IN Brief:
- The PMA5-223+ covers 10MHz to 22GHz using a distributed GaAs pHEMT amplifier architecture.
- Typical specifications include +33dBm saturated output power, 15.5dB gain, and +43dBm OIP3 at 10GHz.
- A 5 × 5mm surface-mount package and bare-die option support different integration requirements.
Mini-Circuits has introduced the PMA5-223+, a broadband GaAs pHEMT power amplifier operating from 10MHz to 22GHz. The monolithic microwave integrated circuit provides typical saturated output power of +33dBm, equivalent to approximately 2W, alongside 15.5dB typical gain. Its 5 × 5mm package and integrated 50Ω matching are intended for RF systems requiring substantial frequency coverage within a compact assembly.
The new device uses a distributed amplifier architecture, allowing amplification across a wider frequency range than would normally be practical with a conventional narrowband matching network. Mini-Circuits describes it as the widest-bandwidth MMIC power amplifier in its portfolio, with applications extending from general-purpose test instrumentation to satellite communications, radar, and electronic warfare equipment.
A distributed amplifier combines the operation of several transistor sections through transmission-line structures. The input signal reaches the active devices along a common path, while their amplified contributions are combined at the output. Controlling the propagation characteristics and impedance relationships across those structures allows the circuit to maintain useful amplification over a broad frequency range.
A single RF signal chain covering widely separated bands requires gain and impedance behaviour that remain usable as operating frequency changes. A narrowband amplifier may provide more tightly optimised performance over a restricted range but lose gain outside it. The distributed arrangement broadens the supported spectrum, with the designer balancing bandwidth against efficiency, noise, linearity, and available output power.
Mini-Circuits has implemented the PMA5-223+ using gallium arsenide pseudomorphic high-electron-mobility transistor technology. GaAs pHEMT devices are used in microwave circuitry because their electrical characteristics support high-frequency operation. The transistor process and distributed architecture work together to provide the specified bandwidth, while the final response remains dependent on the operating frequency and electrical conditions.
The amplifier’s typical linear gain is 15.5dB. Gain describes the increase in signal power between the input and output while the device operates within its linear region. A broadband design must maintain an acceptable response across its intended frequency range, but the nominal gain specification does not mean that every frequency receives exactly the same amplification.
Output power has a separate relationship with signal fidelity. Mini-Circuits specifies +33dBm typical saturated power, corresponding to approximately 2W, when the amplifier approaches its output limit. At saturation, increasing the input signal no longer produces a proportional increase in output power, and distortion can become significant. Applications requiring low distortion may therefore need to operate below the device’s saturated output rating.
The manufacturer’s catalogue lists a typical 1dB compression output power of 31.5dBm. This identifies an operating condition where gain has fallen by 1dB from its small-signal value. It provides a more relevant reference than saturated power when evaluating the onset of compression, although the required operating margin depends on the waveform and acceptable distortion of the intended application.
Linearity is also characterised by the output third-order intercept point, or OIP3. Mini-Circuits reports +43dBm at 10GHz using a two-tone measurement with +20dBm output power per tone. Third-order intermodulation products can create unwanted signals close to the frequencies of the original inputs, making their suppression important where several RF carriers occupy neighbouring parts of the spectrum.
The specified OIP3 result belongs to the stated measurement conditions. Intermodulation performance can vary with frequency, output level, and device bias, so it should not be interpreted as a fixed value throughout the complete 10MHz to 22GHz range. The required linearity margin must be established using the signals and operating conditions of the equipment incorporating the amplifier.
Integrated 50Ω input and output matching simplifies connection to the RF interfaces commonly used in test equipment and microwave assemblies. It reduces the need for an external broadband matching network, although transmission-line geometry, grounding, and the transition between the printed circuit board and package remain important. At the upper end of the operating range, small layout discontinuities can influence impedance matching and signal loss.
The surface-mount version uses a 32-lead QFN-style package measuring 5 × 5mm. That footprint allows the amplifier to be incorporated into relatively dense RF boards, provided the surrounding layout supplies adequate connections and thermal management. Power dissipation depends on bias conditions, output level, and device efficiency, making heat removal through the package and circuit board part of the final design.
A bare-die version provides an alternative where the semiconductor must be integrated into a specialised microwave assembly. Die-level installation changes the mechanical and electrical arrangement, requiring suitable attachment, interconnection, and protection. Such implementations can be appropriate where equipment manufacturers need tighter control over the geometry of the RF signal path or the package surrounding the device.
Broadband measurement systems could use the amplifier to provide gain across multiple test frequencies without changing hardware for each band. Satellite communications and radar applications impose different operating requirements, particularly for linearity, available output power, and environmental conditions. The device’s wide frequency coverage gives designers a common component option, while its operating point must still be selected for the particular signal.
The PMA5-223+ is listed in Mini-Circuits’ current amplifier portfolio in packaged and bare-die forms. Its principal engineering characteristics are the combination of 10MHz to 22GHz coverage, typical 2W saturated power, and integrated matching. Evaluation in a finished RF circuit will determine the gain flatness, distortion, thermal performance, and output margin available under the required operating conditions.
