LM4991LD/NOPB

Product Overview

• Category: Integrated Circuit (IC)
• Use: Audio Amplifier
• Characteristics: Low Noise, High Performance
• Package: 8-Pin SOIC (Small Outline Integrated Circuit)
• Essence: Class AB Audio Power Amplifier
• Packaging/Quantity: Tape and Reel, 2500 units per reel

Specifications

• Supply Voltage: 2.5V to 5.5V
• Output Power: 1.1W into 8Ω at 5V
• Total Harmonic Distortion + Noise: 0.1% (typical) at 1kHz, 1W
• Quiescent Current: 4mA (typical)
• Shutdown Current: 0.01μA (typical)
• Operating Temperature Range: -40°C to +85°C

Pin Configuration

The LM4991LD/NOPB IC has the following pin configuration:

___________ | | NC |1 8| VCC IN- |2 7| SHUTDOWN IN+ |3 6| OUT GND |4 5| BYPASS |___________|

Functional Features

• Low noise audio amplifier suitable for portable devices
• Class AB operation for efficient power utilization
• Shutdown mode for power-saving when not in use
• Bypass pin for improved low-frequency response
• Single-ended input with differential output

Advantages and Disadvantages

Advantages: - Low noise performance enhances audio quality - Efficient power utilization due to Class AB operation - Shutdown mode reduces power consumption during idle periods - Small package size allows for space-constrained designs

Disadvantages: - Limited output power of 1.1W may not be sufficient for high-power applications - Single-ended input limits compatibility with balanced audio systems

Working Principles

The LM4991LD/NOPB is a class AB audio power amplifier that amplifies low-level audio signals to drive speakers or headphones. It operates on a supply voltage range of 2.5V to 5.5V, making it suitable for portable devices.

The IC features a differential input stage that provides high common-mode rejection and low distortion. The amplified audio signal is then delivered through the output pin, which can directly drive an 8Ω speaker.

To conserve power, the LM4991LD/NOPB includes a shutdown mode that reduces the quiescent current to a minimum when the amplifier is not in use. Additionally, the bypass pin allows for improved low-frequency response by bypassing the internal feedback network.

Detailed Application Field Plans

The LM4991LD/NOPB is commonly used in various portable audio applications, including:

1. Mobile phones and smartphones
2. Portable media players
3. Tablets and laptops
4. Bluetooth speakers
5. Gaming consoles
6. Personal digital assistants (PDAs)

Due to its low noise characteristics and compact package, the LM4991LD/NOPB is well-suited for these applications where space and audio quality are crucial.

Detailed and Complete Alternative Models

1. TPA3110D2: Class D audio amplifier with higher output power and efficiency.
2. LM386: Low voltage audio power amplifier with adjustable gain.
3. MAX9744: Stereo class D audio amplifier with integrated volume control.
4. TDA7265: Dual bridge audio amplifier with wide supply voltage range.

These alternative models offer different features and specifications, providing options for various audio amplifier requirements.

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