UAC 355xB is Micronas’ new USB audio IC. It contains a high-performance stereo audio ADC/DAC, digital serial interfaces, and an additional DAC channel for the subwoofer signal.

The UAC 355xB offers a programmable 5-band parametric equalizer for correcting the frequency response of the applied speaker plus adjustable dynamic low-frequency processing for the subwoofer channel. All sampling rates for USB record and playback are handled independently.

The codec functionality of the UAC 355xB is extended by additional interfaces, like I²S, allowing all kinds of digital audio processing systems to be connected to the USB, e. g. Dolby Digital or MP3 decoding chips, such as DPL 4519G/MAS^® 3528E, or MAS^® 35x9F.

General-purpose inputs and outputs connect the UAC 355xB to peripheral hardware such as buttons, keyboards, LEDs etc. Via I²C, more complex peripherals like LCD displays can be controlled.

The UAC 355xB itself can be remote-controlled via I²C in non-USB environments.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.

Micronas supplies a standard ROM firmware based on the USB Composite Class, Audio Class, and HID Class.

Main Features

Single-chip USB 2.0 full-speed compliant stereo audio ADC and DAC

Adaptive isochronous endpoints for playback and record USB Audio

Supports 16-bit mono/stereo and 24-bit stereo for playback (D/A converter)

Supports 8-bit mono and 16-bit mono/stereo, for record (A/D converter)

Generic ISO-playback endpoint (Dolby Digital, MP3)

USB programmable device and configuration descriptor

Bus- or self-powered configurations

Remote wake-up

12 general-purpose I/O pins

I2S input/output interface

independent adaptive sample rates of 6.4 to 48 kHz for USB record and playback (enhanced full-duplex)

Audio baseband control: bass, treble, loudness, volume, balance, and mute

Dynamic bass management (Micronas Dynamic Bass=MDB)

Digital speaker equalizer (5-band parametric equalizer)

Adjustable digital subwoofer filter

THD better than −85 dB and SNR of typ. 96 dB for D/A converters

THD better than −85 dB and SNR of typ. 92 dB for A/D converters

Integrated stereo headphone amplifier

Subwoofer output with internal split filter

I2C interface (master/slave)

Bootable firmware for µC (UAC 3556B)

Customized firmware extensions possible via plug-ins

On-chip analog filters for out-of-band noise suppression

Packages: PQFN64, PMQFP64, and PMQFP44

Versions

	Version	Description
	UAC 3556B	Universal Serial Bus (USB) codec with standard ROM firmware and bootloader for 8-kByte firmware download
	UAC 3554B	mask-programmed version