How To Design A Signal Amplification PC Board

Various kinds of circuit boards are essential for electronic devicesand the amplifier PCB is one of them. You need amplifiers to reproduce sounds, so the amplifier circuit board is vital for sound-generating devices, such as loudspeakers.

Understanding An Amplifier PCB

A PCB with an amplifier produces enhanced signals that input terminals require. Such a circuit board consists of electronic components to transfer signals. The components also increase the power of the amplifier by transferring signals through specific transistors. A substrate is an essential part of an amplifier circuit board like it’s a surface with components and it is composed of resin and fiberglass.

Though the amplifier is an independent component, it has several parts in it. An amplifier circuit board has many resistors and capacitors to perform various functions. Moreover, it has input and output terminals for both original and amplified signals.

Such a PCB can be small or large, depending on the device and its application. Generally, the headphones amplifiers are small, whereas the professional sound system has a large amplifier that singers and musicians often use. The size of a large amplifier Printed Circuit Board goes beyond 100 square inches.

The small amplifiers often depend on an external source for power supply whereas the battery-driven amplifiers are different.  Such PCBs are either power amplifiers or audio amplifiers.

How To Differentiate The Normal And Amplifier PCB

A normal PCB uses through-hole technology that helps drill holes and install PCB components. Surface mount technology is also another way of constructing a normal PCB.

On the other hand, the construction of an amplifier circuit board involves a schematic design. Certain design software helps place the components, whereasthe nature of the board determines its physical properties.

You need to consider the thermal and geometry factors while placing the components in an amplifier PCB. Likewise, in such a PCB, the power input and output work with respect to transistors’ resistance.

The amplifier circuit board has a better dielectric constant than a normal circuit board. But, the design of both kinds of PCBs needs a schematic diagram. You can also design a normal PCB manually like through Photomask.

What Are Heat Sinks In Amplifier PCB design?

There are heat sinks in the amplifier circuit boards which dissipate the heat caused during a PCB function. Engineers use aluminum to make heat sinks because it is highly conducive compared to other materials. Besides, aluminum resists corrosion and abrasion better than other metals.

The function of the heat sinks depends on two elements, including copper coins and thermovia.You need specific components to mount the heat sinks on the amplifier circuit board.Moreover, you also need solder pins and lock tabs during mounting. Heat sinks help a circuit board to manage its thermal propertywhich is the key element of the board.

Applications of Amplifier PCB

There are many applications of amplifier PCBs but their main function is to transform analog signals into digital ones.So, the amplification of the signals is the main thing in this case. Let’s see its applications one by one.

The amplifier PCB increases the amplitude signals, maintaining the frequency and several other elements.
This kind of PCB is able to transfer analog signals to square waves through the input saturation of a much high level.
The output resistance and voltage are also high in an amplifier PCB which helps it to produce enough output for the loudspeakers’ function.
It helps figure out the metal fatigue, ultrasonic cleaning, and ultrasound scanning.
The amplifier circuit board having a constant increase in the DC and AC is ideal for oscilloscope.
However, it has a low input resistance, and it works as a barrier between the circuitry and the receiver.Besides, it eliminates the signals it does not need.

Main Elements of An Amplifier Circuit Board

The board has certain characteristics as described below:

High Input Impedance: The high-input impedance is essential because it causes the voltage drop only on an amplifier, which is not possible in the low-input impedance. So, the amplifier PCBs need materials with a low-input impedance. You can eliminate the loading through a high-input impedance. The amplifier absorbs more current if its input impedance is low.

Enough Bandwidth: The bandwidth should be well-balanced in an amplifier circuit board to get compatible with the frequency being amplified. There will be no signal frequency if the bandwidth is narrow. Likewise, the wider bandwidth causes a lot of noise, so the bandwidth has to be undercontrol.

Increased Open Loop Signals: The amplifier increases signals’ power that you can evaluate between the input and output channels when the circuit board gets no feedback. The board might get feedback when the open-loop gains are high.

Stability of An Amplifier

You have to consider the amplifier’s stability while designing it. Signal distortions often happen when the amplifier is not stable. Many instabilities happen in the function of an amplifier PCB which can be controlled by considering certain factors while making its layout. By considering these factors, you can eliminate the board- spin failure, power strength, and signal integrity issues during its function.

The amplifier gets unstable if there are changes in the input signals. Some common issues with the amplifier stability are as below.

Ringing issues

In this case, the output can create a damped oscillation, reaching a stable output. It might involve undershooting and overshooting the output.

Oscillation Issues

It happens because of the load input and the impedance of the amplifier output. Such an issue affects the transfer ability of the amplifier by creating a pole.

Various Parasitic Feedbacks

It involves parasitic coupling which causes negative or positive feedback to the input terminal. This is a very unstable behavior of an amplifier that you can identify through an on-amp circuit.

Why Is Amplifier Stability Important?

When it comes to the RF systems, the amplifier stability becomes evident, like in telecom systems that involve the RF frequencies. Such systems useRF power amplifiers having high-signal power and frequencies, so you have to be careful while placing them in the signal chain.

When the layout has errors due to unnecessary parasitics, the output signals would become unstable. So, you must test the RF power to check the unstable behavior of the amplifier circuit board. Such management ensures that the RF system will function correctly.

Types of Amplifier PCBs

The amplifier PCBs have different categories, depending on their nature. In general, the number of power and audio amplifier circuit board designs is above 108. Engineers also classify them as A, B,C, and going up to G.

Group AAmplifier

You will see the gain and high linearity in this amplifier PCB layout. Besides, it has a 360-degree conduction angle. It remains functional during the entire signal’s input. Moreover, it includes an always-ON transistor.

Group B Amplifier

It involves two active devices and users can bias the amplifiers step-wise during the positive and negative cycles of the signals.

Group AB Amplifier

You can have the AB amplifier to eliminate the cross-over distortion of the signals.

Group C Amplifier

It is also known as a tuned amplifier that works through two modes, such as turned and unturned mode. Such a layout’s conduction angle is lower than 180 degrees and it is 60 to 70 percent effective.

Group D Amplifier

Such a layout involves the Pulse Width that changes its input signals.However, there is no role of conduction angle in this case. Besides, it does not need a linear gain.

Group E Amplifier

It is the most effective power amplifier that involves switching topology and radio frequencies as well.

Group F Amplifier

Such an amplifier comes up with high impedance like in harmonics. It includes the square and sine waves.

Group G Amplifier

It enhances a circuit board’s function using less power. Such amplifiers depend on the systems known as rail switching.

FAQs

What Is An Amplifier Circuit Board?

The construction of an amplifier circuit board involves a schematic design. You need to consider the thermal and geometry factors while placing the components in an amplifier PCB. Besides, the power input and output work with respect to transistors’ resistance.

What Is A Normal PCB?

A normal PCB uses through-hole technology that helps drill holes and install PCB components. Whereas surface mount technology is also another way of constructing a normal PCB.

What Are Heat Sinks In An Amplifier PCB?

Heat sinks in an amplifier PCB dissipate the heat caused during a PCB function. The function of the heat sinks depends on two elements, including copper coins and thermovia. You need specific components to mount the heat sinks on the amplifier circuit board.

Conclusion

The amplifier PCB has many uses as discussed above. You have to consider several factors while designing it. You can get the desired layout by controlling certain issues while creating the layout of an amplifier circuit board. You should also plan the type of amplifier PCB your device requires.

Would like to know more about designing a signal amplifier or PC Board assembly? Email us at sales@pnconline.com

Written by Sam Sangani

Sam Sangani is the President & CEO of PNC Inc., a Nutley, NJ based Printed Circuit Board manufacturer. Sam graduated from L. D. Engineering College with a BS Degree in Mechanical Engineering. He also continued his education and graduated from Steven’s Institute of Technology where he acquired a Master’s degree in Computer Science.

After completion of his BS, Sam worked as a QC Manager, for Xerox, Romania and London. He was responsible for the Quality Control of Cable and Wire Harness imports from Romania. After completing his Master’s Degree, he worked as a Senior Programmer with IBM, Tucson, Arizona. Sam was responsible for leading the Mainframe System Programming Team.

In 1997, Sam acquired PNC INC., a Nutley, NJ based PC Board fabrication Shop. From 1997-2013, Sam has made tremendous improvements and changes within PNC INC., as he added many new Products and Technologies in PNC’s portfolio. With his proven track record and leadership, PNC has never had an unprofitable year and has continued its growth yearly since 1997.

His current responsibilities are Strategic Planning, Corporate Management, New Business Ventures, Sales & Marketing, Trade Shows, Professional Services and leading productive teams to achieve peak potential. He has also utilized Lean Management techniques which have built a foundation for PNC’s high-paced growth. Sam also enjoys real-estate investing, web design & SEO, trading stocks, options, futures and Forex markets.