MAX9708 Datasheet, PDF (1/24 Pages) Maxim Integrated Products – 20W/40W, Filterless, Spread-Spectrum, Mono/Stereo, Class D Amplifier

19-3678; Rev 0; 7/05
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20W/40W, Filterless, Spread-Spectrum,
Mono/Stereo, Class D Amplifier
General Description
The MAX9708 mono/stereo, Class D audio power ampli-
fier delivers up to 2 x 21W into an 8Ω stereo mode and
1 x 42W into a 4Ω load in mono mode while offering up
to 87% efficiency. The MAX9708 provides Class AB
amplifier performance with the benefits of Class D effi-
ciency, eliminating the need for a bulky heatsink and
conserving power. The MAX9708 operates from a single
+10V to +18V supply, driving the load in a BTL configu-
ration.
The MAX9708 offers two modulation schemes: a fixed-
frequency modulation (FFM) mode, and a spread-spec-
trum modulation (SSM) mode that reduces
EMI-radiated emissions. The MAX9708 can be synchro-
nized to an external clock from 600kHz to 1.2MHz. A
synchronized output allows multiple units to be cascad-
ed in the system.
Features include fully differential inputs, comprehensive
click-and-pop suppression, and four selectable-gain set-
tings (22dB, 25dB, 29.5dB, and 36dB). A pin-program-
mable thermal flag provides seven different thermal
warning thresholds. Short-circuit and thermal-overload
protection prevent the device from being damaged
during a fault condition.
The MAX9708 is available in 56-pin TQFN (8mm x 8mm
x 0.8mm) and 64-pin TQFP (10mm x 10mm x 1.4mm)
packages, and is specified over the extended
-40°C to +85°C temperature range.
Applications
LCD TVs
Automotive
PDP TVs
PC/HiFi Audio Solutions
Pin Configurations appear at end of data sheet.
Features
♦ 2 x 21W Output Power in Stereo Mode
(8Ω, THD = 10%)
♦ 1 x 42W Output Power in Mono Mode
(4Ω, THD = 10%)
♦ High Efficiency: Up to 87%
♦ Filterless Class D Amplifier
♦ Unique Patented Spread-Spectrum Mode
♦ Programmable Gain (+22dB, +25dB, +29.5dB,
+36dB)
♦ High PSRR (90dB at 1kHz)
♦ Differential Inputs Suppress Common-Mode
Noise
♦ Shutdown and Mute Control
♦ Integrated Click-and-Pop Suppression
♦ Low 0.1% THD+N
♦ Current Limit and Thermal Protection
♦ Programmable Thermal Flag
♦ SYNC Input/Output
♦ Available in Thermally Efficient, Space-Saving
Packages: 56-Pin TQFN and 64-Pin TQFP
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX9708ETN -40°C to +85°C 56 TQFN-EP**
MAX9708ECB* -40°C to +85°C 64 TQFP-EP**
*Future product—Contact factory for availability.
**EP = Exposed paddle.
PKG
CODE
T5688-3
C64E-6
Simplified Block Diagram
FS1, FS2
SYNC
RIGHT
CHANNEL
LEFT
CHANNEL
MONO
2
G1, G2
TH0, TH1,
TH2
2
MAX9708
SYNCOUT
GAIN
CONTROL
CLASS D
MODULATOR
OUTPUT
PROTECTION
3
TEMP
STEREO MODE
2
FS1, FS2
SYNC
MAX9708
SYNCOUT
AUDIO
INPUT
VDIGITAL
MONO
2
G1, G2
TH0, TH1,
TH2
GAIN
CONTROL
CLASS D
MODULATOR
OUTPUT
PROTECTION
3
TEMP
MONO MODE
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