Infineon Technologies BFR181E6327HTSA1

Overview

BFR181E6327HTSA1 from Infineon Technologies is a low-noise silicon bipolar RF transistor optimized for broadband amplifier stages in 900 MHz and 1.8 GHz cellular front-ends, featuring f_T = 8 GHz, NF_min = 0.9 dB at 900 MHz, and h_FE = 70–140 at I_C = 5 mA, V_CE = 8 V.

For engineers reviewing the BFR181E6327HTSA1 datasheet, BFR181E6327HTSA1 pinout, BFR181E6327HTSA1 application, or BFR181E6327HTSA1 equivalent, key selection criteria include noise figure vs. collector current trade-off, SOT23 thermal resistance (R_thJS = 335 K/W), and verified transducer gain of 14.5 dB at 900 MHz into 50 Ω.

Technical Context

This NPN RF transistor operates in common-emitter configuration with emitter-grounded biasing for low-noise amplification. Its f_T ≥ 6 GHz (typ. 8 GHz) and C_cb = 0.27 pF (typ.) support stable high-frequency gain up to 1.8 GHz while maintaining Z_Sopt-matched noise performance.

Designed for DC-coupled or AC-coupled small-signal amplification, it delivers G_ms = 18.5 dB (900 MHz) and G_ma = 12.5 dB (1.8 GHz) under matched source/load conditions, with validated |S₂₁|² = 14.5 dB at 900 MHz and 9.5 dB at 1.8 MHz (note: 1.8 MHz is typographical; context confirms 1.8 GHz).

Key Specifications

Pinout & Package

Package: SOT23 - surface-mount plastic package with gull-wing leads, RoHS-compliant, qualified per AEC-Q101.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BFR92A and MRF581, BFR181E6327HTSA1 uniquely balances 8 GHz f_T, 0.9 dB NF_min, and SOT23 thermal performance-making it optimal for space-constrained, dual-band 900/1800 MHz RF front-ends requiring AEC-Q101 compliance.

Availability

BFR181E6327HTSA1 is available at Aetrix Electronics and suitable for GSM/EDGE base station receivers, automotive telematics antenna modules, and portable RFID reader front-ends requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BFR181E6327HTSA1 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

Infineon Technologies AG is a German semiconductor manufacturer specializing in power management, RF, automotive, and security ICs, with global manufacturing and R&D centers.

The BFR181 belongs to Infineon's discrete RF transistor product line, engineered specifically for low-noise, high-gain amplification in sub-2 GHz wireless infrastructure and automotive connectivity systems.

FAQ

What is the recommended DC bias condition for minimum noise figure?

The datasheet specifies NF_min = 0.9 dB at I_C = 2 mA, V_CE = 8 V with source impedance Z_S = Z_Sopt. This condition requires external matching network synthesis using measured S-parameters; fixed-bias resistors alone will not achieve Z_Sopt without tuning.

Is BFR181E6327HTSA1 suitable for 5G NR sub-6 GHz bands?

No-its f_T = 8 GHz and verified gain at 1.8 GHz do not support reliable operation above 2.5 GHz. For n77/n78 bands (3.3–3.8 GHz), transistors with f_T > 25 GHz (e.g., BFP740F) are required to maintain gain and noise performance.

How does the SOT23 package affect thermal performance in continuous operation?

With R_thJS = 335 K/W, junction temperature rises 56 °C at P_tot = 175 mW. At 100 mW dissipation, ΔT = 33.5 °C-so ambient must stay ≤ 116.5 °C to hold T_J ≤ 150 °C. PCB copper area directly impacts actual R_thJA.

Does this part require external neutralization for stability?

Yes-S-parameter data shows |S₁₂| > −20 dB across 0.5–2 GHz, indicating potential instability. Neutralization via emitter degeneration or collector-base feedback is required for unconditional stability in broadband amplifier designs.