Analog Devices
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3
MAX98365 Evaluation Systems
Evaluates: MAX98365A/MAX98365B/
MAX98365C/MAX98365D
Detailed Description of Hardware
The MAX98365 EV system is designed to allow for
a thorough evaluation of the MAX98365 digital input
Class-D audio amplifier IC. The EV system includes the
MAX98365 Development Board (DEV board), the Audio
Interface Board III (AUDINT3), and a micro-USB cable.
To simplify evaluation, the MAX98365 DEV board can be
used together with the AUDINT3 and only one external
power supply for PVDD. The AUDINT3 supplies 1.8V for
VDD and a plug-and-play USB-to-I
2
S interface, allowing
any computer to become a 48kHz digital audio source.
The AUDINT3 board provides a fast and easy-to-use
method for exercising the main capabilities of the device
with no additional audio equipment.
The AUDINT3 board automatically senses the MAX98365
DEV board and configures its LDO regulators to power
the MAX98365 DEV board’s VDD pin through connec-
tor J1. The USB-to-PCM converter accepts a USB audio
stream from a USB connected computer and converts
to I
2
S (MAX98365A/C) or left-justified (MAX98365B/D)
data stream, allowing for USB audio playback through the
MAX98365 device. The AUDINT3 board should not be
used to deliver audio input when directly driving the DEV
board’s PCM interface with external audio test equipment.
The digital audio interface (DAI) pins on the DEV board
and AUDINT3 digital audio outputs are connected through
the J1 header, creating a signal conflict. Disable all DAI
signals using the AUDINT3 software if using external
audio stimuli. However, the AUDINT3 can still provide
VDD if an external power supply is not available.
For maximum flexibility, the MAX98365 DEV board can
also be evaluated as a standalone board, with two exter-
nal power supplies (PVDD and VDD), and the digital audio
signal is driven directly by specialized audio test equip
-
ment (Audio Precision, etc.)
Power Supplies
When evaluated as a standalone board, the MAX98365
DEV board requires two external power supplies: PVDD,
which is the supply voltage for the main Class-D power
stage, and VDD, which supplies low level system power
to the IC.
The voltage applied to VDD determines the logic level of
the EN pin when J6 is in the ENABLE position. The power
supplies and their ranges are listed in
. The exter-
nal supply voltages can be connected at the respective
supply test-points and/or binding posts.
The AUDINT3 board, when properly connected to the DEV
Board, senses, and automatically provides 1.8V to VDD
of MAX98365 DEV Board through jumper J1, when active
USB power is supplied. Note that with the AUDINT3 board
connected, VDD is automatically provided, but an external
PVDD is still required. If an external VDD is desired with
AUDINT3 still connected to the DEV Board, jumper J13
(DEV board) can be used to disconnect the AUDINT3’s
1.8V. See
Jumper Selection
Shutdown Mode
The DEV Board includes header J6 for device enable. The
MAX98365 device features a low-power shutdown mode
that is activated by setting J6 shunt in the “DISABLE”
position. To exit shutdown mode, place J6 shunt to the
“ENABLE” position. When the PCM master is disabled
and J6 is in the “ENABLE” position, the device is in
standby mode. Enabling the PCM interface while J6 is
in the “ENABLE” position puts the device in active play-
back mode, and the device output begins switching. See
Table 1. Power Supplies
Table 3. Jumper Configuration
Table 2. J13 Jumper Selection (VDD)
Supplies
POWER SUPPLY
RANGE (V)
VDD
1.71 to 5.5
PVDD
3 to 14
HEADER
SHUNT POSITION
DESCRIPTION
J6
EN to VDD
Normal operation
EN to GND
Shutdown
SHUNT POSITION
INPUT VOLTAGE (VDD)
1-2
VDD supplied by AUDINT3 board con-
nected to J1 header
OPEN
User-supplied external power supply
applied at VDD and GND test posts
