MAX9737EVKIT+ Maxim Integrated Products, MAX9737EVKIT+ Datasheet - Page 8

• Manufacturer Part Number: MAX9737EVKIT+
• Description: KIT EVAL FOR MAX9737
• Manufacturer: Maxim Integrated Products

Specifications of MAX9737EVKIT+

• Amplifier Type: Class D
• Output Type: 1-Channel (Mono)
• Max Output Power X Channels @ Load: 13W x 1 @ 4 Ohm
• Voltage - Supply: 8 V ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Board Type: Fully Populated
• Utilized Ic / Part: MAX9737
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Mono 7W Class D Amplifier
The MAX9737 features a mute mode where the signal is
attenuated at the speaker and the outputs stop switch-
ing. To mute the MAX9737, drive MUTE low.
The MAX9737 features comprehensive click-and-pop
suppression and precharge circuitry that reduce audi-
ble transients on startup and shutdown. The precharge
circuit enables the amplifier within 10ms without any
clicks or pops. Connect PC between the input resistor
(R
and-pop suppression, use a 0.47µF input coupling
capacitor (C
When output current exceeds the current limit, 4.6A
(typ), the MAX9737 disables the outputs and initiates a
450µs startup sequence. The shutdown and startup
sequence is repeated until the output fault is removed.
Properly designed applications do not enter current-
limit mode unless the output is short circuited or con-
nected incorrectly.
When the die temperature exceeds the thermal-shut-
down threshold, +160°C (typ), the MAX9737 outputs
are disabled. When the die temperature decreases by
30°C, normal operation resumes. Some causes of ther-
mal shutdown are excessively low load impedance,
poor thermal contact between the MAX9737’s exposed
pad and the PCB, elevated ambient temperature, or
poor PCB layout and assembly.
The MAX9737 meets EN55022B EMC radiation limits
with an inexpensive ferrite bead and capacitor filter
when the speaker leads are less than or equal to 1m
(Figure 3). Select a ferrite bead with 100Ω to 600Ω
impedance, and rated for 2A. The capacitor value
varies based on the ferrite bead chosen and the speak-
er lead length. See Figure 2 for the correct connections
of these components.
Table 1. Suggested Values for LC Filter
8
IN
_______________________________________________________________________________________
) and the input capacitor (C
R
L
4
8
(Ω)
IN
).
Applications Information
Filterless Class D Operation
Click-and-Pop Suppression
L1, L2 (µH)
10
15
Thermal Shutdown
IN
). For optimal click-
Mute Function
Current Limit
C1 (µF)
0.47
0.15
Figure 1. MAX9737 Efficiency vs. Class AB Efficiency
Figure 2. Ferrite Bead Filter Configuration
Figure 3. MAX9737 EMI Performance with 1m Twisted-Pair
Speaker Cable
C2, C3 (µF)
0.10
0.15
FB1 AND FB2: WURTH742792040
MAX9737
100
90
80
70
60
50
40
30
20
10
40
35
30
25
20
15
10
0
5
0
0
30
1
2
vs. OUTPUT POWER
C4, C5 (µF)
OUTPUT POWER (W)
FREQUENCY (MHz)
EFFICIENCY
FB1
FB2
MAX9737
3
0.22
0.15
100
4
CLASS AB
5
C1
330pF
EN55022B LIMIT
6
7
C2
330pF
R1, R2 (Ω)
1000
8
10
15