max9744 Maxim Integrated Products, Inc., max9744 Datasheet - Page 23

• Manufacturer Part Number: max9744
• Description: 20w Stereo Class D Speaker Amplifier With Volume Control
• Manufacturer: Maxim Integrated Products, Inc.

Proper layout and grounding are essential for optimum
performance. Use large traces for the power-supply
inputs and amplifier outputs to minimize losses due to
parasitic trace resistance. Large traces also aid in mov-
ing heat away from the package. Proper grounding
improves audio performance, minimizes crosstalk
between channels, and prevents any switching noise
from coupling into the audio signal. Connect PGND and
GND together at a single point on the PCB. Route all
traces that carry switching transients away from GND
and the traces/components in the audio signal path.
Connect all PVDD power supplies together and bypass
with a 1µF capacitor to PGND. Connect all V
supplies together and bypass with a 1µF capacitor to
GND. Place a bulk capacitor between PVDD and PGND
if needed.
______________________________________________________________________________________
Supply Bypassing, Layout,
TOP VIEW
20W Stereo Class D Speaker Amplifier
BOOTR-
BOOTL-
OUTR-
OUTR-
OUTL-
OUTL-
PGND
PGND
PGND
PGND
PGND
and Grounding
34
35
36
37
38
39
41
42
40
43
44
33 32 31 30 29 28 27 26 25 24 23
1
+
DD
2
power
3
4
(7mm x 7mm)
MAX9744
5
TQFN
6
Use large, low-resistance output traces. Current drawn
from the outputs increase as load impedance decreas-
es. High output trace resistance decreases the power
delivered to the load. Large output, supply, and GND
traces allow more heat to move from the MAX9744 to
the air, decreasing the thermal impedance of the circuit.
The MAX9744 thin QFN package features an exposed
thermal pad on its underside. This pad lowers the pack-
age’s thermal resistance by providing a direct heat con-
duction path from the die to the PCB. Connect the
exposed thermal pad to PGND by using a large pad and
multiple vias to the PGND plane. The exposed pad must
be connected to PGND for proper device operation.
7
8
with Volume Control
9
10 11
22
21
20
19
18
17
16
15
14
13
12
SHDN
BIAS
INR
FBR
FBL
INL
GND
ADDR2
ADDR1
GND
V
DD
Pin Configuration
23