NAU8812EVB Nuvoton Technology Corporation of America, NAU8812EVB Datasheet - Page 34

• Manufacturer Part Number: NAU8812EVB
• Description: BOARD EVAL FOR NAU8812
• Manufacturer: Nuvoton Technology Corporation of America
• Series: emPowerAudio™r

Specifications of NAU8812EVB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The NAU8812 also has a Soft Mute function, which gradually attenuates the volume of the digital signal to zero.
When removed, the gain will ramp back up to the digital gain setting. This function is disabled by default. This
feature provides a tool that is useful for using the DACs without introducing pop and click sounds. To play back an
audio signal, it must first be disabled by setting the DACMT[6] address (0x0A) bit to LOW.
The output of the DAC can be muted by the analog auto mute function. The auto mute function is enabled by setting
AUTOMT[2] address (0x0A) to HIGH and applied to the DAC output when it sees 1024 consecutive zeros at its input.
If at any time there is a non-zero sample value, the DAC will be un-muted, and the 1024 count will be reinitialized to
zero.
The sampling rate of the DAC is determined entirely by the frequency of its input clock and the oversampling rate
setting. The oversampling rate of the DAC can be changed to 64x or 128x. In the 128x oversampling mode it gives
an improved audio performance at slightly higher power consumption. Because the additional supply current is only
1mA, in most applications the 128x oversampling is preferred for maximum audio performance.
The polarity of the DAC output signal can be changed as a feature sometimes useful in management of the audio
phase. This feature can help minimize any audio processing that may be otherwise required as the data are passed
to other stages in the system.
The effective output audio volume of the DAC can be changed using the digital volume control feature. This
processes the output of the DAC to scale the output by the amount indicated in the volume register setting. Included
is a “digital mute” value which will completely mute the signal output of the DAC. The digital volume setting can
range from 0dB through -127dB in 0.5dB steps.
Digital audio pass-through allows the output of the ADC to be directly sent to the DAC as the input signal to the DAC
for DAC output. In this mode of operation, the external digital audio signal for the DAC will be ignored. The pass-
through function is useful for many test and application purposes, and the DAC output may be utilized in any way that
is normally supported for the DAC analog output signals.
The NAU8812 has Hi-Fi DAC gain control for signal conditioning. The level of attenuation for an eight-bit code X is
given by:
It includes on-chip digital de-emphasis and is available for sample rates of 32 kHz, 44.1 kHz, and 48 kHz. The digital
de-emphasis can be enabled by setting DEEMP[5:4] address (0x0A) bits depending on the input sample rate. The
emPowerAudio
Datasheet Revision 2.0
12.5.1. DAC Soft Mute
12.5.2. DAC Auto Mute
12.5.3. DAC Sampling / Oversampling rate, Polarity, DAC Volume control and Digital Pass-through
12.5.4. Hi-Fi DAC De-Emphasis and Gain Control
™
0.5 × (X-255) dB
for 1 ≤ X ≤ 255;
Page 34 of 109
MUTE for X = 0
NAU8812
January 2011