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.
General Description
The MAX9770 combines a mono, filterless, Class D
speaker amplifier and stereo DirectDrive headphone
amplifier in a single device. The MAX9770 operates
from a single 2.5V to 5.5V supply and includes features
that reduce external component count, system cost,
board space, and offer improved audio reproduction.
The speaker amplifier makes use of Maxim’s Class D
architecture, providing Class AB performance with Class
D efficiency, conserving board space, and extending
battery life. The speaker amplifier delivers 1.2W into an
8Ω load while offering efficiencies above 85%. A spread-
spectrum modulation scheme reduces radiated emis-
sions caused by the modulation frequency. Furthermore,
the MAX9770 oscillator can be synchronized to an exter-
nal clock through the SYNC input, avoiding possible
problem frequencies inside a system. The speaker
amplifier features THD+N as low as 0.025%, high 70dB
PSRR, and SNR in excess of 90dB.
The headphone amplifiers feature Maxim’s DirectDrive
architecture that produces a ground-referenced output
from a single supply, eliminating the need for large DC-
blocking capacitors. The headphone amplifiers deliver up
to 80mW into a 16Ω load, feature low 0.015% THD+N,
high 85dB PSRR, and
±8kV ESD-protected outputs. A
headphone sense input detects the presence of a head-
phone, and automatically configures the amplifiers for
either speaker or headphone mode.
The MAX9770 includes internally set, logic-selectable
gain, and a comprehensive input multiplexer/mixer, allow-
ing multiple audio sources to be selected and for true
mono reproduction of a stereo source in speaker mode.
Industry-leading click-and-pop suppression eliminates
audible transients during power and shutdown cycles. A
low-power shutdown mode decreases supply current
consumption to 0.1A, further extending battery life.
The MAX9770 is offered in space-saving, thermally effi-
cient 28-pin TQFN (5mm x 5mm x 0.8mm) and 28-pin
TSSOP packages. The MAX9770 features thermal-over-
load and output short-circuit protection, and is speci-
fied over the extended -40°C to +85°C temperature
range.
Applications
Cellular Phones
Compact Notebooks
PDAs
Features
1.2W Filterless Class D Amplifiers Pass FCC
Class B Radiated EMI Standards with 100mm
of Cable
Spread-Spectrum Mode Offers 5dB EMI
Improvement over Conventional Methods
80mW DirectDrive Headphone Amplifier
Eliminates Bulky DC-Blocking Capacitors
High 85dB PSRR at 217Hz
85% Efficiency
Low 0.015% THD+N
Industry-Leading Click-and-Pop Suppression
Integrated 3-Way Input Mixer/Multiplexer
(MAX9770)
Logic-Adjustable Gain
Short-Circuit and Thermal Protection
Available in Space-Saving, Thermally Efficient
Packages
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiers
________________________________________________________________
Maxim Integrated Products
1
SPKR
(MONO)
MAX9770
CLASS
D
VDD
DirectDrive
STEREO
HEADPHONE
IN1L
IN2L
IN1R
IN2R
MONO
GAIN SEL
INPUT SEL
MUTE
SHDN
HPS
PART
PIN-PACKAGE
SELECTABLE INPUTS
MAX9770ETI+
28 TQFN-EP*
2 stereo, 1 mono
MAX9770EUI
28 TSSOP
2 stereo, 1 mono
Ordering Information
Simplified Block Diagram
19-3134; Rev 2; 4/08
Note: All devices specified over the -40°C to +85°C operating
temperature range.
*
EP = Exposed pad.
+Denotes a lead-free package.
EVALUATION KIT
AVAILABLE
Pin Configuration appears at end of data sheet.