Datasheet

MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
10 ______________________________________________________________________________________
OUTPUT WAVEFORM
(FILTERLESS MODULATION)
MAX9744 toc33
1μs/div
2V/div
2V/div
OUTPUT WAVEFORM (PWM)
MAX9744 toc34
1μs/div
2V/div
2V/div
OUTPUT FREQUENCY SPECTRUM
MAX9744 toc35
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)
15105
-120
-100
-80
-60
-40
-20
0
-140
020
FFM MODE
V
IN
= -60dBV
f = 1kHz
R
L
= 4Ω
UNWEIGHTED
LEFT
RIGHT
OUTPUT FREQUENCY SPECTRUM
MAX9744 toc36
FREQUENCY (kHz)
OUTPUT
MAGNITUDE
(dBV)
15105
-120
-100
-80
-60
-40
-20
0
-140
020
SSM MODE
V
IN
= -60dBV
f = 1kHz
R
L
= 4Ω
UNWEIGHTED
LEFT
RIGHT
WIDEBAND OUTPUT SPECTRUM
(FIXED-FREQUENCY MODULATION MODE)
MAX9744 toc37
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
101
-100
-80
-60
-40
-20
0
20
-120
0 100
RBW = 1kHz
INPUT AC GROUNDED
FILTERLESS MODULATION
WIDEBAND OUTPUT SPECTRUM
(FIXED-FREQUENCY MODULATION MODE)
MAX9744 toc38
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
101
-100
-80
-60
-40
-20
0
20
-120
0 100
RBW = 1kHz
INPUT AC GROUNDED
PWM MODE
WIDEBAND OUTPUT SPECTRUM
(SPREAD-SPECTRUM MODULATION MODE)
MAX9744 toc40
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
101
-100
-80
-60
-40
-20
0
20
-120
0 100
RBW = 1kHz
INPUT AC GROUNDED
PWM MODE
WIDEBAND OUTPUT SPECTRUM
(SPREAD-SPECTRUM MODULATION MODE)
MAX9744 toc39
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
101
-100
-80
-60
-40
-20
0
20
-120
0 100
RBW = 1kHz
INPUT AC GROUNDED
FILTERLESS MODULATION
Typical Operating Characteristics (continued)
(V
PVDD
= 12V, V
DD
= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_- with an inductor in series, 8Ω load, L = 68µH, 4Ω load, L= 33µH. R
L
= ∞, unless otherwise stated, C
BIAS
= 2.2µF,
C
IN
= 0.47µF, R
IN
= 20kΩ, R
F_
= 20kΩ, spread-spectrum mode, T
A
= +25°C, unless otherwise noted.)