Datasheet
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
12 ______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 BOOTL+
Left-Channel Positive Speaker Output Boost Flying-Capacitor Connection. Connect a 0.1µF
ceramic capacitor between BOOTL+ and OUTL+.
2, 3 OUTL+ Left-Channel Speaker Output, Positive Phase
4, 5, 29, 30 PVDD Speaker Amplifier Power-Supply Input. Bypass each with a 1µF capacitor to PGND.
6, 10, 21, 28 V
DD
Power-Supply Input. Bypass each with a 1µF capacitor to GND.
7, 11, 12, 15, 27 GND Ground
8 SDA/VOL I
2
C Serial Data I/O and Analog Volume Control Input
9 SCLK/PWM
I
2
C Serial Clock Input and Modulation Scheme Select. In I
2
C mode (ADDR1 and ADDR2 ≠ GND),
acts as I
2
C serial clock input. When ADDR1 and ADDR2 = GND, set SCLK = 1 for standard PWM
output scheme, or set SCLK = 0 for filterless modulation output scheme.
13 ADDR1
Address Select Input 1. Sets device address for I
2
C address option. Connect ADDR1 and ADDR2
to GND to select analog volume control mode.
14 ADDR2
Address Select Input 2. Sets device address for I
2
C address option. Connect ADDR1 and ADDR2
to GND to select Analog Volume Control mode.
16 INL Left-Channel Audio Input
17 FBL
Left-Channel Feedback. Connect feedback resistor between FBL and INL to set amplifier gain. See
the Gain-Setting Resistors section.
18 FBR
Right-Channel Feedback. Connect feedback resistor between FBR and INR to set amplifier gain.
See the Gain-Setting Resistors section.
19 INR Right-Channel Input
20 BIAS Common-Mode Bias Voltage. Bypass with a 2.2µF capacitor to GND.
22 SHDN
Shutdown Input. Drive SHDN low to disable the audio amplifiers. Connect SHDN to V
DD
or drive
high for normal operation.
23 N.C. No Connection. Not internally connected.
24 MUTE
Mute Input. Drive MUTE high to mute the speaker outputs. Connect MUTE to GND for normal
operation (mute function controls speaker outputs only).
25 SYNC
Frequency Select and External Clock Input.
SYNC = GND: Fixed-frequency mode with f
SYNC
= 1200kHz
SYNC = Unconnected: Fixed-frequency mode with f
SYNC
= 1440kHz
SYNC = V
DD
: Spread-spectrum mode with f
SYNC
= 1200kHz ±30kHz
SYNC = Clocked: Fixed-frequency mode with f
SYNC
= external clock frequency. f
SW
= 1/4 the
value of f
SYNC
.