The LM4850MT is a Boomer series audio power amplifier designed for demanding applications in portable devices. Manufactured by National Semiconductor (now Texas Instruments), it is capable of delivering significant output power into low impedance loads. This amplifier is known for its low distortion, low noise, and built-in shutdown function, making it ideal for battery-powered equipment.

Applications

• Cellular phones
• PDAs
• Portable media players (MP3 players, etc.)
• Laptop computers
• Portable gaming devices

Features

• Output Power: Typically 1W into 8Ω with a 5V supply
• Low Total Harmonic Distortion + Noise (THD+N)
• Integrated shutdown function
• Click and pop suppression circuitry
• Small Surface Mount Technology (SMT) package
• Available in thermally enhanced packages

Benefits

• High-quality audio: Low THD+N ensures clear and accurate audio reproduction.
• Extended battery life: The shutdown function minimizes power consumption when the device is not in use.
• Reduced audible artifacts: Click and pop suppression eliminates unwanted noise during power-up and power-down.
• Space-saving design: The small SMT package allows for compact designs in portable devices.
• Thermal performance: Thermally enhanced packages improve heat dissipation, allowing for higher output power.

Additional Details

The LM4850MT typically operates from a single 2.0V to 5.5V power supply. It features a gain that can be adjusted using external resistors. The amplifier is designed to drive low impedance loads, typically 8Ω or 4Ω speakers. The shutdown function can be controlled by a logic signal, allowing the system to disable the amplifier when it is not needed, further reducing power consumption. Detailed application notes and design examples are available from Texas Instruments to assist designers in implementing the LM4850MT in their products.

Proper layout and decoupling are critical for achieving optimal performance with the LM4850MT. It's recommended to follow the manufacturer's guidelines for PCB layout to minimize noise and distortion. Additionally, using appropriate decoupling capacitors near the power supply pins is essential for stable operation.