MAX98304 Evaluation Kit

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*Default position.

*Default position.

Table 2. Shutdown (JU2)

Table 3. Gain Setting (JU3)

Shutdown

JU2 enables or disables the audio speaker amplifier. See

Table 2 for JU2 configuration.

Gain Setting

The EV kit maximum signal gain can be configured to

five different settings. JU3 selects the overall gain for the

EV kit. See Table 3 for JU3 configuration.

Filtered Output

Audio analyzers typically cannot accept pulse-width-

modulated (PWM) signals at their inputs. Therefore, the

EV kit features the option to install a lowpass filter at its

outputs to ease evaluation. OUT+ and OUT- are shorted

to FOUT+ and FOUT-. The trace must be broken at L1

and L2 before installing inductors L1 and L2 (provided

with the EV kit). The filter components (C7–C11, R3, and

R4) are provided with the EV kit and must be installed

prior to operation. Use FOUT+ and FOUT- to connect the

filtered PWM outputs to an audio analyzer. The default

lowpass filter at the EV kit outputs is optimized for an 8I

speaker. Contact the factory for the 4I speaker filter.

The IC can pass CE EN55022B regulations with 60cm

of speaker cable and no filtering. However, ferrite-bead

filters can be used to achieve further attenuation of radi-

ated emissions. To install the ferrite-bead filters, replace

shorting resistors FB1 and FB2 with 0603 or smaller

ferrite beads and install filter capacitors on the C5 and

C6 pads. The speaker wire should be connected to the

FOUT+ and FOUT- pads.

Filterless Output

The EV kit’s filterless outputs (OUT+ and OUT-) can be

connected directly to a speaker load without any filtering.

Use the OUT+ and OUT- test points or the FOUT+ and

FOUT- pads to connect a speaker directly to the IC out-

puts. Inductors L1 and L2 are not installed for maximum

efficiency.

SHUNT

POSITION

SHDN PIN

AMPLIFIER

1-2*

Connected to PVDD

Enabled

2-3

Connected to PGND

Disabled

SHUNT

POSITION

GAIN PIN

MAXIMUM

GAIN (dB)

Open

Not connected

0

1-2

Connected to PVDD

through R1

+3

1-3

Connected to PVDD

+6

1-4

Connected to PGND

through R2

+9

1-5*

Connected to PGND

+12