Datasheet
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
8 _______________________________________________________________________________________
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.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9744 toc17
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
10
100
0.001
10 100k
PVDD = 12V
R
L
= 8Ω
FILTERLESS MODULATION
P
OUT
= 3W
FFM
SSM
EFFICIENCY vs. OUTPUT POWER
MAX9744 toc18
OUTPUT POWER (W)
EFFICIENCY (%)
POWER DISSIPATION (mW)
1284
10
20
30
40
50
60
70
80
90
100
0
1
2
3
4
5
6
7
8
9
10
0
016
PVDD = 12V, f
IN
= 1kHz, R
L
= 4Ω
FILTERLESS MODULATION
PWM MODE
EFFICIENCY vs. OUTPUT POWER
MAX9744 toc19
OUTPUT POWER (W)
(PER CHANNEL)
EFFICIENCY (%)
POWER DISSIPATION
10624
20
10
40
60
80
30
50
70
90
100
0
5W
0W
08
PWM MODE
FILTERLESS MODULATION
PVDD = 12V
f
IN
= 1kHz
R
L
= 8Ω
EFFICIENCY vs. OUTPUT POWER
MAX9744 toc20
OUTPUT POWER (W)
EFFICIENCY (%)
POWER DISSIPATION
3.01.50.5 1.0
20
10
40
60
80
30
50
70
90
100
0
2W
0W
0 2.0 2.5
PWM MODE
FILTERLESS MODULATION
PVDD = 5V
f
IN
= 1kHz
R
L
= 4Ω
EFFICIENCY vs. SUPPLY VOLTAGE
MAX9744 toc21
SUPPLY VOLTAGE (V)
EFFICIENCY (%)
141068
75
80
85
90
95
100
70
412
f
IN
= 1kHz
R
L
= 4Ω
FILTERLESS MODULATION
THD+N = 10%
THD+N = 1%
EFFICIENCY vs. SUPPLY VOLTAGE
MAX9744 toc22
SUPPLY VOLTAGE (V)
EFFICIENCY (%)
141068
75
80
85
90
95
100
70
412
f
IN
= 1kHz
R
L
= 8Ω
FILTERLESS MODULATION
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9744 toc24
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
121086
4
8
12
16
20
24
0
414
f
IN
= 1kHz
R
L
= 4Ω
PWM MODE
THD+N = 10%
THD+N = 1%
EFFICIENCY vs. SUPPLY VOLTAGE
MAX9744 toc23
SUPPLY VOLTAGE (V)
EFFICIENCY (%)
121086
75
80
85
90
95
100
70
414
f
IN
= 1kHz
R
L
= 4Ω
PWM MODE
THD+N = 10%
THD+N = 1%