General Description
The MAX9700B evaluation kit (EV kit) is a fully assembled
and tested circuit board that uses the MAX9700B filter-
less 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 1.2W into an 8Ωload.
The EV kit accepts differential or single-ended input
signals. The EV kit provides an option to select between
different switching frequency modes of operation. The
MAX9700B EV kit also evaluates the MAX9700A/
MAX9700C/MAX9700D and the MAX9712.
Features
♦Filterless Operation Passes FCC Radiated
Emissions
♦Evaluates the MAX9700A/B/C/D or MAX9712 (with
IC Replacement)
♦2.5V to 5.5V Single-Supply Operation
♦Up to 94% Efficiency
♦Drives 1.2W into 8ΩSpeaker at 1% THD+N
♦Differential or Single-Ended Inputs
♦Selectable Switching Frequency
♦0.1µA Shutdown Current
♦Small 10-Pin TDFN Package
♦Also Available in 10-Pin µMAX and 12-Bump
UCSP™ Packages
♦Fully Assembled and Tested
Evaluates: MAX9700A/B/C/D/MAX9712
MAX9700B Evaluation Kit
________________________________________________________________ Maxim Integrated Products 1
19-3248; Rev 0; 4/04
Component List
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Ordering Information
*EP = Exposed paddle.
DESIGNATION
QTY
DESCRIPTION
A1 0 Not installed, MAX9700BEUB
(10-pin µMAX)
A2 0 Not installed, MAX9700BEBC-T
(12-bump UCSP)
C1, C2 2
0.1µF ±10%, 25V X7R ceramic
capacitors (0603)
TDK C1608X7R1E104K
C3 1
10µF ±20%, 6.3V X5R ceramic
capacitor (0805)
TDK C2012X5R0J106M
C4 0 Not installed, capacitor (0805)
C5, C6 2
1µF ±10%, 10V X5R ceramic
capacitors (0603)
TDK C1608X5R1A105K
C7, C8, C9,
C11–C14 0Not installed, capacitors (0603)
C10 1
100pF ±5%, 50V C0G ceramic
capacitor (0603)
TDK C1608C0G1H101J
DESIGNATION QTY DESCRIPTION
JU1 1 3-pin header
JU2 1 5-pin header
JU3 1 2-pin header
L1, L2 0
Not installed, inductors
recommended
TOKO D53LC series
L3, L4, L5 3
Ferrite beads 100Ω at 100MHz,
50mΩ DCR, 3A (0603)
TDK MPZ1608S101A
R1 1 49.9Ω ±1% resistor (0603)
R2, R3 0 Not installed, resistors (0603)
T1 0
Not installed, common-mode choke
50VDC, 1ADC 800Ω at 100MHz
recommended
TDK ACM4532-801-2P-X
U1 1 MAX9700BETB
(10-pin TDFN, 3mm x 3mm x 0.8mm))
None 3 Shunts (JU1, JU2, JU3)
None 1 MAX9700B PC board
PART TEMP RANGE IC PACKAGE
MAX9700BEVKIT 0°C to +70°C 10 TDFN-EP*
UCSP is a trademark of Maxim Integrated Products, Inc.
Evaluates: MAX9700A/B/C/D/MAX9712
MAX9700B Evaluation Kit
2_______________________________________________________________________________________
Quick Start
The MAX9700B EV kit is fully assembled and tested.
Follow the steps listed below to verify board operation.
Do not turn on the power supply until all connec-
tions are completed.
Recommended Equipment:
•2.5V to 5.5V, 1A power supply
•Audio source (i.e. CD player, cassette player)
•8Ωspeaker
Procedures:
1) Install a shunt across pins 1 and 2 of jumper JU1
(EV kit ON).
2) Install a shunt across pins 1 and 2 of jumper JU2
(internal oscillator set to spread-spectrum mode).
3) Verify that no shunt is across jumper JU3 (differen-
tial input mode).
4) Connect the 8Ωspeaker across the OUT+ and
OUT- test points.
5) Connect the positive terminal of the power supply to
the VDD pad and the power-supply ground terminal
to the GND pad.
6) Connect the audio source across the INPUT+ and
INPUT- pads.
7) Turn on the power supply.
8) Turn on the audio source.
Detailed Description
The MAX9700B EV kit features the MAX9700B filterless
class D amplifier IC, designed to drive a BTL mono
speaker in portable audio applications. The EV kit oper-
ates from a DC power supply that can provide 2.5V to
5.5V and 1A of current. The EV kit accepts a differential
or single-ended audio input. The audio input source is
amplified to drive 1.2W into an 8Ωspeaker.
The EV kit provides three sets of differential outputs.
The device outputs (OUT+/-) can be connected directly
to a speaker load without any filtering. However, a filter
can be added to ease evaluation. The filtered outputs
(FOUTPUT+/-) require installation of filtering compo-
nents L1, L2, C7, C8, C9, C13, C14, R2, and R3. When
an LCR filter is required, remove C11, C12, and T1,
short T1-1 to T1-4, and short T1-2 to T1-3. See Table 1
for the suggested filtering component values for an 8Ω
load and a 30kHz cutoff frequency.
The MAX9700B is designed to pass FCC Class-B RF
emissions without additional filtering when using 10cm of
cable to connect the speaker. In applications where more
margin and/or cable length are required, output capaci-
tors C11, C12 and common-mode choke T1 can be
added to reduce radiated emission. Connect the speaker
to output +/- test points. Table 2 lists the cable length
verses the required output components.
Component Suppliers
Note: Please indicate that you are using the MAX9700B when contacting these component suppliers.
SUPPLIER PHONE FAX WEBSITE
TDK 847-803-6100 847-390-4405 www.component.tdk.com
TOKO 847-297-0070 847-699-1194 www.tokoam.com
COMPONENT VALUE
L1, L2 15µH
C7, C8 0.033µF
C9 0.15µF
C13, C14 0.068µF
R2, R3 22Ω
Table 1. Suggested Filtering Components
for an 8ΩLoad and 30kHz Cut-Off
CABLE
LENGTH X
(CM)
OUTPUT
CAPACITOR
C11 AND C12
COMMON-
MODE
CHOKE T1
LCR FILTER
L1, L2, C7, C8,
C9, C13, C14,
R2, R3
X < 10 — — —
10 < X < 15
Required (100pF)
——
15 < X < 30
Required (100pF) Required
—
X > 30 — — Required*
Table 2. Cable Length vs. Suggested
Output Components
*When an LCR filter is required, remove C11, C12 and T1, short
T1-1 to T1-4, short T1-2 to T1-3.
Evaluates: MAX9700A/B/C/D/MAX9712
MAX9700B Evaluation Kit
_______________________________________________________________________________________ 3
SHUNT POSITION EV KIT FUNCTION
1-2 (SHDN = high) EV kit enabled
2-3 (SHDN = low) Shutdown mode
None. External
controller connected to
SHDN pad (TTL).
SHDN driven by external controller.
Shutdown is active low.
Table 3. JU1 Jumper Selection
SHUNT POSITION EV KIT INPUT MODE
None
(default) Differential Input Mode
Installed
(IN- pad connected to GND)
Single-Ended Input Mode
Table 5. JU3 Jumper Selection
SHUNT
MAX9700B SYNC
PIN
INTERNAL
OSCILLATOR
FREQUENCY
1-2
SYNC pin = high
Spread-Spectrum Mode.
Set at a switching
frequency fSW =
1.22MHz ±120kHz
1-3 SYNC pin = floating Set at fNOM = 1.45MHz
1-4
SYNC pin = external
TTL-compatible clock
input. External clock
input connected to
SYNC (TTL).
Synchronized to the
incoming TTL-compatible
clock frequency
1-5 SYNC = low Set at the nominal
Table 4. JU2 Jumper Selection
Switching Frequency Mode (Sync)
Jumper JU2 provides an option to select the switching
frequency of the MAX9700B IC. See Table 4 for the
various shunt positions.
Input Mode
Jumper JU3 provides an option to select between a
differential or single-ended input mode for the EV kit.
See Table 5 for shunt positions.
Evaluating the MAX9700A/MAX9700C/MAX9700D
and the MAX9712
The MAX9700B EV kit can evaluate the MAX9700A,
MAX9700C, MAX9700D, and the MAX9712. To evalu-
ate a different IC, replace U1 with the desired part.
Refer to the MAX9700 or the MAX9712 data sheets for
additional information.
Jumper Selection
Shutdown Mode
(SHDN)
Jumper JU1 controls the shutdown pin (SHDN) of the
MAX9700B IC. See Table 3 for shunt positions.
Evaluates: MAX9700A/B/C/D/MAX9712
MAX9700B Evaluation Kit
4_______________________________________________________________________________________
Figure 2. MAX9700B EV Kit Component Placement Guide—
Component Side Figure 3. MAX9700B EV Kit PC Board Layout—Component
Side
U1
MAX9700B
1VDD
GND
IN+
IN-
SHDN
SYNC
4
2
3
5
6
C1
0.1µF
C5
1.0µF
C6
1.0µF
C10
100pF
SHDN
INPUT+ L3
FERRITE
INPUT- L4
FERRITE
JU3
JU1
12
3
VDD
VDD
GND
L5
FERRITE
VDD
JU2
SYNC
1
24
3
5
FOUTPUT-
FOUTPUT+
R1
49.9Ω
1%
OUT+
OUT-
PGND
PVDD
823
14
9
7
10
C2
0.1µFC3
10µFC4
OPEN
C11
OPEN
C12
OPEN
OUT-
OUT+
C8
OPEN C9
OPEN
C13
OPEN
R2
OPEN
C7
OPEN
T1
OPEN
L1
OPEN
L2
OPEN
OUTPUT-
OUTPUT+
C14
OPEN
R3
OPEN
Figure 1. MAX9700B EV Kit Schematic
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 5
©2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Evaluates: MAX9700A/B/C/D/MAX9712
MAX9700B Evaluation Kit
Figure 4. MAX9700B EV Kit PC Board Layout—GND Layer 2 Figure 5. MAX9700B EV Kit PC Board Layout—GND Layer 3
Figure 6. MAX9700B EV Kit PC Board Layout—Solder Side Figure 7. MAX9700B EV Kit Component Placement Guide—
Solder Side