19-5221; Rev 0; 5/10
MAX98500 Evaluation Kit
General Description
The MAX98500 evaluation kit (EV kit) is a fully assembled
and tested circuit board that uses the MAX98500 boost-
ed Class D amplifier to drive a mono bridge-tied-load
(BTL) speaker in portable audio applications. Designed
to operate from a 2.5V to 5.5V DC power supply, the EV
kit delivers 2.2W into an 8I load. The EV kit accepts
differential or single-ended input signals, features three
selectable gain settings (6dB, 15.5dB, and 20dB), and
provides separate speaker and boost shutdown inputs.
Features
S
2.5V to 5.5V Single-Supply Operation
S
Output Power: 2.2W into 8ω, 10% THD+N
S
Selectable Gain Settings (6dB, 15.5dB, and 20dB)
S
Boosted Class D Output
S
Differential or Single-Ended Input Signals
S
Boost Converter Shutdown
S
Speaker Output Shutdown
S
Fully Assembled and Tested
Evaluates: MAX98500
Ordering Information
PART
MAX98500EVKIT+
TYPE
EV Kit
+Denotes
lead(Pb)-free and RoHS compliant.
Component List
DESIGNATION
QTY
DESCRIPTION
10FF
Q10%,
6.3V X7R ceramic
capacitor (0805)
Murata GRM21BR70J106K
TDK C2012X7R0J106K
22FF
Q20%,
16V X5R ceramic
capacitor (1206)
Murata GRM31CR61226M
Taiyo Yuden EMK316BJ226M
1FF
Q10%,
25V X7R ceramic
capacitors (0603)
Murata GRM188R71E105K
Murata GRM188R71E105M
22FF
Q10%,
6.3V X5R ceramic
capacitor (0805)
Murata GRM21BR60J226M
TDK C2012X5R0J226K
0.1FF
Q10%,
16V X7R ceramic
capacitor (0402)
Murata GRM155R71C104K
TDK C1005X7R1C104K
Not installed, ceramic capacitors
(0402)
Not installed, ceramic capacitors
(0603)
DESIGNATION
QTY
DESCRIPTION
0.22FF
Q10%,
25V X7R ceramic
capacitors (0603)
Murata GRM188R71E224K
TDK C1608X7R1E224K
0I resistor (0603)
Not installed, ferrite beads (0603)
Phono jack, black (side-entry
PCB mount)
3-pin headers
2-pin header
2.2FH, 34mI, 4.5A inductor
TOKO FDV0530S-2R2M
(5mm x 5mm x 3mm)
TDK LTF5022T-2R2N3R2-LC
(5mm x 5mm x 2.2mm)
NEC MPLC0525L2R2
(5.2mm x 6.2mm x 2.5mm)
Not installed, inductors
TOKO A916CY-220M (provided
with EV kit)
Test points
27.4kω
Q1%
resistor (0603)
22ω
Q5%
resistors (0603)
REQUIRED COMPONENTS
C14–C18
5
C1
1
FB1
FB2, FB3
J1
JU1, JU2, JU3
JU4
1
0
1
3
1
C2
1
C3, C4
2
L1
1
C5
1
C8
1
L2, L3
OUT-, OUT+,
PGND, RKNEE
R1
R2, R3
0
4
1
2
C9, C10
C12, C13
0
0
_______________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX98500 Evaluation Kit
Evaluates: MAX98500
Component List (continued)
DESIGNATION
U1
VCCOUT
—
—
QTY
1
0
4
1
DESCRIPTION
Boosted Class D amplifier
(16 WLP)
Maxim MAX98500EWE+
Not installed, test point
Shunts
PCB: MAX98500 EVALUATION
KIT+
DESIGNATION
QTY
DESCRIPTION
22FH
Q20%,
0.7A inductors
(D63CB)
TOKO A916CY-220M
OPTIONAL COMPONENTS
L2, L3
2
Component Suppliers
SUPPLIER
Murata Electronics North America, Inc.
NEC TOKIN America, Inc.
TDK Corp.
TOKO America, Inc.
PHONE
770-436-1300
408-324-1790
847-803-6100
847-297-0070
WEBSITE
www.murata-northamerica.com
www.nec-tokinamerica.com
www.component.tdk.com
www.tokoam.com
Note:
Indicate that you are using the MAX98500 when contacting these component suppliers.
Quick Start
•
•
•
2.5V to 5.5V, 4A DC power supply
8I
speaker
Mono audio signal source
5)
6)
7)
8)
Verify that the audio source output is disabled.
Connect the mono audio source between the IN+
and IN- pads or J1 on the EV kit.
Connect the speaker across the OUT+ and OUT-
test points.
Enable the power-supply output.
Enable the audio source.
Recommended Equipment
The MAX98500 EV kit is fully assembled and test-
ed. Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1)
Verify that shunts are installed as follows:
JU1: Open (15.5dB gain)
JU2: Pins 1-2 (speaker enabled)
JU3: Pins 1-2 (boost enabled)
JU4: Short (single-ended/unbalanced input)
Set the power-supply output to 3.6V.
Disable the power-supply output.
Connect the power-supply ground to the PGND pad
and the power-supply positive output to the VBAT
pad on the EV kit. Keep VBAT lengths < 6in and
twisted to minimize inductance, to ensure proper
device operation.
Procedure
9)
10) Verify that the speaker is playing the audio source
signal.
Detailed Description of Hardware
The MAX98500 EV kit features the MAX98500 boosted
Class D amplifier IC, designed to drive a BTL mono
speaker in portable audio applications. The EV kit
accepts a differential or single-ended audio input, fea-
tures three selectable gain settings (6dB, 15.5dB, and
20dB), and provides two active-low shutdown inputs for
flexibility. The audio input source is amplified to drive
2.2W into an 8I speaker. The EV kit operates from a
single DC power supply that provides 2.5V to 5.5V.
The EV kit provides two sets of differential outputs. The
device outputs (OUT+ and OUT-) can be connected
directly to a speaker load without any filtering. However,
a filter can be added to ease evaluation.
2)
3)
4)
2
______________________________________________________________________________________
MAX98500 Evaluation Kit
Evaluates: MAX98500
The MAX98500 features three internal gain settings that
are selectable with the GAIN input. Jumper JU1 controls
the amplifier’s gain select input. See Table 1 for jumper
JU1 configuration.
The MAX98500 features two active-low shutdown inputs
(SDSPK and
SDBST).
Jumper JU2 enables or disables
the speaker amplifier (SDSPK) and jumper JU3 controls
the boost converter (SDBST). See Table 2 for jumpers
JU2 and JU3 configuration. Note that the boost must be
enabled for the speaker amplifier to enable.
Jumper JU4 provides the option to select between a dif-
ferential or single-ended input mode for the EV kit. See
Table 3 for JU4 configuration.
Selectable Gain Setting
The MAX98500 speaker amplifier is designed to pass
FCC emissions standards without any filtering. When
evaluating the MAX98500 without any filtering, connect
the speaker to the output test points (OUT+, OUT-).
The EV kit also features PCB pads for a lowpass filter
that can be added to ease evaluation. Audio analyzers
typically cannot accept the Class D amplifier’s pulse-
width-modulated (PWM) waveform at their inputs. The
lowpass filter extracts the audio content from the PWM
output signal and allows the device to be connected
directly to an audio analyzer. The PWM output signal
can be lowpass-filtered by simply installing L2 and L3;
all other components are populated. The filtered outputs
should then be monitored at the FOUT+/ FOUT- pads.
See Table 4 for suggested filtering components for an
8I load.
Optional Output Filtering
Shutdown Inputs
Input Mode
Table 1. Gain Input (JU1)
SHUNT
POSITION
2-3
Not installed*
1-2
*Default
position.
GAIN PIN
Connected to AGND
Unconnected
Connected to VBAT
GAIN SETTING
(dB)
6
15.5
20
Table 3. Input Mode (JU4)
SHUNT
POSITION
Installed*
IN- PIN
Connected to AGND
Connected to user-
supplied negative
differential output
INPUT MODE
Single-ended/
unbalanced input
Differential input
Not installed
*Default
position.
SPEAKER
STATUS
Off
Off
Off
On
Table 2. Shutdown Configuration
(JU2, JU3)
SDSPK
PIN
(JU2)
2-3 (low)
1-2 (high)
2-3 (low)
1-2* (high)
*Default
position.
SDBST
PIN
(JU3)
2-3 (low)
2-3 (high)
1-2 (low)
1-2* (high)
BOOST
STATUS
Off
Off
On
On
Table 4. Suggested Filtering Components
for 8I Load
DESIGNATION
L2, L3
QTY
2
DESCRIPTION
22FH
Q20%,
0.7A inductor
(D63CB)
TOKO A916CY-220M
_______________________________________________________________________________________
3
MAX98500 Evaluation Kit
Evaluates: MAX98500
Figure 1. MAX98500 EV Kit Schematic
4
______________________________________________________________________________________
MAX98500 Evaluation Kit
Evaluates: MAX98500
1.0”
1.0”
Figure 2. MAX98500 EV Kit Component Placement Guide—
Component Side
Figure 3. MAX98500 EV Kit PCB Layout—Component Side
1.0”
Figure 4. MAX98500 EV Kit PCB Layout—Solder Side
_______________________________________________________________________________________
5
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