Si4734/35-B20

4.7. Digital Audio Interface (Si4735 Only)

The digital audio interface operates in slave mode and supports three different audio data formats:

„I2S

„Left-Justified

„DSP Mode

4.7.1. Audio Data Formats

In I2S mode, by default the MSB is captured on the second rising edge of DCLK following each DFS transition. The remaining bits of the word are sent in order, down to the LSB. The left channel is transferred first when the DFS is low, and the right channel is transferred when the DFS is high.

In Left-Justified mode, by default the MSB is captured on the first rising edge of DCLK following each DFS transition. The remaining bits of the word are sent in order, down to the LSB. The left channel is transferred first when the DFS is high, and the right channel is transferred when the DFS is low.

In DSP mode, the DFS becomes a pulse with a width of 1 DCLK period. The left channel is transferred first, followed right away by the right channel. When transferring the digital audio data in DSP mode, the MSB of the left channel can be transferred on the first rising edge of DCLK following the DFS pulse or on the second rising edge.

In all audio formats, depending on the word size, DCLK frequency, and sample rates, there may be unused DCLK cycles after the LSB of each word and before the next DFS transition and MSB of the next word. In addition, if preferred, the user can configure the MSB to be captured on the falling edge of DCLK via properties.

The number of audio bits can be configured for 8, 16, 20, or 24 bits.

4.7.2. Audio Sample Rates

The device supports a number of industry-standard sampling rates including 32, 40, 44.1, and 48 kHz. The digital audio interface enables low-power operation by eliminating the need for redundant DACs on the audio baseband processor.

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Silicon Laboratories SI4734/35-B20 manual Digital Audio Interface Si4735 Only, Audio Data Formats, Audio Sample Rates
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SI4734/35-B20 specifications

Silicon Laboratories SI4734/35-B20 is an advanced, highly integrated broadcast radio receiver designed for various consumer applications. Hailed for its compactness and versatility, the SI4734/35-B20 offers extensive features that enable radio reception across multiple frequency bands, including AM, FM, and shortwave. It caters to the needs of manufacturers looking to incorporate reliable radio capabilities into their devices, ensuring quality sound and performance without the cumbersome designs typically associated with traditional radio receivers.

At the heart of the SI4734/35-B20 are performance-optimized technologies. One standout feature is the device's ability to support digital and analog processing simultaneously, utilizing Silicon Labs’ proprietary digital signal processing (DSP) technology. This architecture not only enhances signal clarity but also helps in mitigating noise, enabling users to experience a superior audio quality across varied environments.

Another notable characteristic of the SI4734/35-B20 is its low power consumption, making it ideal for battery-operated devices. The receiver employs sophisticated power management techniques that allow it to operate efficiently, prolonging battery life while maintaining optimal performance. In this context, the “sleep” mode and fast wake-up times contribute to significant energy savings, affirming its suitability for portable applications.

The SI4734/35-B20 is designed with a robust set of features for ease of integration into various systems. The device supports multiple programmable interfaces, including I2C, providing flexibility in communication with microcontrollers and facilitating straightforward integration into existing designs. Because of its programmable architecture, developers can customize the receiver’s capabilities according to the specific needs of their applications.

Additional features include automatic frequency control (AFC) for stability in tuning, allowing seamless transitions while listening to programs. The built-in AGC (automatic gain control) optimizes the receiver's sensitivity to ensure clear reception even in weak signal conditions.

The SI4734/35-B20 also possesses a wide frequency range, accommodating both standard and niche applications. Its compact form factor and surface-mount technology (SMT) footprint further enhance its appeal to developers seeking to maximize board space in their designs.

In conclusion, the Silicon Laboratories SI4734/35-B20 is a significant advancement in radio receiver technology, combining advanced DSP, low power consumption, and ease of integration. These attributes make it a preferred choice for engineers and manufacturers looking to deliver high-quality audio experiences across a range of consumer electronics, from radios to multifunctional smart devices.
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