max9708etntd Maxim Integrated Products, Inc., max9708etntd Datasheet - Page 17

• Manufacturer Part Number: max9708etntd
• Description: Max9708 20w/40w, Filterless, Spread-spectrum, Mono/stereo, Class D Amplifier
• Manufacturer: Maxim Integrated Products, Inc.

Mismatch in the components can cause discrepancies
between the nominal transfer function and actual perfor-
mance. Also, the mismatch of the input resistors (R15,
R17, R19, and R21 in Figure 6) of the summing amplifier
and lowpass filter will cause some high-frequency sound
to be sent to the subwoofer.
The circuit in Figure 6 drives a pair of MAX9708 devices
similar to the circuit in Figure 5. The inputs to the
MAX9708 still require AC-coupling to prevent compro-
mising the click-and-pop performance of the MAX9708.
Figure 5. Multiple Amplifiers Implement a 2.1 Audio System
AUDIO
AUDIO
RIGHT
LEFT
______________________________________________________________________________________
Σ
20W/40W, Filterless, Spread-Spectrum,
HIGHPASS
HIGHPASS
LOWPASS
FILTER
FILTER
FILTER
Mono/Stereo, Class D Amplifier
V
DIGITAL
INR+
INR-
MONO
SYNCIN
MONO
INL+
INL-
SYNCOUT
INR+
INR-
INL+
INL-
The left and right drivers should be at an 8Ω to 12Ω
impedance, whereas the subwoofer can be 4Ω to 12Ω
depending on the desired output power, the available
power-supply voltage, and the sensitivity of the individ-
ual speakers in the system. The four gain settings of
the MAX9708 allow gain adjustments to match the sen-
sitivity of the speakers.
MAX9708
MAX9708
OUTR+
OUTR+
OUTR-
OUTL+
OUTL-
OUTR-
OUTL+
OUTL-
8Ω
FULL-
RANGE
SPEAKER
4Ω OR 8Ω
WOOFER
8Ω
FULL-
RANGE
SPEAKER
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