Lm3485 Led Demo Board

The LM4550 is an audio codec designed for PC systems, fully compliant with PC99 standards, and performs the analog-intensive functions of the AC97 Rev2.1 architecture. It utilizes 18-bit Sigma-Delta analog-to-digital (A/D) and digital-to-analog (D/A) converters, providing a dynamic range of 90 dB. The LM4550 is tailored to ensure a high-quality audio path and encompasses all necessary analog functionalities for a PC audio system. It includes full duplex stereo A/Ds and D/As, along with an analog mixer featuring four stereo inputs and three mono inputs, each equipped with individual gain, attenuation, and mute controls. Additionally, the LM4550 incorporates a stereo headphone amplifier with independent gain control and supports National Semiconductor's 3D Sound stereo enhancement and variable sample rate conversion. The sample rates for both A/D and D/A can be programmed separately with a resolution of 1 Hz, accommodating any rate between 4 kHz and 48 kHz. The LM4550 also supports the connection of multiple codecs in a system to deliver up to six channels for surround sound applications. These multi-codec systems can be constructed using the standard AC-Link format, which allows for one serial data stream per codec, or by utilizing a unique feature from National Semiconductor that enables chaining codecs together, requiring only a single data stream to the controller. The AC97 architecture effectively separates the analog and digital functions of the PC audio system, facilitating both design flexibility and enhanced performance.

The LM4550 audio codec is a sophisticated component that integrates seamlessly into PC audio systems, ensuring high fidelity and versatility in audio processing. It features advanced 18-bit Sigma-Delta A/D and D/A converters, which are crucial for achieving superior audio quality with a dynamic range of 90 dB. This level of performance is essential for applications requiring precise audio reproduction, such as music production, gaming, and multimedia playback.

The codec's full duplex capability allows simultaneous audio input and output, which is particularly beneficial for applications such as voice communication and live audio streaming. The integrated analog mixer with multiple inputs provides flexibility in audio source management, enabling users to mix different audio signals effectively. Each input's independent controls for gain, attenuation, and mute ensure precise audio adjustments, catering to various audio scenarios.

The inclusion of a stereo headphone amplifier with independent gain control enhances the user experience by allowing tailored audio output levels for different headphones or speakers. The support for 3D Sound stereo enhancement further enriches the auditory experience, providing a more immersive sound environment.

One of the standout features of the LM4550 is its programmable sample rate conversion capabilities. This flexibility allows the codec to adapt to various audio formats and requirements, making it suitable for a wide range of applications. The ability to set sample rates between 4 kHz and 48 kHz with 1 Hz resolution ensures compatibility with various audio standards.

Moreover, the codec's ability to connect multiple devices using the AC-Link format or through a unique chaining feature enables the construction of complex audio systems capable of delivering surround sound. This is particularly advantageous for home theater systems and advanced gaming setups, where multi-channel audio is essential for an engaging experience.

Overall, the LM4550 stands as a robust solution for high-quality audio processing in PC systems, combining flexibility, performance, and advanced features to meet the demands of modern audio applications.The LM4550 is an Audio CODEC for PC systems which is fully PC99 compliant and performs the Analog intensive functions of the AC97 Rev2. 1 architecture. Using 18-bit Sigma-Delta A/Ds and D/As, the LM4550 provides 90 dB of Dynamic Range. The LM4550 was designed specifically to provide a high quality Audio path and provide all Analog functionality in

a PC Audio system. It features full duplex stereo A/Ds and D/As and an Analog mixer with 4 stereo and 3 mono inputs, each of which has separate gain, attenuation and mute control. The LM4550 provides a stereo Headphone Amplifier with an independent gain control and also supports Nationals 3D Sound stereo enhancement and variable sample rate con- version.

The sample rate for the A/D and D/A CAN be pro- grammed separately with a resolution of 1 Hz to convert any rate between 4 kHz48 kHz. The LM4550 features the ability to connect several codecs together in a system to provide up to six channels for sur- round sound applications.

Multiple codec systems CAN be built using the standard AC-Link format of one serial data stream per codec, or using a unique National Semiconductor feature for chaining codecs together. This chain feature re- quires only a single data stream to the controller. The AC97 architecture separates the Analog and digital func- tions of the PC Audio system allowing both for system design flexibility and increased performance.

By National Semiconductor Corporation 🔗 External reference