19-4651; Rev 0; 5/09
Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
MX987AERP
General Description
Features
o Low Emissions, Filterless Class D Amplifier
The MAX9877A combines a high-efficiency Class D
audio power amplifier with a stereo Class AB capacitor-
less DirectDrive® headphone amplifier. Maxim’s 3rd
generation, filterless Class D amplifier with active emis-
sions limiting* technology provides Class AB perfor-
mance with Class D efficiency.
Achieves Better than 10dB Margin Under EN55022
Class B Limits
o Low RF Susceptibility Design Rejects TDMA
Noise from GSM Radios
o Input Mixer with User-Defined Input Mode
o 725mW Speaker Output (R
o 53mW Headphone Output (R = 16Ω, V
= 8Ω, PV
HP
= 3.7V)
= 3.7V)
DD
SPK
DD
The MAX9877A delivers up to 725mW from a 3.7V supply
into an 8Ω load with 87% efficiency to extend battery life.
The filterless modulation scheme combined with active
emissions limiting circuitry and spread-spectrum modula-
tion** greatly reduces EMI while eliminating the need for
output filtering used in traditional Class D devices.
o Low 0.05% THD+N at 1kHz (Class D Power
Amplifier)
o Low 0.016% THD+N at 1kHz (Headphone
Amplifier)
o 87% Efficiency (R
= 8Ω, P
= 750mW)
SPK
OUT
The stereo Class AB headphone amplifier in the
MAX9877A uses Maxim’s patented DirectDrive architec-
ture, that produces a ground-referenced output from a
single supply, eliminating the need for large DC-blocking
capacitors, saving cost, space, and component height.
o 1.6ΩΩ Analog Switch for Speaker Amplifier Bypass
o High Speaker Amplifier PSRR (72dB at 217Hz)
o High Headphone Amplifier PSRR (84dB at 217Hz)
o I2C Control
o Hardware and Software Shutdown Mode
o Click-and-Pop Suppression
o Current-Limit and Thermal Protection
o Available in a Space-Saving, 2.5mm x 2.0mm
MaxFilm Package
The device utilizes a user-defined input architecture,
three preamplifier gain settings, an input mixer, volume
control, comprehensive click-and-pop suppression, and
I2C control. A bypass mode feature disables the integrat-
ed Class D amplifier and utilizes an internal DPST switch
to allow an external amplifier to drive the speaker that is
connected at the outputs of the MAX9877A.
Ordering Information
The MAX9877A is available in a thermally efficient,
space-saving 20-bump MaxFilm package.
PART
TEMP RANGE
PIN-PACKAGE
MAX9877AERP+T
-40°C to +85°C
20 MaxFilm (5x4)
Applications
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Cell Phones
Portable Multimedia Players
*U.S. Patent #7,190,225.
**U.S. Patent #6,847,257.
Pin Configuration
Simplified Block Diagram
SINGLE SUPPLY
2.7V TO 5.25V
TOP VIEW
(BUMP SIDE DOWN)
2
3
4
1
5
VOLUME
CONTROL
PREAMPLIFIER
A
HPR
HPL
V
C1N
C1P
SS
SDA
SCL
MIXER/MUX
B
V
BIAS
RXIN+
OUT+
DD
VOLUME
CONTROL
2
I C
C
D
INTERFACE
INB2
INA2
INB1
INA1
PGND
RXIN-
PV
DD
BYPASS
GND
OUT-
MAX9877A
MaxFilm
________________________________________________________________ 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.