19-6275; Rev 0; 4/12
MAX98502 Evaluation Kit
Evaluates: MAX98502
General Description
The MAX98502 evaluation kit (EV kit) is a fully assembled
and tested circuit board that uses the MAX98502 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 is capable of delivering 2.2W into an 8I load or 4W
into a 4I load. The EV kit accepts differential or single-
ended input signals, features selectable gain, and sepa-
rate speaker and boost shutdown inputs.
S
2.5V to 5.5V Single-Supply Operation
S
4W Mono Class D Output
S
Selectable Gain: +6dB, +15.5dB, and +20dB
S
Boosted Class D Output
S
Differential or Single-Ended Input
S
Boost Converter Shutdown
S
Speaker Output Shutdown
S
Proven PCB Layout
S
Fully Assembled and Tested
Ordering Information
appears at end of data sheet.
Features
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 GRM31CR61C226M
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 (0603)
0.22FF
Q10%,
25V X7R ceramic
capacitors (0603)
Murata GRM188R71E224K
TDK C1608X7R1E224K
DESIGNATION
FB2, FB3
J1
JU1, JU2, JU3
JU4
L1
L2, L3
OUT-, OUT+,
RKNEE, PGND
R1
R2, R3
U1
VCCOUT
—
—
QTY
0
1
3
1
1
0
4
1
2
1
0
4
1
DESCRIPTION
Not installed, ferrite beads
(0603)
Phono jack, black
(side-entry PCB mount)
3-pin headers
2-pin header
2.2FH, 91mI, 1.5A inductor
(3.2mm x 2.5mm)
Murata LQH32PN2R2NN0
Not installed, inductors
Test points
27.4kI
Q1%
resistor (0603)
22I
Q5%
resistors (0603)
Boosted Class D audio
amplifier (16 WLP)
Maxim MAX98502EWE+
Not installed, test point
Shunts
PCB: MAX98502 EVALUATION
KIT
22FH
Q20%,
2A inductors
(D75LC)
TOKO B1047AS-220M
C1
1
C2
1
C3, C4
2
C5
1
C8
1
C12, C13
0
OPTIONAL COMPONENTS
L2, L3
2
C14–C18
5
_________________________________________________________________
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.
MAX98502 Evaluation Kit
Evaluates: MAX98502
Component Suppliers
SUPPLIER
Murata Electronics North America, Inc.
Taiyo Yuden
TDK Corp.
TOKO America, Inc.
PHONE
770-436-1300
800-348-2496
847-803-6100
847-297-0070
WEBSITE
www.murata-northamerica.com
www.t-yuden.com
www.component.tdk.com
www.tokoam.com
Note:
Indicate that you are using the MAX98502 when contacting these component suppliers.
Quick Start
•
MAX98502 EV kit
• 8I
or 4I speaker
• Mono audio signal source
The EV kit is fully assembled and tested. 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)
2) Set the power-supply output to 3.6V.
3) Disable the power-supply output.
4) Connect the power-supply ground to the PGND PCB
pad and the power-supply positive output to the
VBAT PCB pad on the EV kit. Keep VBAT lengths <
8in (and twisted to minimize inductance) to ensure
proper device operation.
5) Verify that the audio source output is disabled.
6) Connect the mono audio source between the IN+ and
IN- PCB pads or J1 on the EV kit.
7) Connect the speaker across the OUT+ and OUT- test
points.
8) Enable the power-supply output.
9) Enable the audio source.
10) Verify that the speaker is playing the audio source
signal.
Detailed Description of Hardware
The MAX98502 EV kit features the MAX98502 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, features three
selectable gain settings, and provides two active-low
shutdown inputs for flexibility. The audio input source is
amplified to drive 2.2W into an 8I speaker or 4W into an
4I speaker. The EV kit operates from a single DC power
supply that can provide 2.5V to 5.5V.
The EV kit provides two sets of differential outputs. The
device outputs (OUT+/OUT-) can be connected directly
to a speaker load, without any filtering, with up to 24in of
cable. However, a filter can be added to ease evaluation.
The IC 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 JU1 con-
figuration.
Recommended Equipment
• 2.5V to 5.5V, 4A DC supply
Procedure
Selectable Gain Setting
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
The IC 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 JU2 and JU3
configuration. The boost must be enabled for the speaker
amplifier to enable.
Shutdown Inputs
_________________________________________________________________
Maxim Integrated Products
2
MAX98502 Evaluation Kit
Evaluates: MAX98502
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.
Input Mode
The IC is designed to pass FCC emissions standards
without any filtering when using up to 24in of cable to
connect the speaker. When evaluating the IC 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 typi-
cally cannot accept the Class D amplifier’s pulse-width-
modulated (PWM) waveform at their inputs. The lowpass
Optional Output Filtering
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.
Contact the factory for suggested filtering components
for a 4I load.
The EV kit can be used to drive a 4I or 8I load. See
tables 5 and 6 below for required components for each
load.
Optional Output Loading
Table 2. Shutdown Configuration
(JU2, JU3)
SDBST
PIN
(JU3)
2-3 (low)
2-3 (low)
1-2 (high)
1-2* (high)
*Default position.
SDSPK
PIN
(JU2)
2-3 (low)
1-2 (high)
2-3 (low)
1-2* (high)
BOOST
STATUS
Off
Off
On
On
SPEAKER
STATUS
Off
Off
Off
On
Table 4. Suggested Filtering Components
for 8I Load
DESIGNATION
L2, L3
QTY
2
DESCRIPTION
22FH
Q20%,
2A inductors
(D75LC)
TOKO B1047AS-220M
Table 5. Components Required for 4I
Speaker Drive
DESIGNATION
C5
QTY
1
1
DESCRIPTION
22FF, 6.3V ceramic capacitor
(0805)
0.1FF, 6.3V ceramic capacitor
(0402)
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
C8
Not installed
*Default position.
Table 6. Minimum Components Required
for 8I Speaker Drive
DESIGNATION
C5
C8
QTY
1
1
DESCRIPTION
22FF, 6.3V ceramic capacitor
(0603)
Not installed, ceramic capacitor
_________________________________________________________________
Maxim Integrated Products
3
MAX98502 Evaluation Kit
Evaluates: MAX98502
Figure 1. MAX98502 EV Kit Schematic
_________________________________________________________________
Maxim Integrated Products
4
MAX98502 Evaluation Kit
Evaluates: MAX98502
1.0”
1.0”
Figure 2. MAX98502 EV Kit Component Placement Guide—
Component Side
Figure 3. MAX98502 EV Kit PCB Layout—Component Side
1.0”
Figure 4. MAX98502 EV Kit PCB Layout—Solder Side
_________________________________________________________________
Maxim Integrated Products
5
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