1998 Aug 28
2
Philips Semiconductors
Preliminary specification
Universal Serial Bus (USB) Audio
Playback Recording Peripheral (APRP)
UDA1335H
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 oscillators, only 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 I
2
C-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 I
2
S-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”
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 microcontroller, an
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 I
2
S-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 I
2
C-bus.