MAX9736AEVKIT+ Maxim Integrated Products, MAX9736AEVKIT+ Datasheet - Page 16

• Manufacturer Part Number: MAX9736AEVKIT+
• Description: Audio Modules & Development Tools MAX9736A KIT MAX9736A KIT
• Manufacturer: Maxim Integrated Products

Specifications of MAX9736AEVKIT+

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

reduces the efficiency, the THD+N performance, and
the output power of the MAX9736. When evaluating
with a load speaker, no series inductor is required.
Some applications use the MAX9736 with a full induc-
tor-/capacitor-based (LC) output filter. Select the PWM
output mode for best audio performance. See Figure 4
for the correct connections of these components.
The load impedance of the speaker determines the fil-
ter component selection (see Table 1).
Inductors L1 and L2, and capacitor C1 form the prima-
ry output filter. Capacitors C2 and C3 provide common-
mode filtering to reduce radiated emissions. Capacitors
C4 and C5, plus resistors R1 and R2, form a Zobel at
the output. A Zobel corrects the output loading to com-
pensate for the rising impedance of the loudspeaker.
Without a Zobel the filter exhibits a peak response near
the cutoff frequency.
External feedback resistors set the gain of the
MAX9736. The output stage provides a fixed internal
gain in addition to the externally set input stage gain.
For the MAX9736A/D, the fixed output-stage gain is set
at 17dB (7V/V). For the MAX9736B, the fixed output-
stage gain is set at 13.6dB (4.8V/V). Set overall gain by
using resistors R
where A
between 10kΩ and 50kΩ.
The FB terminal is an op amp output and the IN termi-
nal is the op amp inverting input, allowing the MAX9736
to be configured as a summing amplifier, a filter, or an
equalizer.
Mono/Stereo High-Power Class D Amplifier
16
Table 1. Suggested Values for LC Filter
______________________________________________________________________________________
R
L
16
V
4
8
(Ω)
MAX
MAX
is the desired voltage gain. Choose R
9736
9736
F
Inductor-Based Output Filters
and R
B
A D A
:
A
IN
L1, L2 (µH)
V
:
=
(Figure 5 ) as follows:
V
Component Selection
10
15
33
−
=
4 8
.
−
Gain-Setting Resistors
7 1
⎛
⎝ ⎜
.
R
R
⎛
⎝ ⎜
IN
F
R
R
⎞
⎠ ⎟
IN
F
V V
⎞
⎠ ⎟
V V
C1 (µF)
0.47
0.15
0.10
F
An input capacitor, C
resistor, R
that removes the DC bias from an incoming signal. The
AC-coupling capacitor allows the amplifier to automati-
cally bias the signal to an optimum DC level. Assuming
zero-source impedance, the -3dB point of the highpass
filter is given by:
Choose C
cy of interest. Use capacitors whose dielectrics have low
voltage coefficients. Capacitors with high-voltage coeffi-
cients cause increased distortion close to f
COM is the output of the internally generated DC bias
voltage. Bypass COM with a 1μF capacitor to AGND.
The MAX9736 features separate supplies for signal and
power portions of the device, allowing for the optimum
combination of headroom, power dissipation, and noise
immunity. The speaker amplifiers are powered from
PVDD and can range from 8V to 28V. The remainder of
the MAX9736 is powered by VS.
During power-up and power-down, VS must not exceed
PVDD. VS greater than PVDD will damage the device.
Figure 5. Setting Gain
AUDIO
INPUT
C2, C3 (µF)
0.10
0.15
0.10
C
IN
IN
IN
R
so that f
IN
, of the MAX9736 forms a highpass filter
C
COM
R
f
-3dB
−
F
3
dB
C4, C5 (µF)
IN
COM
, in conjunction with the input
is well below the lowest frequen-
FB_
=
IN_
0.22
0.15
0.10
2π
Power-Supply Sequencing
R C
IN IN
1
MAX9736
Power Supplies
Input Capacitor
COM Capacitor
-3dB
R1, R2 (Ω)
OUT_+
OUT_-
.
10
15
33