General Description

The MAX9708 mono/stereo, Class D audio power ampli-

fier delivers up to 2 x 21W into an 8

Ω stereo mode and

1 x 42W into a 4

Ω 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

PDP TVs

Automotive

PC/HiFi Audio Solutions

Features

♦ 2 x 21W Output Power in Stereo Mode

(8

Ω, THD = 10%)

♦ 1 x 42W Output Power in Mono Mode

(4

Ω, 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

20W/40W, Filterless, Spread-Spectrum,

Mono/Stereo, Class D Amplifier

________________________________________________________________ Maxim Integrated Products

1

CLASS D

MODULATOR

SYNCOUT

TEMP

OUTPUT

PROTECTION

GAIN

CONTROL

FS1, FS2

MAX9708

STEREO MODE

G1, G2

2

SYNC

RIGHT

CHANNEL

LEFT

CHANNEL

MONO

2

TH0, TH1,

TH2

3

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX9708ETN

-40°C to +85°C

56 TQFN-EP**

T5688-3

MAX9708ECB*

-40°C to +85°C

64 TQFP-EP**

C64E-6

Simplified Block Diagram

Ordering Information

19-3678; Rev 0; 7/05

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.

*Future product—Contact factory for availability.

**EP = Exposed paddle.

Pin Configurations appear at end of data sheet.

EVALUATION

KIT

AVAILABLE

CLASS D

MODULATOR

SYNCOUT

TEMP

OUTPUT

PROTECTION

GAIN

CONTROL

FS1, FS2

MAX9708

MONO MODE

G1, G2

2

SYNC

AUDIO

INPUT

MONO

2

TH0, TH1,

TH2

3