Datasheet

Detailed Description of Hardware
The MAX9736A EV kit is designed to evaluate the
MAX9736A in a 32-pin TQFN-EP package. The
MAX9736A is a Class D amplifier that can be config-
ured to drive 2 x 15W into a pair of 8Ω speakers, or 1 x
30W into a 4Ω speaker. The EV kit operates from a DC
power supply that provides 8V to 28V and 5A of current.
The EV kit PCB is designed with two layers and has 2oz
copper for optimized power dissipation. The MAX9736A
EV kit accepts a pair of single-ended input signals and
provides two sets of amplified differential audio outputs.
Optional External Preamplifier
Power Supply (VS)
The MAX9736A EV kit provides an input pad to accept
an optional 5V external power supply for powering the
MAX9736A preamplifiers when the internal regulator is
disabled. Disable the internal regulator by removing the
shunt from jumper JU3 before connecting an external
power supply between the VS and AGND pads on the
MAX9736A EV kit (see Table 4). The external power
supply for the preamplifiers must be in the 4.5V to 5.5V
range. Refer to the
Power Sequencing section in the
MAX9736A IC data sheet before operating with optional
external preamplifier power supply.
Filtered Output
Audio analyzers typically cannot accept pulse-width-
modulated (PWM) signals at their inputs. Therefore, the
MAX9736AEV kit features a pair of lowpass filters at
each of the outputs to ease evaluation. Use the filtering
output posts (FOUTL+/FOUTL- and FOUTR+/FOUTR-)
to connect the filtered PWM outputs to the audio ana-
lyzer. The default lowpass filters at the EV kit outputs
are optimized for a pair of 8Ω speakers.
Filterless Output
The MAX9736A EV kit’s filterless outputs (L+/L- and
R+/R-) can be connected directly to a pair of speaker
loads without any filtering. Use the L+/L- and R+/R- test
points to connect speakers directly to the MAX9736A
outputs using twisted-pair cable. Remove inductors
L1–L4 for maximum efficiency.
Output Filtering Requirements
To ease evaluation, the MAX9736A EV kit is shipped with
inductor-based output filters. However, the MAX9736A can
pass EC EN55022 regulations with only ferrite-bead filters,
especially when speaker-wire lengths are less than 1m.
To install the ferrite-bead filters, first remove the large
filter inductors (L1–L4). Next, replace resistors R6–R9
with ferrite beads listed in Table 1 (provided with the EV
kit), and install filter capacitors on the C13–C16 pads.
The speaker wire should be connected to L+, L-, R+,
and R- test points using twisted-pair cable.
Although component selection for the output filter is
dependent on speaker-wire length, the components in
Table 1 are provided with the EV kit as a starting point.
Final component selection should be determined during
EMC testing. Contact the factory if required.
Jumper Selection
Digital Inputs Power Supply (DVDD)
The MAX9736A EV kit operates from a DC power supply
between 8V and 28V. This power-supply range is too high
for the digital input pins on the MAX9736A IC. The EV kit
includes a circuit to regulate the input power supply to 5V
for powering all the logic circuits on the EV kit. Jumper JU1
sets the DVDD voltage (see Table 2 for shunt positions).
Shutdown Mode (SHDN)
The MAX9736A features a shutdown mode to reduce
the quiescent current. Jumper JU2 controls the shut-
down (SHDN) pin of the MAX9736A IC (see Table 3 for
shunt positions).
Evaluates: MAX9736A/MAX9736B
MAX9736A Evaluation Kit
_______________________________________________________________________________________ 3
Table 1. Recommended EMI Filter
Components for 8Ω Loads
COMPONENT DESCRIPTION
R6–R9*
Ferrite beads, 600Ω at 100MHz, 150mΩ DCR,
2A (0805)
Würth 742792040
C13-C16
330pF ±10%, 50V X7R ceramic capacitors
(0603)
Murata GRM188R71H331K or
TDK C1608X7R1H331K
* 3A current-rating ferrite beads are recommended for 4
Ω
load
drive.
Table 2. JU1 Jumper Selection (DVDD)
SHUNT
POSITION
DVDD REGULATED
TO (V)
EV KIT DIGITAL
INPUT POWER
1-2* 5 On
2-3 0 Off
* Default position.
Table 3. JU2 Jumper Selection (SHDN)
SHUNT
POSITION
SHDN PIN
CONNECTED TO
EV KIT FUNCTION
Installed* DVDD EV kit enabled
Not
installed
PGND
(through resistor R14)
Shutdown mode
* Default position.