NAU8814
Mono Audio Codec with Speaker Driver and Equalizer
1.
GENERAL DESCRIPTION
emPowerAudio
™
NAU8814 is a cost effective and low power wideband MONO audio CODEC. It is designed for voice telephony
related applications. Functions include 5-band Graphic Equalizer, Automatic Level Control (ALC) with noise gate,
PGA, standard audio interface I2S, PCM with time slot assignment, and on-chip PLL. The device provides one
differential microphone input and one single ended auxiliary input (multi purpose). There are few variable gain control
stages in the audio path. It also includes MONO line output and integrated BTL speaker driver.
The analog inputs have PGA on the front end, allowing dynamic range optimization with a wide range of input
sources. The microphone amplifiers have a programmable gain from -12dB to +35.25dB to handle both amplified
microphones. In addition to a digital high pass filter to remove DC offset voltages, the ADC also features voice band
digital filtering. Voice band data is accepted by the audio interface (I2S). The DAC converter path includes filtering
and mixing, programmable-gain amplifiers (PGA), and soft muting.
The digital interfaces, 2-Wire or SPI, have
independent supply voltage to allow integration into multiple supply systems. NAU8814 operates at supply voltages
from 2.5V to 3.6V, although the digital core can operate at voltage as low as 1.71V to save power.
2.
FEATURES
Low Power, Low Voltage
Analog Supply: 2.5V to 3.6V
Digital Supply: 1.71V to 3.6V
Nominal Operating Voltage: 3.3V
Additional features
5-band Graphic Equalizer
Programmable ALC
ADC Notch Filter
Programmable High Pass Filter
Digital A/D-D/A Passthrough
AEC-Q100 & TS16949 qualification
Industrial temperature: range: –40C to +85C
Applications
VoIP Telephones]
Conference speaker-phone
IP PBX
Mobile Telephone Hands-free Kits
Residential & Consumer Intercoms
24-bit signal processing linear Audio CODEC
Audio DAC: 93dB SNR and -84dB THD
Audio ADC: 91dB SNR and -79dB THD
Support variable sample rates from 2.5 - 48kHz
Integrated BTL Speaker Driver 1 W (8Ω / 5V)
Integrated Headset Driver 40mW (16Ω / 3.3V)
Analog I/O
Integrated programmable Microphone Amplifier
Integrated Line Input and Line Output
Earphone / Speaker / Line Output selection
Microphone / Line Inputs selection
Low Noise bias supplied for microphone
On-chip PLL
Interfaces
2
I S digital interface PCM time slot assignment
2
SPI & 2-Wire serial control Interface (I C style;
/Write capable)
Line Driver
AUX
Microphone
Interface
ADC Filter
Input
Mixers
&
Gain
Stage
AUX
DAC Filter
Output
Mixers
ADC
Volume
Control
HPF
MIC-
MIC+
Volume
Control
Limiter
DAC
&
Speaker
Volume
-1
BTL
Speaker
Driver
SPK+
SPK-
Notch Filter
PLL
EQUALIZER
MICBIAS
Micophone
Bias
GPIO
Digital Audio Interface
IS
2
Serial Control Interface
2-wire
SPI
PCM
CSb/GPIO
Audio I/O
Digital I/O
emPowerAudio
™
Datasheet Revision 2.0
Page 1 of 107
January 2011
NAU8814
6.
Table of Contents
1.
GENERAL DESCRIPTION
.................................................................................................................................1
2.
FEATURES
......................................................................................................................................................... 1
3.
PIN CONFIGURATION
.......................................................................................................................................2
4.
PIN DESCRIPTION
.............................................................................................................................................3
5.
BLOCK DIAGRAM
.............................................................................................................................................4
6.
TABLE OF CONTENTS
......................................................................................................................................5
7.
LIST OF FIGURES
..............................................................................................................................................9
8.
LIST OF TABLES
............................................................................................................................................. 11
9.
ABSOLUTE MAXIMUM RATINGS
................................................................................................................... 12
10.
OPERATING CONDITIONS
.............................................................................................................................. 12
11.
ELECTRICAL CHARACTERISTICS
................................................................................................................ 13
12.
FUNCTIONAL DESCRIPTION
.......................................................................................................................... 16
12.1. INPUT PATH
.............................................................................................................................................. 16
12.1.1. The Single Ended Auxiliary Input (AUX)
......................................................................................... 16
12.1.2. The differential microphone input (MIC- & MIC+ pins)...................................................................
18
12.1.2.1.
12.1.2.2.
Positive Microphone Input (MIC+)
........................................................................................... 19
Negative Microphone Input (MIC-)
........................................................................................... 19
12.1.2.3. PGA Gain Control
..................................................................................................................... 20
12.1.3. PGA Boost Stage
.............................................................................................................................. 20
12.2. MICROPHONE BIASING
........................................................................................................................... 22
12.3. ADC DIGITAL FILTER BLOCK
................................................................................................................. 24
12.3.1. Programmable High Pass Filter (HPF)
............................................................................................ 25
12.3.2. Programmable Notch Filter (NF)
...................................................................................................... 25
12.3.3. Digital ADC Gain Control
.................................................................................................................. 26
12.4. PROGRAMMABLE GAIN AMPLIFIER (PGA)
.......................................................................................... 26
12.4.1. Automatic level control (ALC)
.......................................................................................................... 26
12.4.1.1.
Normal Mode
............................................................................................................................. 29
12.4.1.2. ALC Hold Time (Normal mode Only) .......................................................................................... 29
12.4.2. Peak Limiter Mode
............................................................................................................................ 30
12.4.3. Attack Time
........................................................................................................................................ 31
12.4.4. Decay Times
...................................................................................................................................... 31
12.4.5. Noise gate (normal mode only)
........................................................................................................ 31
12.4.6. Zero Crossing
.................................................................................................................................... 32
12.5. DAC DIGITAL FILTER BLOCK
................................................................................................................. 33
12.5.4. Hi-Fi DAC De-Emphasis and Gain Control
...................................................................................... 34
12.5.5. Digital DAC Output Peak Limiter
..................................................................................................... 35
12.5.6. Volume Boost
.................................................................................................................................... 35
12.5.7. 5-Band Equalizer
............................................................................................................................... 36
12.6. ANALOG OUTPUTS .................................................................................................................................. 37
12.6.1. Speaker Mixer Outputs
..................................................................................................................... 37
12.6.2. MONO Mixer Output
.......................................................................................................................... 38
12.6.3. Unused Analog I/O
............................................................................................................................ 39
12.7. GENERAL PURPOSE I/O
......................................................................................................................... 40
emPowerAudio
™
Datasheet Revision 2.0
Page 5 of 107
January 2011
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