19-4536; Rev 0; 3/09
Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
MAX9875
General Description
Features
♦ Low Emissions, Filterless Class D Amplifier
The MAX9875 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
♦ Low RF Susceptibility Design Rejects TDMA
Noise from GSM Radios
♦ Input Mixer with User-Defined Input Mode
♦ 725mW Speaker Output (R
= 8Ω, PVDD = 3.7V)
SPK
The MAX9875 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 modu-
lation greatly reduces EMI while eliminating the need for
output filtering used in traditional Class D devices.
♦ 53mW Headphone Output (R = 16Ω, V
= 3.7V)
DD
HP
♦ Low 0.05% THD+N at 1kHz (Class D Power
Amplifier)
♦ Low 0.016% THD+N at 1kHz (Headphone
Amplifier)
♦ 87% Efficiency (R
= 8Ω, P
= 750mW)
SPK
OUT
The stereo Class AB headphone amplifier in the
MAX9875 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.
♦ High Speaker Amplifier PSRR (72dB at 217Hz)
♦ High Headphone Amplifier PSRR (84dB at 217Hz)
♦ I2C Control
♦ Hardware and Software Shutdown Mode
♦ Click-and-Pop Suppression
♦ Current-Limit and Thermal Protection
♦ Available in a Space-Saving, 2.5mm x 2.0mm WLP
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.
The MAX9875 is available in a thermally efficient,
space-saving 20-bump WLP package.
Ordering Information
Applications
PART
TEMP RANGE
PIN-PACKAGE
MAX9875ERP+TG45
-40°C to +85°C
20 WLP (5x4)
Cell Phones
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
G45 indicates protective die coating.
Portable Multimedia Players
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
Simplified Block Diagram
Pin Configuration
SINGLE SUPPLY
2.7V TO 5.25V
TOP VIEW
(BUMP SIDE DOWN)
2
3
4
1
5
VOLUME
A
PREAMPLIFIER
CONTROL
HPR
HPL
V
C1N
N.C.
C1P
SS
SDA
SCL
MIXER/MUX
B
V
DD
BIAS
OUT+
VOLUME
CONTROL
2
C
D
I C
INTERFACE
INB2
INA2
INB1
INA1
PGND
N.C.
PVDD
OUT-
GND
MAX9875
WLP
________________________________________________________________ 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.