TBA820M Monolithic Integrated Audio Amplifier

Overview

The TBA820M is a monolithic integrated circuit designed for use as a low-power audio amplifier. Housed in an 8-lead dual in-line plastic package (DIP), this component is optimized for portable and battery-operated applications where space and power efficiency are critical. The TBA820M offers a balance of performance and simplicity, making it suitable for a variety of audio amplification needs.

With its low quiescent current and wide operating voltage range, the TBA820M is particularly well-suited for consumer electronics, educational projects, and small audio systems. The amplifier can drive small speakers directly, providing adequate sound output for personal listening or small room applications.

Features

• Low quiescent current consumption, ideal for battery-powered devices
• Wide operating voltage range: 3V to 16V
• Output power up to 1.2W (typical at 12V, 8Ω load)
• Minimum external components required for operation
• Good ripple rejection ratio
• Internal thermal overload protection
• Low harmonic distortion
• No cross-over distortion
• Designed for portable and space-constrained applications

Applications

The TBA820M finds use in various audio applications where compact size and low power consumption are prioritized. Typical applications include:

• Portable radios and cassette players
• Intercom systems
• Educational electronics kits
• Small public address systems
• Battery-powered audio devices
• Computer sound systems
• Electronic toys with sound output
• DIY audio projects

The amplifier's versatility makes it particularly valuable in designs where space is limited and power efficiency is crucial.

Electrical Characteristics

The following table summarizes the key electrical characteristics of the TBA820M under typical operating conditions (unless otherwise specified):

Absolute Maximum Ratings

• Supply Voltage (V_CC): 16V
• Output Peak Current: 1.5A
• Power Dissipation: 1W (at T_amb ≤ 45°C)
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -55°C to +150°C

Operating Characteristics (V_CC = 9V, T_amb = 25°C)

• Quiescent Current: 4mA (typical)
• Voltage Gain: 39dB (typical)
• Bandwidth (-3dB): 20Hz to 20kHz
• Total Harmonic Distortion: 0.3% (typical at 500mW, 1kHz)
• Input Resistance: 5MΩ (typical)
• Output Power:
  • 500mW (typical at 9V, 8Ω load)
  • 1.2W (typical at 12V, 8Ω load)
• Ripple Rejection: 40dB (typical)

Package Information

The TBA820M is available in a standard 8-pin DIP (Dual In-line Package) with the following mechanical specifications:

• Package Type: DIP-8
• Package Material: Plastic
• Lead Material: Solder-coated copper alloy
• Pin Spacing: 2.54mm (0.1 inch) between pins
• Row Spacing: 7.62mm (0.3 inch) between rows
• Package Dimensions:
  • Length: 9.81mm (max)
  • Width: 6.35mm (max)
  • Height: 4.57mm (max)
• Weight: Approximately 0.5 grams

Pin Configuration

The pinout configuration for the TBA820M is as follows:

• Pin 1: Compensation
• Pin 2: Input
• Pin 3: Feedback
• Pin 4: Ground
• Pin 5: Output
• Pin 6: V_CC (Supply Voltage)
• Pin 7: Bootstrap
• Pin 8: Compensation

Design Considerations

When implementing the TBA820M in a circuit design, several factors should be considered to ensure optimal performance:

Power Supply

The amplifier can operate from a wide range of supply voltages (3V to 16V). For battery-powered applications, a supply voltage between 6V and 9V typically provides a good balance between output power and battery life. Higher voltages will increase output power but also increase current consumption.

Thermal Management

While the TBA820M includes thermal overload protection, proper heat dissipation should still be considered, especially when operating near maximum ratings. Ensure adequate ventilation and consider the thermal characteristics of the PCB layout.

Input Configuration

The input impedance is relatively high (5MΩ typical), allowing direct connection to most audio sources. However, for best performance with low-impedance sources, an input coupling capacitor should be used.

Output Configuration

The output is designed to drive small speakers directly. For optimal performance, match the speaker impedance to the expected output power requirements. A series output capacitor may be required to block DC current in some configurations.

Typical Application Circuit

A basic application circuit for the TBA820M includes the following components:

• Power supply decoupling capacitor (100µF recommended)
• Input coupling capacitor (0.1µF to 1µF typical)
• Feedback network resistors
• Bootstrap capacitor (100µF typical)
• Output coupling capacitor (220µF to 470µF for 8Ω speaker)

The exact component values may vary depending on specific application requirements and desired performance characteristics.

Conclusion

The TBA820M provides a cost-effective, space-efficient solution for low-power audio amplification needs. Its combination of low quiescent current, reasonable output power, and simple implementation makes it particularly suitable for battery-operated devices and space-constrained applications. While not intended for high-fidelity applications, it offers more than adequate performance for many consumer and educational applications where simplicity and efficiency are prioritized over ultimate audio quality.

Designers should carefully consider the electrical characteristics and package information when incorporating the TBA820M into their projects to ensure reliable operation and optimal performance across the intended operating conditions.