What is MD8002A Audio Amplifier and Its Working

An audio amplifier is one kind of electronic amplifier that is used to amplify electronic audio signals which have low power like the output signal from the radio receiver. These amplifiers are applicable in all kinds of sound systems like sound strengthening, home theater system, surround-sound system, audio systems in the home, entertainment center, and guitar amplifiers. In a typical audio playback chain, the audio amplifier is the last electronic stage before the signal is transmitted to the loudspeakers. The input of the audio amplifier is any audio source such as CD players, record players, cassette players, and digital audio players. Most of the amplifiers use low-level inputs. For instance, an audio amplifier’s input signal is the electric guitar signal. This signal measures a hundred microwatts and generates few watts which is used in small electronic devices like clock radios, a stereo system used in homes, etc. This article discusses an overview of the MD8002A Audio Amplifier.

What is MD8002A Audio Amplifier?

Definition: The MD8002A is one kind of audio power amplifier used to deliver 2.0 watts of power constantly to a BTL load with below 10% distortion from a power supply of 5V DC. It is specially designed to give high-quality o/p power using fewer amounts of components. It doesn’t use bootstrap or output coupling capacitors.

This amplifier is perfectly suitable for low voltage applications as well as audio speakers through a particular pop-click removing circuit. These amplifiers provide ideal pop-click characteristics in switch on & off conditions. This amplifier is unity-gain stable & arranged through external gain-setting resistors.

Pin Configuration

The pin configuration of the MD8002A Audio Amplifier includes 8 pins which are discussed below.

MD8002A Pin Diagram
MD8002A Pin Diagram
  • Pin1 (SD): This is a Shutdown Pin. Active high
  • Pin2 (BYP): This is a bypass capacitor pin
  • Pin3 (+IN): This is a +Ve i/p pin of the initial Amplifier
  • Pin4 (-IN): This is a -ve pin of the initial amplifier
  • Pin5 (VO1): This is a negative o/p
  • Pin6 (VDD): This is a +ve Supply Pin
  • Pin7 (GND): This is a ground pin
  • Pin8 (VO2): This is a +ve output pin


The main features of the MD8002A audio amplifier include the following.

  • It has the capability of an arrangement for an external gain
  • It is available in SOP8 Package
  • It is stable for unity gain
  • It doesn’t need any o/p coupling capacitors, bootstrap capacitors otherwise snubber networks.
  • Enhanced circuitry removes pop-click noise throughout turn ON & OFF conditions.


The main specifications of the MD8002A audio amplifier include the following.

  • The range of supply voltage is 2V to 6V
  • The o/p Power is 3W
  • The shutdown current is 0.6µA
  • The load impedance of audio is 3 Ohms
  • The improved PSSR is 60 dB at 217 Hz and 1kHz

Equivalent & Alternative IC’s

The equivalent and alternative ICs of this amplifier include the following.

  • An equivalent ICs of MD8002A audio amplifier is LM4871 and TDA2050
  • Alternatives ICs of MD8002A audio amplifier are AD620, LM386, JRC45558 & IC6283.

Where to Use?

This type of amplifier has a feature like a shut-down mode. The main intension of this IC is to offer output power with high-quality using fewer components. This amplifier doesn’t use capacitors like output coupling otherwise bootstrap. It is used in an audio speaker as well as low-voltage applications. This IC is the best choice for those who are looking for dual op-amp IC including wide bandwidth as well as high gain.

MD8002A Audio Amplifier Circuit

The circuit diagram of this audio amplifier is shown below. This circuit can be built with two operational amplifiers with different configurations. The gain of the primary op-amp is configurable externally whereas the second amplifier is fixed internally in inverting configuration with a unity gain.

MD8002A Audio Amplifier Circuit
MD8002A Audio Amplifier Circuit

The main components used in this circuit are Ri, Ci, Rf, Cf, and Cb which are discussed below.

  • An inverting input resistance (Ri) sets the gain of closed-loop within conjunction through feedback resistance (Rf). This resistor can form an HPF (high pass filter) using the input coupling capacitor (Ci) on fc = 1/(2πRi*Ci).
  • An input coupling capacitor (Ci) blocks the voltage of DC where the i/p of an amplifier ends. In addition, it creates an HPF using Ri on fc = 1/(2πRi*Ci).
  • The feedback resistance (Rf) fixes the gain of closed-loop within conjunction through Ri. So the gain of this is AVD=2*(Rf/Ri).
  • The supply bypass capacitor (Cs) gives the filtering of the power supply.
  • The bypass pin capacitor (Cb) gives a filtering of half-supply.

The primary op-amps closed-loop gain can be fixed by choosing the fraction of Rf & Ri whereas another amplifier gain can be set through the two internal resistors. In the circuit, we can observe that the first amplifier output is given as an input of the second amplifier which generates the signals which are equal in magnitude with 180° out of phase

Maximum Ratings

The maximum ratings of MD8002A audio amplifier include the following

  • The supply voltage ranges from-0.3V to 6V
  • Input voltage ranges from -0.3V to VDD+0.3V
  • Junction Temperature ranges from -40℃ to +150℃
  • Storage Temperature ranges from -65℃ to +150℃

Operating Ratings

The operating ratings of the MD8002A audio amplifier include the following.

  • The range of temperature is-40℃ ≦ TA ≦ 85℃
  • The supply voltage is 2.2V ≦ VDD ≦ 5.5V


The applications of audio amplifiers like MD8002A include the following.

  • Audio speakers
  • Audio Systems with Low Voltage
  • Audio Systems
  • Desktop Computers
  • Portable Computers

Thus, this is all about an overview of the audio power amplifier datasheet. This is one kind of audio power amplifier with mono bridged. It generates 3W of stable power for 3Ω BTL load. The main features are the protection of thermal shutdown, external gain set, unity-gain stability, etc. Here is a question for you, what is the supply voltage of this IC?