UDA1335H

General description

The UDA1335H is a stereo CMOS codec incorporating bitstream converters designed for implementation in USB-compliant audio peripherals and multimedia audio applications. The UDA1335H is an adaptive asynchronous sink USB audio device with a continuous sampling frequency range from 5 to 55 kHz. It contains a USB interface, an embedded microcontrolleran Analog-to-Digital Interface (ADIF) and an Asynchronous Digital-to-Analog Converter (ADAC).

The USB interface is the interface between the USB,the ADIF, the ADAC and the microcontroller. The USB interface consists of an analog front-end and a USB processor. The analog front-end transforms the differential USB data into a digital data stream. The USB processor buffers the incoming and outgoing data from the analog front-end and handles all low-level USB protocols. The USB processor selects the relevant data from the universal serial bus, performs an extensive error detection and separates control information (input and output) and audio information (input and output). The control information is made accessible to the microcontroller. The audio information received from the PC becomes available at the digital I/O output or is fed directly to the ADAC. The audio information to be transmitted to the PC is delivered by the ADIF or by the digital I²PS-bus interface.

The microcontroller handles the high-level USB protocols, translates the incoming control requests and manages the user interface via general purpose pins and an I²PS-bus.

The firmware for the microcontroller must be located in an external (E)PROM.

The ADAC enables the wide and continuous range of input sampling frequencies. By means of a Sample Frequency Generator (SFG), the ADAC is able to reconstruct the average sample frequency from the incoming audio samples. The ADAC also performs the sound processing. The ADAC consists of a FIFO, a unique audio feature processing DSP, the SFG, digital upsampling filters, a variable hold register, a Noise Shaper (NS) and a Filter Stream DAC (FSDAC) with integrated filter and line output drivers. The audio information is applied to the ADAC via the USB processor or via the digital I/O input.

The ADIF consists of an Programmable Gain Amplifier (PGA), an Analog-to-Digital Converter (ADC) and a Decimator Filter (DF). An Analog Phase Lock Loop (APLL) or oscillator is used for clocking the ADIF. The clock frequency for the ADIF can be controlled via the microcontroller. Several clock frequencies are possible for sampling the analog input signal at different sampling rates.

Via the digital I/O-bus, an external DSP can be used for adding extra sound processing features for the audio received from the PC.

The UDA1335H supports the digital I/O and the I²PS-bus interface, with standard I²PS-bus data input format and the LSB justified serial data input format with word lengths of 16, 18 and 20 bits.

The wide dynamic range of the bitstream conversion technique used in the UDA1335H guarantees a high audio sound quality.

Features

General

• USB stereo audio record and playback system with 20 bits analog-to-digital conversion (with 5 to 55 kHz sample frequency range) and adaptive 20 bits digital-to-analog conversion (with 5 to 55 kHz sample frequency range) with integrated filtering
• USB-compliant audio/HID device
• Supports 12 Mbits/s ?full speed? serial data transmission
• Fully automatic ?Plug-and-Play? operation
• Supports multiple audio data formats (8, 16 and 24 bits)
• 5.0 and 3.3 V power supply
• Low power consumption
• Efficient power management
• On-chip master clock oscillatorsonly an external crystal is required
• High linearity
• Wide dynamic range
• Superior signal-to-noise ratio
• Low total harmonic distortion
• Supports headphone and line output
• Partly programmable USB descriptors and configuration via the I²PC-bus.

Sound processing (for digital-to analog conversion)

• Separate digital volume control for left and right channel
• Soft mute
• Digital bass and treble tone control
• External Digital Sound Processor (DSP) option possible via standard I²S-bus or Japanese digital I/O format
• Selectable clipping prevention
• Selectable Dynamic Bass Boost (DBB)
• On-chip digital de-emphasis.

Document references

• USB Specification
• USB Device Class Definition for Audio Devices
• Device Class Definition for Human Interface Devices (HID)
• USB HID Usage Table
• USB Common Class Specification

Applications

• USB monitors
• USB speakers
• USB headsets
• USB telephone/answering machines
• USB links in consumer audio devices.

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Disclaimers

• General product disclaimer
• Quality and reliability disclaimer