19-0746; Rev 4; 8/08
2 x 1.5W, Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
5/MAX976
General Description
Features
♦ Unique Spread-Spectrum Modulation and Active
The MAX9775/MAX9776 combine a high-efficiency
Class D, stereo/mono audio power amplifier with a
mono DirectDrive® receiver amplifier and a stereo
DirectDrive headphone amplifier.
Emissions Limiting Significantly Reduces EMI
♦ 3D Stereo Enhancement (MAX9775 Only)
♦ Up to 3 Stereo Inputs
Maxim’s 3rd-generation, ultra-low-EMI, Class D audio
power amplifiers provide Class AB performance with
Class D efficiency. The MAX9775/MAX9776 deliver
1.5W per channel into a 4Ω load from a 5V supply and
offer efficiencies up to 79%. Active emissions limiting
circuitry and spread-spectrum modulation greatly
reduce EMI, eliminating the need for output filtering
found in traditional Class D devices.
♦ 1.5W Stereo Speaker Output (4Ω, V
= 5V)
DD
♦ 50mW Mono Receiver/Stereo Headphone Outputs
(32Ω, V = 3.3V)
DD
♦ High PSRR (68dB at 217Hz)
♦ 79% Efficiency (V
= 3.3V, R = 8Ω, P
=
DD
L
OUT
470mW)
♦ I2C Control—Input Configuration, Volume Control,
Output Mode
The MAX9775/MAX9776 utilize a fully differential archi-
tecture, a full-bridged output, and comprehensive click-
and-pop suppression. A 3D stereo enhancement
function allows the MAX9775 to widen the stereo sound
field immersing the listener in a cleaner, richer sound
experience than typically found in portable applications.
The devices utilize a flexible, user-defined mixer archi-
tecture that includes an input mixer, volume control, and
output mixer. All control is done through I2C.
♦ Click-and-Pop Suppression
♦ Low Total Harmonic Distortion (0.03% at 1kHz)
♦ Current-Limit and Thermal Protection
♦ Available in Space-Saving, 36-Bump WLP (3mm x
3mm) and 32-Pin TQFN (5mm x 5mm) Packages
Ordering Information
CLASS D
AMPLIFIER
PART
PIN-PACKAGE
The mono receiver amplifier and stereo headphone
amplifier use Maxim’s DirectDrive architecture that pro-
duces a ground-referenced output from a single supply,
eliminating the need for large DC-blocking capacitors,
saving cost, space, and component height.
MAX9775EBX+T
MAX9776ETJ+
MAX9776EBX+T
36 WLP*
Stereo
Mono
Mono
32 TQFN-EP**
36 WLP*
The MAX9775 is available in a 36-bump WLP (3mm x
3mm) package. The MAX9776 is available in a 32-pin
TQFN (5mm x 5mm) or a 36-bump WLP (3mm x 3mm)
package. Both devices are specified over the extended
-40°C to +85°C temperature range.
Applications
Cell Phones
Note: All devices are specified over the -40°C to +85°C oper-
ating temperature range.
+Denotes a lead-free/RoHS-compliant package.
*Four center bumps depopulated.
**EP = Exposed pad.
Pin Configurations appear at end of data sheet.
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
Portable Multimedia Players
Handheld Gaming Consoles
Simplified Block Diagrams
SINGLE SUPPLY 2.7V TO 5.5V
SINGLE SUPPLY 2.7V TO 5.5V
3D
SOUND
CONTROL
GAIN
CONTROL
GAIN
CONTROL
MIXER/
MUX
MIXER/
MUX
2
2
I C
I C
INTERFACE
INTERFACE
MAX9775
MAX9776
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.