Nuvoton NAU8224 User manual

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
NAU8224 Evaluation Board User Manual
NAU8224 Evaluation kit contents:
1. NAU8224 Evaluation Board (EVB)
2. NAU-ES_MINI_USB –USB to 2-wire interface dongle
3. USB cable
4. GUI installation disc.

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
1. General Description
The NAU8224 is a stereo high efficiency filter-free Class-D audio amplifier, which is capable of
driving a 4Ω load with up to 3W output power. This device provides chip enable pin with
extremely low standby current and fast start-up time. The ability to configure with either
single-ended or differential inputs is included. The NAU8224 has four selectable gain settings of
0dB, 6dB, 12dB, 18dB and 24dB, which can be controlled by a single gain pin. The NAU8224
also has the provision for finer volume control using the 2-wire bus (I2C style) and the bundled
GUI. With
87dB PSRR, 91% efficiency, ultra low quiescent current (i.e. 2.1mA at 3.7V for 2 channels) and
superior EMI performance the NAU8224 is ideal for the portable applications of battery drive.
2. GUI installation procedure
The following steps will describe the installation procedure for the GUI
1. Select the installation package, NAU8224SetupVx.x.EXE,the current version is 1.1
2. The installation will commence and the following screen appears. Click Next.

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
3. The next step is to select the installation directory location. You can use the default location or
select a different location using the Browse button and setting the path. Once done, click on
Next.

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
4. Click the Next button to continue the installation process.
5. The installer will now begin installation procedure and the following progress bar will be
displayed. Once done click on the Next button.

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
6. Click on Finish to complete the installation and exit.

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
7. The GUI will appear under Nuvoton ClassD under All Programs. Click on NAU8224 to launch
the GUI.
3. EVB Set Up

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
Power Connection
An external DC Voltage supply with a compliance of at least 2 Amperes should be connected to J17 &
J23. The supply leads should be kept short in order to avoid I x R supply voltage drop at the amplifier.
Jumper Settings
Install J25 on Pins 1-2 to turn ON the device, installing it on 2-3 turns the device OFF.
J21 is for Gain setting. J21 open means setting the gain of the device to 0dB.
Installing a jumper in the following pins sets the gain of the device as follows:
5-4: (Center –Right Pin) 6dB
5-3: (Center –Top Pin) 12dB
5-2: (Center -- Left Pin) 18dB
5-1: (Center –Bottom Pin) 24dB.
Install J20 for enabling the 2 wire interface volume control via the USB using the bundled dongle in the
kit.
Input Connection
Jumpers J26 and J27 are for selecting the input configuration mode to either, single ended (install
jumpers) or differential (no jumpers installed).
Output Connection
An 8 ohm 68uH load should be connected on each channel (J3- J7) and (J4 - J8). Connect the outputs
to the inputs of the Audio Precision Analyzer (Balanced) via the AP0025 Aux Filter.
Power Up
For optimum performance the board should be power up with J25 in the power down state. Once the
power is applied J25 can be set to power up the board. Then, the input signal can be applied.
Important note:

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
When using a power supply, it is recommended to use a 330µF capacitor across the power pins to
suppress any supply glitches, as a safety measure. When a battery is used, the capacitor is
not required. In normal applications too, the capacitor is not required.
2 wire interface header
The EVB has a 10 pin header which includes a 2 wire interface to control the volume for finer gain
settings. The section of the schematic is shown above. In order to be able to control volume using this
interface, J20 jumper must be installed. This connects the header to the NAU8224 volume control pins.
Pin 3 is a GPIO pin which connects to the enable (EN) pin of the chip. Pins 5 and 7 are the serial Data
and Serial clock lines. An external 2-wire master can be used to send the commands. The bundled
USB dongle could be used to control the volume using the NAU8224 GUI. Pin 10 is the ground pin.
J20
HEADER 2
1
2
VDDA
J24
HEADER5X2X100
1 2
3 4
5 6
7 8
910
R21 2.2
R14 47k
TP17 USB Connector
Male
R17
100
USBVDD Jumper
SCLK
TP16
R18
100
VDDA
SDIO
GPIO
C29
1nF
R15 47k

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
4. Schematic:

NAU8224
NAU8224 User Manual April, 2016
Rev 1.0
5. NAU8224 GUI
The NAU8224 evaluation kit comes along with the NAU-ES_MINI_USB dongle and GUI to control the
volume.
The GUI has just a single screen and has a very simple layout. Once installed the GUI shows up as
below
The first step is to hit the Power Up button. This will ensure any changes in the register settings are
written to the register map of the chip.
The register map shows the two main registers for the Gain and Volume control. The Gain register
address is 0x04 and is a read only register and gets updated depending up the jumper setting of J25.
The volume control register VOLCTRL has address 0x1B and is a read/write register. The value can
1
2
3