19-3030; Rev 2; 10/08
1.2W, Low-EMI, Filterless,
Class D Audio Amplifier
MAX970
General Description
Features
♦ Filterless Amplifier Passes FCC Radiated
The MAX9700 mono class D audio power amplifier pro-
vides class AB amplifier performance with class D effi-
ciency, conserving board space and extending battery
life. Using a class D architecture, the MAX9700 delivers
1.2W into an 8Ω load while offering efficiencies above
90%. A patented, low-EMI modulation scheme renders
the traditional class D output filter unnecessary.
Emissions Standards with 100mm of Cable
♦ Unique Spread-Spectrum Mode Offers 5dB
Emissions Improvement Over Conventional
Methods
♦ Optional External SYNC Input
♦ Simple Master-Slave Setup for Stereo Operation
♦ 94% Efficiency
The MAX9700 offers two modulation schemes: a fixed-
frequency (FFM) mode, and a spread-spectrum (SSM)
mode that reduces EMI-radiated emissions due to the
modulation frequency. Furthermore, the MAX9700 oscil-
lator can be synchronized to an external clock through
the SYNC input, allowing the switching frequency to be
user defined. The SYNC input also allows multiple
MAX9700s to be cascaded and frequency locked, mini-
mizing interference due to clock intermodulation. The
device utilizes a fully differential architecture, a full-
bridged output, and comprehensive click-and-pop sup-
pression. The gain of the MAX9700 is set internally
(MAX9700A: 6dB, MAX9700B: 12dB, MAX9700C:
15.6dB, MAX9700D: 20dB), further reducing external
component count.
♦ 1.2W into 8Ω
♦ Low 0.01% THD+N
♦ High PSRR (72dB at 217Hz)
♦ Integrated Click-and-Pop Suppression
♦ Low Quiescent Current (4mA)
♦ Low-Power Shutdown Mode (0.1µA)
♦ Short-Circuit and Thermal-Overload Protection
♦ Available in Thermally Efficient, Space-Saving
Packages
10-Pin TDFN (3mm x 3mm x 0.8mm)
10-Pin µMAX
12-Bump UCSP (1.5mm x 2mm x 0.6mm)
Ordering Information
The MAX9700 features high 72dB PSRR, a low 0.01%
THD+N, and SNR in excess of 90dB. Short-circuit and
thermal-overload protection prevent the device from
damage during a fault condition. The MAX9700 is avail-
able in 10-pin TDFN (3mm ✕ 3mm ✕ 0.8mm), 10-pin
µMAX®, and 12-bump UCSP™ (1.5mm ✕ 2mm ✕ 0.6mm)
packages. The MAX9700 is specified over the extended
-40°C to +85°C temperature range.
PIN-
PACKAGE
TOP
MARK
PART
TEMP RANGE
MAX9700AETB
MAX9700AEUB
MAX9700AEBC-T
MAX9700BETB
-40oC to +85oC 10 TDFN-EP*
-40oC to +85oC 10 µMAX
-40oC to +85oC 12 UCSP
-40oC to +85oC 10 TDFN-EP*
-40oC to +85oC 10 µMAX
-40oC to +85oC 12 UCSP
ACM
—
—
ACI
—
Applications
MP3 Players
MAX9700BEUB
MAX9700BEBC-T
*EP = Exposed pad.
Cellular Phones
PDAs
—
Portable Audio
Ordering Information continued and Selector Guide appears
at end of data sheet.
Block Diagram
V
DD
Pin Configurations
TOP VIEW
DIFFERENTIAL
AUDIO INPUT
MODULATOR
AND H-BRIDGE
V
1
2
3
4
5
10 PV
DD
DD
IN+
IN-
9
8
7
6
OUT-
OUT+
PGND
SYNC
MAX9700
SYNC
INPUT
OSCILLATOR
GND
SHDN
MAX9700
TDFN/μMAX
UCSP is a trademark of Maxim Integrated Products, Inc.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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.