TDA2822 Dual Power Amplifier: Pin Configuration, Applications and Additional Information

Ⅰ. Overview of TDA2822 amplifier

Ⅱ. TDA2822 symbol, footprint and pin configuration

Ⅲ. Technical parameters of TDA2822 amplifier

Ⅳ. Features of TDA2822 amplifier

Ⅴ. How does the TDA2822 amplifier work?

Ⅵ. What are the applications of TDA2822 amplifier?

Ⅶ. TDA2822 amplifier usage failure

TDA2822 is a dual-channel monolithic power amplifier integrated circuit manufactured by ST Microelectronics. It is widely used in audio amplifiers in multimedia, pocket, cassette players and active speakers. It features low crossover distortion, low quiescent current, and is available in an 8-pin plastic dual-in-line package. The chip can operate stably within a wide power supply voltage range of 3V to 15V, and shows the advantages of simple circuit, excellent sound quality, and wide voltage range.

Replacements and equivalents:

• C4556C

• TEA2025B

• TDA7268

• TEA2025D

• NJM4560

• It is an audio chip suitable for mono bridged or stereo lines. In the mono bridge working state, it can provide high-power, high-quality audio output; while in the stereo line working state, it can provide balanced stereo sound quality.

• It comes in dual in-line 8-pin plastic package.

• It has a lower distortion rate, resulting in clearer sound quality.

• Its wide supply voltage range, from 3V to 15V, makes it particularly suitable for operation at low supply voltages.

• It has two independent audio channels. These two channels can amplify the left and right channels respectively, making the audio signal output clearer and with a stronger three-dimensional effect.

1. Working principle

Its working principle mainly involves input circuit, differential amplifier circuit, and output circuit.

(1) Input circuit

The input circuit of TDA2822 adopts DC coupling method. The audio signal first enters the input end of the integrated circuit through the coupling capacitors C1 and C2. These two capacitors play a role in blocking DC coupling and isolating the DC component in the input signal. At the same time, the input end is also connected with a bias resistor to adjust the DC bias voltage of the input signal to an appropriate range to ensure the normal operation of the differential amplifier circuit.

(2) Differential amplifier circuit

TDA2822 uses a dual differential amplifier structure. In this part, the input audio signal will go through two stages of amplification. It first passes through differential amplifiers Q1 and Q2, which are transistors operating in common emitter mode. The bases of Q1 and Q2 are connected to the output terminal and the negative feedback loop at the same time, and the amplification power is controlled through precise negative feedback to ensure the amplification effect of the audio signal. Next, it passes through the cascaded common-emitter amplifiers Q3 and Q4, which further amplify the audio signal. The combination of these two amplifier stages allows the TDA2822 to achieve a larger amplification factor of the audio signal.

(3) Output circuit

The TDA2822's output circuit features a collector connection. Within this output circuit, an output terminal links to a load resistor RL, facilitating the conversion of current into a voltage via RL to achieve audio signal output. Additionally, to enhance output current stability and amplification, TDA2822 incorporates a biasing current source. These RL load resistors serve a dual purpose: not only connecting to speakers or other audio equipment but also transforming current into audio signals.

2. Typical working principle diagram

This hearing aid is composed of the TDA2822 bi-amplified integrated circuit and a small number of peripheral components. Compared with common models on the market, it boasts substantial output power and an extensive voltage range. Operating within the voltage range of 1.8 to 15V, it is well-suited for individuals with mild to moderate hearing impairment.

The working principle of this hearing aid is relatively simple. First, the electret microphone is connected to a high-gain drain output circuit to convert external sound waves into electrical signals. Then, the BTL power amplifier circuit composed of TDA2822 amplifies the audio signal output by the microphone and generates enough power to drive the headset to produce sound. In order to reduce the loss caused by coupling, we use transformer coupling and connect C2 to the primary to filter out part of the induced noise. On the secondary level, it is connected to the RP to control the volume. Additionally, a decoupling circuit, formed by R1 and C1, is in place to prevent power supply signals from inducing feedback. R2 and C6 are utilized to offer frequency compensation for the BTL circuit.

• Car audio system

• Preamplifier

• Power amplifier

• Communication equipment: wireless headsets and Bluetooth speakers

• Portable music player

1. Heating

The issue arises from either excessive power usage or inadequate heat dissipation in the power amplifier circuit. To address this concern, we can implement solutions like lowering power consumption, enhancing circuit design, and optimizing heat dissipation.

2. Output buzzing sound

This may be caused by unreasonable circuit design, missing anti-oscillation circuit, improper selection of load resistor and supply voltage, missing or failed DC blocking capacitor, etc. We can optimize the circuit design, add RC anti-oscillation circuits, select appropriate load resistors and supply voltages, add DC blocking capacitors, etc.

3. Crossover distortion

The issue arises from the incorrect configuration of the transistor or integrated circuit's operating point within the power amplifier circuit. We can modify the input signal amplitude or bias voltage to fine-tune the power amplifier circuit's operating point.

Frequently Asked Questions

1. How many channels does the TDA2822 have?

The TDA2822 is a dual-channel amplifier, meaning it has two independent amplification channels, typically labeled as left and right channels.

2. What is the function of TDA2822?

TDA2822 is one kind of Op-amp (operational amplifier) that can be used in low output applications like a stereo amplifier. This IC has some features like it is available in 16-pin power DIP package, low crossover distortion, low-quiescent current. The IC TDA2822 can be worked with a supply voltage of 3V to 15V.

3. What are the typical applications for the TDA2822?

Typical applications for the TDA2822 include portable radios, small audio amplifiers, intercom systems, and other low-power audio amplification needs.

4. What is the replacement and equivalent of TDA2822?

You can replace the TDA2822 with the C4556C, TEA2025B, TDA7268, TEA2025D or NJM4560.

5. What is the difference between TDA2822 and TDA2822M?

The package of TDA2822 is the same as TDA2822M. The difference is that: TDA2822M can work from 3V to 15V, while the highest working voltage of TDA2822 is only 8V. The higher the voltage, the higher the output power, so the output power of TDA2822M can be higher (dual-channel).