General Description
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 low-EMI modulation scheme renders the tradi-
tional class D output filter unnecessary.
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.
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.
Applications
Features
♦ Filterless Amplifier Passes FCC Radiated
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
♦ 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)
MAX9700
1.2W, Low-EMI, Filterless,
Class D Audio Amplifier
________________________________________________________________
Maxim Integrated Products
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