max9773etgt Maxim Integrated Products, Inc., max9773etgt Datasheet - Page 17

• Manufacturer Part Number: max9773etgt
• Description: Max9773 1.8w, Filterless, Ultra-low Emi, Stereo Class D Audio Power Amplifier
• Manufacturer: Maxim Integrated Products, Inc.

Low frequencies are summed through a two-pole low-
pass filter and sent to the MAX9705 mono speaker
amplifier. The passband gain of the lowpass filter is
unity for in-phase stereo signals:
where R1 = R2 and R3 = R1//R2. The cutoff frequency
of the lowpass filter is set by the following equation:
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 moving
heat away from the package. Proper grounding improves
audio performance, minimizes crosstalk between chan-
nels, and prevents any switching noise from coupling into
the audio signal. Connect PGND and GND together at a
single point on the PC board. Route all traces that carry
switching transients away from GND and the traces/com-
ponents in the audio signal path.
Supply Bypassing, Layout, and Grounding
f
LP
=
2
1
π
×
______________________________________________________________________________________
A
VLP =
C
1
Stereo Class D Audio Power Amplifier
×
C
− ×
2
2
×
R
1
1
R
R
3
3
×
R
1.8W, Filterless, Ultra-Low EMI,
4
Bypass V
with a 10µF capacitor to PGND. Place the bypass
capacitors as close to the MAX9773 as possible. Use
large, low-resistance output traces. Current drawn from
the outputs increases as load impedance decreases.
High-output trace resistance decreases the power deliv-
ered to the load. Large output, supply, and GND traces
allow more heat to move from the MAX9773 to the air,
decreasing the thermal impedance of the circuit.
The MAX9773 thin QFN-EP package features an
exposed thermal pad on its underside. This pad lowers
the package’s thermal impedance by providing a direct
heat conduction path from the die to the PC board.
Connect the exposed thermal pad to the GND plane.
For the latest application details on UCSP construction,
dimensions, tape carrier information, printed circuit board
techniques, bump-pad layout, and recommended reflow
temperature profile, as well as the latest information on
reliability testing results, refer to Application Note:
UCSP—A Wafer-Level Chip-Scale Package available on
Maxim’s website at www.maxim-ic.com/ucsp.
UCSP Applications Information
DD
with a 0.1µF capacitor to GND and PV
DD
17