Advantages and Disadvantages of Using Composite Amplifiers
The world of electronic PCB design is witnessing a significant shift, with composite amplifiers playing a pivotal role, particularly in power amplifiers. This transformation is driven by several key trends and technologies that are reshaping the landscape of power amplifiers, especially in high-frequency applications such as 5G and motor drives.
One of the most notable advancements is the use of Wide Bandgap Semiconductors, specifically gallium nitride (GaN) technology on silicon carbide (SiC) substrates. These modern power amplifiers offer higher power density, greater efficiency, and improved thermal performance compared to traditional silicon devices. For instance, Qorvo’s TGA2578-CP utilizes a 0.25 µm GaN on SiC process to deliver 30 W saturated output power with over 30% power-added efficiency and over 26 dB gain across a 2 to 6 GHz frequency range.
High-performance power amplifiers generate significant heat. To effectively dissipate this heat, recent designs integrate superior thermal solutions such as copper bases in packaging and thermal vias in PCBs. This approach supports higher power operation and enhances device reliability.
Compact and efficient circuit designs are another critical aspect of modern composite amplifiers. Reference designs like EPC’s EPC9196 leverage thermally enhanced eGaN FETs to produce highly compact inverter and power amplifier solutions. These designs support medium-voltage motor drives with minimal switching losses, low dead time, and smooth performance at high switching frequencies.
Advanced PCB materials and multilayer structures are also essential for modern composite amplifiers. The use of low-loss dielectric materials and multilayer PCBs reduces signal loss at high frequencies and supports the complex circuitry required for modern composite amplifiers in telecommunications.
Modern composite amplifiers often feature integrated DC blocking capacitors, matching networks tuned to 50 Ω, and RoHS-compliant packaging. These integrations simplify system design and boost amplifier stability.
Composite amplifiers offer several benefits over traditional amplifiers. They exhibit higher gain, boosted slew rates, and lower distortion. The composite structure enhances the load driving capability of the electronic circuitry, removing errors caused by thermal feedback loops and self-heating. Composite amplifiers also offer superior DC performance levels, retaining the DC characteristics of the first input amplifier, and better DC output-offset, which is not affected by the excess load placed on output transistors.
Power amplifiers using composite amplifiers are gaining traction in microwave and RF applications due to their highly stabilized gain and better offset output voltage. The negative feedback loop in composite amplifiers can increase output resistance, particularly in cases related to current shunt and current series feedback amplifiers.
In summary, the key features of recent composite power amplifiers in PCB design include GaN-based high-efficiency devices, advanced thermal management strategies, compact and highly integrated circuit modules, utilization of innovative PCB materials and multilayer approaches, and incorporation of electrical and environmental compliance features. These advancements enable power amplifiers to meet the increasingly demanding performance, efficiency, and reliability needs of current electronic systems. Wider applications of composite amplifiers are expected over the coming years, with the composite structure limiting the use of zero adjustment pot, thereby reducing excess component cost.
Technology is driving a significant shift in the world of electronic PCB design, particularly in power amplifiers, as composite amplifiers equipped with Wide Bandgap Semiconductors like gallium nitride (GaN) technology on silicon carbide (SiC) substrates offer higher power density, greater efficiency, and improved thermal performance compared to traditional silicon devices. (1)
Advanced PCB materials and multilayer structures are essential for modern composite amplifiers, as the use of low-loss dielectric materials and multilayer PCBs reduces signal loss at high frequencies and supports the complex circuitry required for modern composite amplifiers in telecommunications. (2)
