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MAXIM MAX9775 MAX9776 2x1.5W, Stereo Class-D Audio Subsystem with DirectDrive Headphone Amplifier

Summary

High-efficiency Class D audio subsystems designed for next-generation portable electronics, including cell phones and multimedia players. This device offers powerful 1.5W stereo output, dedicated headphone amplification, and revolutionary DirectDrive technology featuring ultra-low EMI and high efficiency up to 79%. The comprehensive manual provides system integrators with detailed specifications, I²C control guidance, packaging options, and application circuit schematics needed for reliable audio design in space-constrained environments.

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Page 1 Text Content

19-0746; Rev 4; 8/08

2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier General Description Features

The MAX9775/MAX9776 combine a high-efficiency Unique Spread-Spectrum Modulation and Active Class D, stereo/mono audio power amplifier with a Emissions Limiting Significantly Reduces EMI

mono Direct Drive® receiver amplifier and a stereo 3D Stereo Enhancement (MAX9775 Only) Direct Drive headphone amplifier.

Up to 3 Stereo Inputs

Maxim’s 3rd-generation, ultra-low-EMI, Class D audio

1.5W Stereo Speaker Output (4Ω, VDD = 5V)

power amplifiers provide Class AB performance with

50m W Mono Receiver/Stereo Headphone Outputs

Class D efficiency. The MAX9775/MAX9776 deliver

(32Ω, VDD = 3.3V)

1.5W per channel into a 4Ω load from a 5V supply and

High PSRR (68d B at 217Hz)

offer efficiencies up to 79%. Active emissions limiting

circuitry and spread-spectrum modulation greatly 79% Efficiency (VDD = 3.3V, RL = 8Ω, POUT

reduce EMI, eliminating the need for output filtering 470m W)

found in traditional Class D devices. I2C Control—Input Configuration, Volume Control,

Output Mode

The MAX9775/MAX9776 utilize a fully differential archi-

tecture, a full-bridged output, and comprehensive click- Click-and-Pop Suppression

and-pop suppression. A 3D stereo enhancement

Low Total Harmonic Distortion (0.03% at 1k Hz)

function allows the MAX9775 to widen the stereo sound

Current-Limit and Thermal Protection

field immersing the listener in a cleaner, richer sound

Available in Space-Saving, 36-Bump WLP (3mm x

experience than typically found in portable applications.

3mm) and 32-Pin TQFN (5mm x 5mm) Packages

The devices utilize a flexible, user-defined mixer archi- tecture that includes an input mixer, volume control, and Ordering Information output mixer. All control is done through I2C.

CLASS D

The mono receiver amplifier and stereo headphone PART PIN-PACKAGE

AMPLIFIER

amplifier use Maxim’s Direct Drive architecture that pro-

duces a ground-referenced output from a single supply, MAX9775EBX+T 36 WLP* Stereo

eliminating the need for large DC-blocking capacitors, MAX9776ETJ+ 32 TQFN-EP** Mono saving cost, space, and component height.

MAX9776EBX+T 36 WLP* Mono

The MAX9775 is available in a 36-bump WLP (3mm x Note: All devices are specified over the -40°C to +85°C oper-

3mm) package. The MAX9776 is available in a 32-pin ating temperature range. TQFN (5mm x 5mm) or a 36-bump WLP (3mm x 3mm) +Denotes a lead-free/Ro HS-compliant package. package. Both devices are specified over the extended *Four center bumps depopulated. -40°C to +85°C temperature range. **EP = Exposed pad. Pin Configurations appear at end of data sheet.

Applications

Direct Drive is a registered trademark of Maxim Integrated

Cell Phones

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

GAIN SOUND GAIN CONTROL CONTROL CONTROL

MIXER/ MIXER/ MUX MUX

I2C I2C INTERFACE INTERFACE

MAX9775 MAX9776

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 MAX9775 MAX9776 2x1.5W, Stereo Class-D Audio Subsystem with DirectDrive Headphone Amplifier

Page 1 19-0746; Rev 4; 8/08 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier General Description Features The MAX9775/MAX9776 combine a high-efficiency Unique Spread-Spectrum Mo...
Page 2 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier ABSOLUTE MAXIMUM RATINGS VDD to GND..............................................................................6V Durat...
Page 3 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier ELECTRICAL CHARACTERISTICS (continued) (VDD = PVDD = CPVDD = 3.3V, VGND = VPGND = VCPGND = 0V, SHDN = VDD, I2C settings (...
Page 4 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier ELECTRICAL CHARACTERISTICS (continued) (VDD = PVDD = CPVDD = 3.3V, VGND = VPGND = VCPGND = 0V, SHDN = VDD, I2C settings (...
Page 5 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier ELECTRICAL CHARACTERISTICS (continued) (VDD = PVDD = CPVDD = 3.3V, VGND = VPGND = VCPGND = 0V, SHDN = VDD, I2C settings (...
Page 6 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier ELECTRICAL CHARACTERISTICS (continued) (VDD = PVDD = CPVDD = 3.3V, VGND = VPGND = VCPGND = 0V, SHDN = VDD, I2C settings (...
Page 7 /M TH D+ TH D+ 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (VDD = PVDD = CPVDD = 3.3V, GND = PGND = CPGND = 0V, SHDN = VDD, I2C def...
Page 8 TH D+ TH D+ 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (continued) (VDD = PVDD = CPVDD = 3.3V, GND = PGND = CPGND = 0V, SHDN = VDD...
Page 9 OU TP UT OW ER (W OU TP UT OW ER (m 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (continued) (VDD = PVDD = CPVDD = 3.3V, GND = PGND ...
Page 10 OU TP UT AG NI TU DE (d BV CR OS ST AL (d B) 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (continued) (VDD = PVDD = CPVDD = 3.3V, GN...
Page 11 TH D+ SU PP LY UR RE NT (m A) 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (continued) (VDD = PVDD = CPVDD = 3.3V, GND = PGND = CPGN...
Page 12 /M TH D+ PO ER IS SI PA TI ON (m 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (continued) (VDD = PVDD = CPVDD = 3.3V, GND = PGND = C...
Page 13 /M PO ER -S UP PL RE JE CT IO RA TI (d B) OU TP UT OW ER (m 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (continued) (VDD = PVDD = C...
Page 14 CR OS ST AL (d B) 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Operating Characteristics (continued) (VDD = PVDD = CPVDD = 3.3V, GND = PGND = CPGND = 0V, SHDN...
Page 15 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Pin Description—MAX9775 PIN NAME FUNCTION F1 PVDD Class D Power Supply E1 OUTL- Negative Left-Speaker Output D2 SCL Seria...
Page 16 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Pin Description—MAX9776 NAME FUNCTION TQFN UCSP F1 PVDD Class D Power Supply E1 OUT- Negative Left-Speaker Output D2 SCL ...
Page 17 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Application Circuits VDD VDD CPVSS VSS VDD PVDD 15 (A5) 17 (B5) 21 (D6) 1 (F1) C1 CPGND 12 (A3) 1μF CHARGE PUMP D...
Page 18 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Typical Application Circuits (continued) VDD VDD CPVSS VSS VDD PVDD 15 (A5) 17 (B5) 21 (D6) 1 (F1) C1 CPGND 12 (A3) 1μF C...
Page 19 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Detailed Description Direct Drive allows the headphone and mono receiver amplifiers to output ground-referenced signals f...
Page 20 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Operating Modes cycle-to-cycle variation of the switching period does not degrade audio reproduction or efficiency (see t...
Page 21 AM PL IT UD (d Bμ V/ 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier EN55022B LIMIT FREQUENCY (MHz) Figure 3. EMI with 76mm of Speaker Cable
Page 22 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Filterless Modulation/Common-Mode Idle The MAX9775/MAX9776 use Maxim’s unique modula- tion scheme that eliminates the LC ...
Page 23 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier VOUT VDD / 2 LISTENER CONVENTIONAL DRIVER-BIASING SCHEME Figure 6. MAX9775 3D Stereo Enhancement With Maxim’s 3D stereo e...
Page 24 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier if the right and left volume controls are set for a maxi- in the Input Mixer to create the internal signals L, R, mum gai...
Page 25 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Click-and-Pop Suppression I2C Interface In conventional single-supply headphone amplifiers, the The MAX9775/MAX9776 featu...
Page 26 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Bit Transfer the seven most significant bits (MSBs) followed by the One data bit is transferred during each SCL cycle. Th...
Page 27 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier The MAX9775/MAX9776 only accept write data, but COMMAND BYTE IS STORED ON they acknowledge the receipt of the address byt...
Page 28 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Input Mode Control Table 4. Input Mode Control Register REGISTER B7 B6 B5 B4 B3 B2 B1 B0 Input Mode Control INA+20d B INM...
Page 29 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Mono/Left/Right Volume Control Table 6. Mono/Left/Right Volume Control Registers REGISTER B7 B6 B5 B4 B3 B2 B1 B0 Mono Vo...
Page 30 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Output Mode Control Table 8. Output Mode Control Register REGISTER B7 B6 B5 B4 B3 B2 B1 B0 Output Mode Control MONO+6d B ...
Page 31 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Global Control Register Table 10. Global Control Register REGISTER B7 B6 B5 B4 B3 B2 B1 B0 Global Control Register SHDN I...
Page 32 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Single-Ended Input cally 300Hz to 3.5k Hz). In addition, speakers used in The MAX9775/MAX9776 can be configured as a sing...
Page 33 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Charge-Pump Capacitor Selection Connect all of the power-supply inputs (CPVDD, VDD, Use capacitors with an ESR less than ...
Page 34 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Pin Configurations TOP VIEW (BUMPS ON BOTTOM) C1P CPGND C1NCPVDD CPVSS HPL C1P CPGND C1NCPVDD CPVSS HPL CL_H VBIAS INC1CL...
Page 35 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the l...
Page 36 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specification...
Page 37 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specification...
Page 38 2 x 1.5W, Stereo Class D Audio Subsystem with Direct Drive Headphone Amplifier Revision History REVISION REVISION PAGES DESCRIPTION NUMBER DATE CHANGED 3/07 Initial release 7/07 Initial release of MAX...

Manual Details

Brand Audio
Pages 38
File Size 652.71 KB
Published May 15, 2026
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Frequently Asked Questions

What unique features improve sound quality?

Features include DirectDrive architecture, 3D Stereo Enhancement (MAX9775 only), and Click-and-Pop suppression.

Can these amplifiers run on a single power supply?

Yes, they operate using single supplies ranging from 2.7V to 5.5V, eliminating the need for large DC-blocking capacitors.

What are the specified maximum operating temperatures?

All devices are specified over an extended temperature range of -40°C to +85°C.

What is the typical audio output power per channel?

The chips deliver 1.5W stereo output into a 4Ω load from a 5V supply.