Power Supplies - Analog Devices MAX98366 Series User Manual

MAX98366 Evaluation System
Evaluation Board User Guide
Figure 2. AUDINT3 as Playback Device
Detailed Description of Hardware
The MAX98366 EV system is designed to thoroughly evaluate the MAX98366 digital input Class-D audio amplifier IC.
The EV system includes the MAX98366 Development Board (DEV board), the Audio Interface Board III (AUDINT3), and
a micro-USB cable.
To simplify evaluation, the MAX98366 DEV board can be used together with the AUDINT3 and only one external power
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supply for PVDD. The AUDINT3 supplies 1.8V for VDD and a plug-and-play USB-to-I 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 MAX98366 DEV board and configures its LDO regulators to power the
MAX98366 DEV board's VDD pin through connector J1. The USB-to-PCM converter accepts a USB audio stream from
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a USB-connected computer and converts to I S (MAX98366A/C) or left-justified (MAX98366B/D) data stream, allowing
for USB audio playback through the MAX98366 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.
For maximum flexibility, the MAX98366 DEV board can also be evaluated as a standalone board, with two external power
supplies (PVDD and VDD), and the digital audio signal is driven directly by specialized audio test equipment (Audio
Precision, etc.)

Power Supplies

When evaluated as a standalone board, the MAX98366 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 Table 1. The external supply voltages can be connected at the respective supply test points
and/or binding posts.
Table 1. Power Supplies
POWER SUPPLY VOLTAGE RANGE (V)
VDD 1.71 to 5.5
PVDD 3 to 15
The AUDINT3 board, when properly connected to the DEV board, senses, and automatically provides 1.8V to VDD of
MAX98366 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
Table 2 for the J13 jumper selection.
Table 2. VDD Supply Selection Jumper J13
J13 SHUNT POSITION DESCRIPTION
1-2 VDD supplied by AUDINT3 (through J1)
OPEN External power supply applied at VDD and GND test posts
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