UAC 357xB
Universal Serial Bus (USB) Codec
Release Note: Revision bars indicate significant
changes to the UAC 355xB data sheet edition 2DS.
1.1. Features
Main Features
ADVANCE INFORMATION
– Single-chip, USB specification 2.0 compliant, stereo
audio ADC and DAC
– Dual microphone input
– Pseudo-differential line input
– Capless headphone connection
– Output reference for ground noise cancellation
– Supports 8/16-bit mono/stereo recording and up to
24-bit playback
– Supports streaming of compressed audio
(e.g. Dolby Digital, MP3) to external decoders
– Vendor ID, product ID, strings and device configura-
tion with external EEPROM
– Bus-powered or self-powered mode
– 12 GPIO pins with HID support
– I
2
S input/output interface
– Integrated low-power stereo headphone amplifier
– I
2
C interface (master/slave)
– Customized firmware extensions with plug-ins pos-
sible
– PMQFP64-2 package
Audio Features
– Independent adaptive sample rates of 6.4 to 48 kHz
for USB recording and playback (enhanced full-
duplex)
– Audio baseband control: bass, treble, loudness, vol-
ume, balance, and mute
– Dynamic bass management (Micronas Bass MB)
– Digital speaker equalizer
(5-band parametric equalizer)
– THD better than
−90
dB and SNR of typically 96 dB
for D/A converters
– THD better than
−90
dB and SNR of typically 92 dB
for A/D converters
– Power supply rejection ratio >95 dB for analog out-
puts
1. Introduction
The UAC 357xB is a new member of Micronas’ USB
audio IC family. It contains a high-performance stereo
audio ADC/DAC and digital interfaces for audio or con-
trol data.
The audio ADC with direct dual microphone and
pseudo-differential stereo line input makes the
UAC 357xB the ideal solution for all kinds of USB
audio applications. This includes the replacement of
analog sound cards in PCs. Integrated headphone
amplifiers allow direct capless headphone connection.
Therefore, the IC can be employed as a single-chip
headset solution without extra power supply (bus-pow-
ered).
In home stereo applications with PC-link the output
allows noise-reduced coupling to external ground sys-
tems making active ground coupling circuitry obsolete.
Analog input signals can be pseudo-differentially cou-
pled to reduce ground noise problems.
The UAC 357xB offers a programmable 5-band para-
metric equalizer for correcting the frequency response
of the applied speaker. Internal sample rate converters
offer high flexibility in handling all sample rates for
USB upstream and downstream independently.
The UAC 357xB allows all kinds of digital audio pro-
cessing systems to be connected to the USB, e.g.
Dolby Digital or MP3 decoding chips, such as
DPL 4519G, MAS 3530H, or MAS 35x9F.
General-purpose inputs and outputs connect the
UAC 357xB to peripheral hardware, such as buttons,
keyboards, LEDs, etc. Via I
2
C, more complex periph-
erals, such as LCD displays can be controlled. The
UAC 357xB itself can be remote-controlled via I
2
C in
non-USB environments.
Complete firmware plug-in download functionality of
the on-chip microcontroller turns the UAC 357xB into a
customer-specific IC. Micronas supplies standard
ROM firmware based on the USB Composite Class,
Audio Class, and HID Class, supporting general codec
applications and headset applications.
All-in-all, the IC is designed as the ideal connecting
matrix between USB, analog and digital audio input
and output, home stereo, compressed audio, and all
kinds of human interface devices.
1.2. Members of the UAC 357xB family
Version
UAC 3574B
UAC 3575B
UAC 3576B
Description
USB headset
USB codec
USB codec – emulator version with internal
program RAM for firmware download
4
Aug. 20, 2004; 6251-650-1AI
Micronas