrix Electronics and suitable for HF receiver front-ends, audio preamplifier stages, and DC-coupled instrumentation amplifiers requiring stable component supply and long-term obsolescence management.

Supply support for BF245B,112 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 delivering high-performance mixed-signal and standard product solutions, with leadership in RF, analog, power management, and interface technologies.

The BF245B,112 belongs to NXP's legacy discrete JFET family designed for general-purpose analog signal conditioning-optimized for reliability, manufacturability, and consistent parametric distribution across HF, AF, and DC applications.

FAQ

What is the maximum drain-source voltage rating for BF245B,112?

The BF245B,112 has a maximum drain-source voltage (VDS) rating of ±30 V, as defined in the Absolute Maximum Ratings table. This rating applies under all operating conditions and must not be exceeded to prevent permanent device damage. Derating is recommended above Tamb = 75 °C per the thermal resistance specification of 250 K/W.

Does BF245B,112 support interchangeable drain and source connections in circuit design?

Yes, BF245B,112 features a symmetrical N-channel junction structure that allows functional interchangeability of drain and source terminals in both DC biasing and small-signal AC operation. This is explicitly confirmed in the Features section of the datasheet and enables flexible topology choices such as common-source or common-drain configurations without altering component placement.

What is the typical noise figure of BF245B,112 and at what frequency is it measured?

The typical noise figure of BF245B,112 is 1.5 dB, measured at 100 MHz under common-source configuration with VDS = 15 V, VGS = 0 V, RG = 1 kΩ, and input tuned for minimum noise. This value is specified in the Dynamic Characteristics section and reflects its suitability for low-noise HF amplifier applications.

What package type is used for BF245B,112 and what are its key mechanical dimensions?

BF245B,112 uses the SOT54 variant-a plastic TO-92 through-hole package with 3 leads on-circle. Key dimensions include 2.54 mm lead pitch (e), 5.2 mm body length (A), 4.8 mm body width (D), and 14.5 mm overall length (L). Minimum 3 mm lead length and 10 mm × 10 mm drain pad are required for thermal compliance per datasheet note.

How does BF245B,112 differ from BF245A and BF245C in terms of drain current and cut-off voltage?

BF245B,112 has IDSS of 6–15 mA and VGSoff of −1.6 to −3.8 V, positioning it between BF245A (IDSS = 2–6.5 mA, VGSoff = −0.25 to −2.2 V) and BF245C (IDSS = 12–25 mA, VGSoff = −3.2 to −7.5 V). This mid-range specification provides balanced gain, bias stability, and noise performance for general-purpose amplification where extreme low-current or high-current operation is unnecessary.