The MAX9773 3rd-generation, ultra-low EMI, stereo,
Class D audio power amplifier provides Class AB performance
with Class D efficiency. The MAX9773 delivers
1.8W per channel into a 4Ω load, and offers
efficiencies above 90%. Active emissions limiting (AEL)
circuitry greatly reduces EMI by actively controlling the
output FET gate transitions under all possible transient
conditions. AEL controls high-frequency emissions
resulting from conventional Class D free-wheeling
behavior in the presence of an inductive load. Zerodead-
time (ZDT) technology maintains state-of-the-art
efficiency and THD+N performance by allowing the output
FETs to switch simultaneously without cross conduction.
A patented spread-spectrum modulation
scheme eliminates the need for output filtering found in
traditional Class D devices. These design concepts
reduce component count and extend battery life.
The MAX9773 offers two modulation schemes: a fixedfrequency
(FFM) mode, and a spread-spectrum (SSM)
mode that reduces EMI-radiated emissions. The
MAX9773 oscillator can be synchronized to an external
clock through the SYNC input, allowing synchronization
of multiple Maxim Class D amplifiers. The sync
output (SYNC_OUT) can be used for a master-slave
application where more channels are required. The
MAX9773 features a fully differential architecture, a full
bridge-tied load (BTL) output, and comprehensive
click-and-pop suppression. The device features internally
set gains of 12dB, 15.6dB, 20dB, and 26dB
selected through two gain-select inputs, further reducing
external component count.
The MAX9773 features high 80dB PSRR, less than
0.1% THD+N, and SNR in excess of 88dB. Short-circuit
and thermal-overload protection prevent the device
from being damaged during a fault condition. The
MAX9773 is available in 24-pin thin QFN-EP (4mm x
4mm x 0.8mm), and 20-bump UCSP? (2mm x 2.5mm x
0.6mm) packages. The MAX9773 is specified over the
extended -40°C to +85°C temperature range.
Applications
Cellular/Multimedia Phones
Notebooks
Handheld Gaming Consoles
MP3 Players