MAXIM MAX9875 Low RF Susceptibility, Mono Audio Subsystem with DirectDrive Headphone Amplifier User's Manual
Summary
The MAX9875 is a high-performance, low RF susceptibility audio power amplifier designed for portable multimedia players and mobile devices. It delivers crystal-clear sound with 725mW speaker output and uses DirectDrive technology to minimize electrical noise (EMI) from modern sources. This manual provides detailed technical specifications, typical application circuits, and integration guidance for designers requiring a highly efficient, single-supply audio solution that maintains pristine audio quality while saving vital space on the PCB.
Page 1 Text Content
19-4536; Rev 0; 3/09
EVALUATION KIT AVAILABLE
Low RF Susceptibility, Mono Audio
Subsystem with Direct Drive Headphone Amplifier
General Description Features
The MAX9875 combines a high-efficiency Class D Low Emissions, Filterless Class D Amplifier audio power amplifier with a stereo Class AB capacitor- Achieves Better than 10d B Margin Under EN55022 less Direct Drive® headphone amplifier. Maxim’s 3rd Class B Limits generation, filterless Class D amplifier with active emis- Low RF Susceptibility Design Rejects TDMA sions limiting technology provides Class AB perfor- Noise from GSM Radios mance with Class D efficiency. Input Mixer with User-Defined Input Mode 725m W Speaker Output (RSPK = 8Ω, PVDD = 3.7V)
The MAX9875 delivers up to 725m W from a 3.7V supply
53m W Headphone Output (RHP = 16Ω, VDD = 3.7V)
into an 8Ω load with 87% efficiency to extend battery life.
Low 0.05% THD+N at 1k Hz (Class D Power
The filterless modulation scheme combined with active
Amplifier)
emissions limiting circuitry and spread-spectrum modu-
Low 0.016% THD+N at 1k Hz (Headphone
lation greatly reduces EMI while eliminating the need for
Amplifier)
output filtering used in traditional Class D devices.
87% Efficiency (RSPK = 8Ω, POUT = 750m W)
The stereo Class AB headphone amplifier in the
High Speaker Amplifier PSRR (72d B at 217Hz)
MAX9875 uses Maxim’s Direct Drive architecture, that
High Headphone Amplifier PSRR (84d B at 217Hz)
produces a ground-referenced output from a single sup-
I2C Control
ply, eliminating the need for large DC-blocking capaci-
Hardware and Software Shutdown Mode
tors, saving cost, space, and component height.
Click-and-Pop Suppression
The device utilizes a user-defined input architecture, Current-Limit and Thermal Protection three preamplifier gain settings, an input mixer, volume
Available in a Space-Saving, 2.5mm x 2.0mm WLP
control, comprehensive click-and-pop suppression, and Package I2C control. The MAX9875 is available in a thermally efficient,
space-saving 20-bump WLP package. Ordering Information
Applications PART TEMP RANGE PIN - PA C K A G E
Cell Phones MAX9875ERP+TG45 -40°C to +85°C 20 WLP (5x4) Portable Multimedia Players +Denotes a lead(Pb)-free/Ro HS-compliant package. T = Tape and reel. G45 indicates protective die coating.Direct Drive is a registered trademark of Maxim Integrated
Products, Inc.
Simplified Block Diagram Pin Configuration SINGLE SUPPLY
TOP VIEW
2.7V TO 5.25V
(BUMP SIDE DOWN)
VOLUME
PREAMPLIFIER
CONTROL
HPL VSS C1NHPR C1P
MIXER/MUX
BIAS SDA N.C.VDD OUT+
VOLUME
I2C CONTROL INTERFACE
INB1 SCL PGNDINB2 PVDD
INA1 GND N.C.INA2 OUT-
MAX9875
Maxim Integrated Products
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.
Page Summary Contents For MAXIM MAX9875 Low RF Susceptibility, Mono Audio Subsystem with DirectDrive Headphone Amplifier User's Manual
Manual Details
| Brand | Audio |
|---|---|
| Pages | 30 |
| File Size | 490.16 KB |
| Published | May 15, 2026 |
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Frequently Asked Questions
What kind of amplifier technology does the MAX9875 use for high efficiency?
It uses a high-efficiency Class D filterless modulation scheme that combines with active emissions limiting circuitry.
How much power can the speaker output achieve under typical conditions?
The device delivers up to 725mW (R = 8Ω, PVDD = 3.7V) from the speaker output.
Can this amplifier maintain low audio distortion and electromagnetic interference?
Yes, it achieves low THD+N of 0.016% at 1kHz for headphone output due to filterless modulation.
What is the operating temperature range for the MAX9875 chip?
The operating temperature range is -40°C to +85°C.
Is the device suitable for small, space-constrained projects?
Yes, it comes in a space-saving 2.5mm x 2.0mm WLP package.