NXP Semiconductors BFU550R

Overview

BFU550R from NXP Semiconductors is an AEC-Q101 qualified NPN silicon RF transistor in SOT143B package, designed for low-noise, high-gain amplification up to 2 GHz. It delivers 0.7 dB NFmin at 900 MHz, 21 dB maximum stable gain, 11 GHz fT, and supports 24 V collector-base voltage with dual-emitter configuration for broadband ISM band applications.

For engineers reviewing the BFU550R datasheet, BFU550R pinout, BFU550R application, or BFU550R equivalent, this page provides verified technical context, pin-level circuit roles, real-world LNA performance data at 433/866 MHz, thermal derating curves, and validated alternative transistors for RF front-end design.

Technical Context

The BFU550R operates as a high-frequency small-signal amplifier with dual-emitter topology enabling emitter degeneration for stability and noise optimization. Its 11 GHz fT and 0.72 pF collector capacitance support wideband operation from 433 MHz to 1.8 GHz while maintaining sub-1 dB noise figure under ΓS = Γopt matching.

It employs silicon bipolar technology with AEC-Q101 qualification, supporting junction temperatures up to +150 °C and featuring 140 K/W junction-to-solder-point thermal resistance. The device is optimized for fixed-bias or emitter-degenerated configurations in low-noise amplifier stages requiring high breakdown voltage (V_CEO = 12 V, V_CBO = 24 V).

Key Specifications

Pinout & Package

Package: SOT143B - plastic surface-mounted, 4-lead dual-emitter package with exposed collector pad for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BFU520 and BFU530, the BFU550R offers the highest fT and lowest noise figure in the BFU5 family, making it optimal for demanding 1.8 GHz ISM applications where gain-bandwidth product and noise floor are critical.

Availability

BFU550R is available at Aetrix Electronics and suitable for 433 MHz ISM band LNAs, 866 MHz SRD receivers, and broadband RF driver stages requiring stable component supply across automotive, industrial, and wireless infrastructure programs.

Supply support for BFU550R 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 secure connectivity solutions for automotive, industrial, and IoT markets.

The BFU550R belongs to NXP's BFU5 family of high-performance RF transistors, engineered specifically for low-noise, high-breakdown-voltage amplifier and oscillator applications in ISM bands up to 2 GHz.

FAQ

What is the minimum noise figure of the BFU550R and under what conditions is it achieved?

The BFU550R achieves a minimum noise figure of 0.7 dB at 900 MHz when biased at IC = 1 mA, VCE = 8 V, and matched to its optimum source reflection coefficient (ΓS = Γopt). This value is confirmed in Table 1 of the official NXP datasheet Rev. 2.1. The BFU550R maintains sub-1.3 dB NF across 433–1800 MHz in practical LNA implementations, as validated in application notes AN11431 and AN11432.

Is the BFU550R pin-compatible with other devices in the BFU5 family?

Yes, the BFU550R shares the identical SOT143B package and 4-pin pinout (collector, base, emitter, emitter) with BFU520 and BFU530. All three devices use the same mechanical footprint and thermal pad layout, enabling drop-in replacement in existing PCB designs without layout changes. However, biasing networks may require adjustment due to differing optimal IC points.

What is the maximum collector-emitter voltage rating for the BFU550R?

The BFU550R has a maximum collector-emitter voltage (V_CEO) rating of 12 V under shorted-base conditions, as specified in Table 6 (Limiting Values) and Table 9 (Characteristics) of the NXP datasheet. This rating ensures safe operation in 3.3 V and 5 V RF supply rails with margin for transient spikes and RF peak swing.

Does the BFU550R support operation at 1800 MHz, and what gain can be expected?

Yes, the BFU550R supports operation at 1800 MHz with verified performance: Gp(max) = 15 dB and |s21|² = 12 dB at IC = 25 mA, VCE = 8 V (Figure 11 and Table 9). Application data shows 19.5 dBm P1dB output power at 1800 MHz, confirming usability in 1.8 GHz ISM and LTE band edge applications.

What thermal considerations apply when using the BFU550R in continuous operation?

The BFU550R has a thermal resistance Rth(j-sp) of 140 K/W from junction to solder point. To maintain Tj ≤ 150 °C, the solder point temperature (Tsp) must stay ≤ 87 °C at full 450 mW dissipation. Derating is required above 87 °C per Figure 1 - e.g., at Tsp = 100 °C, maximum allowable Ptot drops to ~380 mW.