Audio Product Guide - Maxim Integrated · • The automatic level control (ALC) has a battery...

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Product Guide

Audio

13th Edition

Table of Contents

2

www.maximintegrated.comAudio Product Guide

Speaker Amplifiers 3 Digital Input Class D Amplifiers 4 Tiny Speaker Amplifier Solution 5 Boosted Class D and Class DG Amplifiers 6 High-Power Speaker Amplifiers

Headphone Amplifiers 8 2VRMS DirectDrive Amplifier 9 Class H Headphone Amplifiers

Codecs 10 Codec Design Tools 11 Audio Codec with FlexSound Processor

12 Selection Guide

17 Class A–Class H Amplifier Tutorial

www.maximintegrated.com Audio Product Guide

3

Plug-and-Play Digital Input Class D AmplifiersThe MAX98355A/MAX98355B and the MAX98356 are easy-to-use digital speaker amplifiers that improve audio quality, simplify design, and hasten time to market. They offer very high wideband jitter tolerance, low THD+N, and low output offset voltage to deliver superior performance and audio quality.

These devices are easy to use because unique internal circuitry allows the parts to self-configure for sample rate and bit depth. This functionality eliminates the need for programming. The MAX98355A/MAX98355B and the MAX98356 do not require an MCLK signal, simplifying routing and allowing for a small 9-bump package. They also do not require a separate digital supply rail, thereby eliminating the need for an additional capacitor.

MAX98355A/MAX98355B• Single-supply operation (2.5V to 5.5V)• 3.2W output power into 4Ω at 5V• 2.2mA quiescent current• 92% efficiency (RL = 8Ω, POUT = 900mW, VDD = 3.7V)• 25µVRMS output noise (AV = 15dB)• Low 0.013% THD+N at 1kHz• No MCLK required• Supports left, right, or (left + right)/2 outputs

MAX98356• Single-supply operation (2.5V to 5.5V)• 3.2W output power into 4Ω at 5V• 1.7mA quiescent current• 92% efficiency (RL = 8Ω, POUT = 900mW, VDD = 3.7V)• 29µVRMS output noise (AV = 6dB)• Low 0.013% THD+N at 1kHz• Supports PDM_CLK rates of 1.8MHz to 4.32MHz

and 5.28MHz to 8.6MHz• Supports left, right, or (left + right)/2 outputs

DACCLASS DOUTPUT

STAGE

DIGITALAUDIO

INTERFACE

PCMINPUT

GAINCONTROL

SHUTDOWNAND

CHANNELSELECT

MAX98355AMAX98355B

DACCLASS DOUTPUT

STAGE

DIGITALAUDIO

INTERFACE

PDMINPUT

GAINCONTROL

SHUTDOWNAND

CHANNELSELECT

MAX98356


4

Tiny Speaker Amplifiers for Space-Constrained ApplicationsSmall Size to Fit Your ApplicationMaxim continues to lead the industry in innovative packaging technology that enables the smallest audio solutions. The Maxim family includes the industry's smallest Class AB and D amplifiers on the market in tiny 0.3mm pitch, 1mm x 1mm, 9-bump WLP packages.

3DMI Process Technology3DMI process technology enables us to stack passive components directly onto the active substrate without increasing package height and area. This technology is used to integrate highly linear, input capacitors into the MAX98314, further reducing solution size, to save at least 25% more board space and provide excellent THD+N, PSRR, and CMRR performance at low frequencies. 3DMI technology opens doors to countless possibilities for future solutions.

MAX98314• 0.95mA at 3.7V low quiescent current • 3.2W into 4Ω, VPVDD = 5V• 19µV ultra-low noise• Spread spectrum and active emissions limiting

GAIN CONTROL

CLASS DMODULATOR

AND H-BRIDGE

CIN

CIN

MAX98314

9-BUMP

1m m x 1 m m

Part Amplifier Class Power at 10% THD+N (W), RL = 4Ω Integrated Input Capacitors Package (mm x mm)

MAX98304 Class D 3.2 1 x 1

MAX98309 Class AB 2.7 1 x 1

MAX98310 Class AB 1.4 1 x 1

MAX98314 Class D 2.7 1 x 1


5

CONTROL

DIFFERENTIALINPUT

BOOST CONVERTER

GAINOUTPUT

STAGE

BATTERY

SPKP

SPKN

PVDD

VCCOUT

LXVBAT

AGND SPKPGNDBSTPGNDC4 A4 D1, C2

D3

RKNEE B3

GAIN B2

SDSPK C3

SDBST D4

B4 A3A2

A1

B1

C1

INP D2

INN

MAX98500

Multiple Power Supply Voltages

Louder, Clearer Audio with Extended Battery LifeThe MAX98500/MAX98502 boosted Class D amplifiers and the MAX98307/MAX98308 Class DG amplifiers are designed for battery-operated portable devices.

MAX98500/MAX98502• Integrated boost converter to provide a constant output power for louder audio output over a wide range of battery supply voltages.• The automatic level control (ALC) has a battery tracking function that reduces output swing as the supply voltage drops,

preventing collapse of the battery voltage.

MAX98307/MAX98308• Class DG multilevel architecture offers highly efficient, high-power audio portable solutions.• Class DG multilevel architecture combines Class D switching output efficiency and Class G supply level shifting to more

efficiently supply the required signal power. This allows for optimal efficiency over a wide output range. See the Class A– Class H Amplifier Tutorial.

A Class DG amplifier improves upon Class AB by using a different power supply voltage depending on the signal level. Two or more voltages can be used, but all the voltages are available all the time. This is done by generating additional voltages from the single input voltage.


6

No EMI Problems with Maxim's Class D AmplifiersFilterless Class D Amplifiers Provide the Output Power You Need With No EMI HasslesMaxim’s Class D amplifiers use patented spread-spectrum modulation techniques in conjunction with sophisticated edge-rate control technology to minimize EMI emissions. With no need for LC filters to clean up RF interference, your design will be compact, deliver solid performance, and cost less.

20W Stereo/10W Mono Amplifier with I2C Volume Control MAX9744/MAX9768• 4.5V to 14V supply voltage range• Filterless, low-EMI modulation scheme • I2C or analog volume control • High efficiency eliminates bulky heatsinks• High PSRR, low THD+N

INR-

INR+

OUTR-

OUTR+PGA

CLIPPINGLIMITER

CLASS DMODULATOR

AND H-BRIDGE

INL-

INL+

OUTL-

OUTL+

MONO

PGACLIPPINGLIMITER

CLASS DMODULATOR

AND H-BRIDGE

MAX98400AMAX98400B

Differential Input, Power Limiting, Thermal Foldback, Excellent EMI Performance, and Clipping LimiterMAX98400A/MAX98400B• Wide 8V to 28V single-supply voltage range• 2x20W into 8Ω or 1x40W into 4Ω (MAX98400A) or

2x12W into 8Ω (MAX98400B)• Optional 5V supply for efficiency optimization• Integrated edge rate control for low EMI for filterless

operation• Clipping and power limiting• Two-pin, eight gain selector (9.1dB to 32.9dB)• Thermal foldback avoids thermal shutdown

VOLUMECONTROL

MUTE

SHUTDOWN

CLA

SS D

CLA

SS D

AUDIOINPUT

AUDIOINPUT

BIAS

OSCILLATORSYNCOUTSYNC

ANALOG OR I2C VOLUMECONTROL MAX9744


7

Industry’s Lowest Supply CurrentThe MAX98300 and the MAX98302 represent a substantial advancement in Class D amplifier power consumption by achieving supply current as low as 600µA. Critical to maximizing battery life in today’s portable products, this low supply current has been achieved without sacrificing EMI suppression, clipping behavior, noise performance, and click-and-pop level. In fact, these have all been improved.

Overdrive is No Problem—These Amplifiers Clip CleanlyIn small consumer devices, both speakers and amplifiers are driven hard to yield the highest sound pressure level (SPL) possible. As a result, the amplifier may be heavily clipped. Many amplifier designs, particularly Class D designs, contribute additional high-frequency distortion artifacts that are far more objectionable than a cleanly clipped signal. The MAX98300 and the MAX98302 have been carefully designed to ensure clean recovery from clipping events.

Low VOS for Low Click-and-Pop NoiseClick-and-pop performance becomes important as we aggressively manage the power of amplifiers with frequent turn-on and turn-off cycles. If a pop or click is heard each time, it is annoying for the user. The MAX98300 has a very low offset voltage, and carefully addresses other sources of click-and-pop noise to ensure the best performance

Maxim’s Class D Amplifier FamilyExtend Battery Life While Reducing EMI, Clipping, Noise, and Clicks and Pops

Supply Current vs. Supply Voltage

SUPPLY VOLTAGE (V)

SUPP

LY C

URR

ENT

(mA

)

4.0 4.5 5.0 5.53.53.0

2.5

2.0

1.0

0.5

1.5

4.0

3.5

3.0

02.5

COMPETITION

MAX98300

MAX98300 Heavy Clipping Recovery

VOUT

SHDN

1mV (typ)

MAX98300 Filtered Output Voltage vs. SHDN

50.0

40.0

30.0

20.0

AM

PLIT

UD

E (d

BμV/

m)

10.0

0.0

-10.030.0 100.0 200.0 300.0 400.0 500.0

FREQUENCY (MHz)600.0 700.0 800.0 900.0 1000.0

MAX98300 EMI Spectrum (~24in Cable)

MAX98300

EN55022B LIMIT


8

2VRMS DirectDrive Headphone AmplifierThe MAX97220A-MAX97220E deliver excellent audio quality and performance.

• Differential input reduces common input and ground noise• Output power 125mW into 32Ω with a 5V supply• 3VRMS output drive into 1kΩ with a 5V supply• 2VRMS output drive into 600Ω with a 3.3V supply• Fixed or externally adjustable gain with no clicks or pops• Wide 2.5V to 5.5V operating range• DirectDrive® outputs eliminate DC-blocking capacitors• High 112dB SNR and 90dB THD+N across audio bandwidth• Ground sense reduces noise, distortion, and crosstalk

LEFTAUDIOINPUT

RIGHTAUDIOINPUT

RIN

RF

RFINL-

OUTL

OUTR

INL+

INR+

RF

RF

RF

INR-

RIN

RIN

RIN

MAX97220AMAX97220BMAX97220E

LEFTAUDIOINPUT

RIGHTAUDIOINPUT

RIN

OUTL

SGND

SGND

OUTR

RF

RF

RF

RIN

RIN

RIN

MAX97220CMAX97220D

INL-

INL+

INR+

INR-


9

Ultra-Low Power Headphone AmplifiersLow-Power Class H Headphone Amplifiers Offer Higher EfficiencyClass H amplifiers provide nearly 2x higher efficiency than the closest competitive Class G headphone amplifiers. Class H amps modulate the supply voltage to minimize voltage drop across the output devices by using either multiple supply voltages or an infinitely adjustable power supply.

Enjoy Longer Battery Life Using Second-Generation, Dual-Mode, DirectDrive TechnologyBased on Maxim’s proprietary DirectDrive technology, our dual-mode DirectDrive II Class H amplifiers save power by switching between two supply voltages. The dual-mode charge pump uses ±0.9V rails when the output signal is small, only switching to ±1.8V supply voltage when more output power is needed. This technology renders a continuous signal without the glitches seen in Class G amplifiers.

32ms+1.8V

+0.9V

VTH_H

VTH_L

-0.9V

-1.8V

HPVDD

HPVSS

OUTPUTVOLTAGE

32ms

TIME

0.05% THD+N performance

CHARGEPUMP

MAX97200

AUDIOSOURCE

LEFT AUDIO INPUT

SHDN

RIGHT AUDIO INPUT

LEFT AUDIO OUTPUT

RIGHT AUDIO OUTPUT

No clicks or pops

Dynamic,Class H dual-mode

charge pump


10

Customized Audio Made EasyMAX98089, MAX98090*, and MAX98091* Codec Design ToolMaxim’s evaluation kit and intuitive user interface allow you to tune flexible, feature-rich codecs to the desired performance quickly and easily. Optimize parametric EQ, automatic level control, speaker excursion limiter, speaker distortion THD limiter, microphone AGC, and microphone noise gate.

1) Download the codec GUI software.

2) Plug evaluation kit into your laptop.

3) Connect your headphones and speakers to the evaluation kit.

4) Graphically route and tune audio as you listen; register is set automatically.

Software drivers are available for Linux and other OS platforms.

*Future product—contact factory for availability.


11


Audio Codecs with Integrated Digital Signal ProcessingThe MAX98089 and the MAX98090* full-featured audio codecs improve audio performance and prevent speaker damage. The parts feature Maxim’s proprietary FlexSound™ audio technology that optimizes the signal level and frequency response while limiting the maximum distortion and power at the output. This technology improves loudspeaker performance and prevents speaker damage.

MICROPHONE 1PREAMP/PGA

(DIFFERENTIAL)

• DIGITAL BIQUAD FILTER (RECORD)• 7-BAND PARAMETRIC

EQUALIZER (PLAYBACK)• DYNAMIC RANGE CONTROL (PLAYBACK)• DIGITAL FILTERING• DIGITAL GAIN/LEVEL

CONTROL

FlexSound DSP

LINE INPUT A PGA(DIFFERENTIAL OR

SINGLE-ENDED)

MICROPHONE 2PREAMP/PGA

(DIFFERENTIAL)

LINE INPUT B PGA(DIFFERENTIAL OR

SINGLE-ENDED)

6

5

STEREO DIGITALMICOPHONE

POWERMANAGEMENT

CONTROLREGISTERS

I2C

DIGITAL AUDIOINTERFACE

I2S/TDMBATTERY 1.2V1.8V

JACK DETECTION

4

3

2

1

CHARGE PUMP

STEREOADC

STEREODAC

MAX98090*

STEREO HEADPHONECLASS H AMPLIFIER

(SINGLE-ENDED)

SPEAKER RIGHTCLASS D AMPLIFIER

(DIFFERENTIAL)

SPEAKER LEFTCLASS D AMPLIFIER

(DIFFERENTIAL)

SPEAKER LEFTCLASS D AMPLIFIER

(DIFFERENTIAL)

STEREO LINE OUTPUTCLASS AB AMPLIFIER

(SINGLE-ENDED)OR

3-POLE (TRS) 4-POLE (TRRS)

OR

ANALOGMICROPHONE

DIGITALMICROPHONE

LINE INPUT

OR

OR

ANALOGMICROPHONE

LINE INPUT

OR

ANALOGMICROPHONE

LINE INPUT

OR

HEADPHONESOR

HEADSET

LINE OUTPUT

RECEIVER/EARPIECE

OR

SPEAKERLEFT/RIGHT

Feature MAX98089 MAX98090*/MAX98091*

Parametric EQ 5 band 7 band

Distortion limiter Yes Yes

Excursion limiter Yes Yes

Integrated speaker amplifiers Yes Yes

Integrated headphone amplifiers Yes Yes

Analog microphone inputs 2 3/3

Digital microphone inputs 2 2/4

Line inputs/line outputs 4 6

Jack detection Yes Yes

Digital audio interfaces 2 1

Automatic level control Yes Yes

Power limiter Yes Yes

Microphone AGC Yes No

Microphone noise gate Yes No


12

PartSupply Voltage

(V)

Output Power at 1% THD+N (W) Features

Package (mm x mm)

8Ω 4Ω Gain Other

MAX9710 4.5 to 5.5 2 x 1.5 2 x 2.6 Adj Mute 20-TQFN (5 x 5)

MAX9711 4.5 to 5.5 1.5 2.6 Adj Mute 12-TQFN (4 x 4)

MAX9716 MAX9717 2.7 to 5.5 1.1 1.4 Adj

Fixed Headphone sense 8-TDFN (3 x 3), 9-UCSP™ (1.5 x 1.5)

MAX9718MAX9719

2.7 to 5.51.1 1.4 Adj

Fixed Differential inputs 10-TDFN (3 x 3), 9-UCSP (1.5 x 1.5)2 x 1.1 2 x 1.4

MAX9730 2.7 to 5.5 2.4 — Adj Charge-pump-boosted amp for dynamic speakers 28-TQFN (4 x 4), 20-WLP (2 x 2.5)

MAX9738 2.7 to 5.5 16VP-P — Adj DC-DC-boosted amp for ceramic speakers 20-WLP (2 x 2.5)

MAX9788 2.7 to 5.5 20VP-P — Adj Charge-pump-boosted amp for ceramic speakers 28-TQFN (4 x 4), 20-WLP (2 x 2.5)

MAX98309 MAX98310

2.2 to 5.5 1.4 2.1Adj

FixedDifferential inputs 9-WLP (1 x 1)

Class AB Speaker Amplifiers

Part Supply Voltage (V)


Package (mm x mm)

8Ω 4Ω Gain Other

MAX9708 10 to 18 2 x 20 40 Pin programmable Programmable thermal flag 56-TQFN (8 x 8)

MAX9709 10 to 22 2 x 25 50 Pin programmable Programmable thermal flag 56-TQFN (8 x 8)

MAX9736A 8 to 28 2 x 15 30 Set by external resistors Mute function 32-TQFN (7 x 7)

MAX9736B 8 to 28 2 x 6 12 Set by external resistors Mute function 32-TQFN (7 x 7)

MAX9737 8 to 28 7.4 14 Set by external resistors Mute function 24-TQFN (4 x 4)

MAX9742 20 to 40 2 x 20 2 x 16 Set by external resistors Single-ended output 36-TQFN (6 x 6)

MAX9744 4.5 to 14 2 x 13 2 x 20 Set by external resistors I2C/analog volume control 44-TQFN (7 x 7)

MAX9768 4.5 to 14 10 — Set by external resistors I2C/analog volume control 24-TQFN (4 x 4)

MAX98400A* 8 to 28 2 x 20 40 Pin programmable Clipping limiter 36-TQFN (6 x 6)

MAX98400B* 8 to 28 2 x 12 — Pin programmable Clipping limiter 24-TQFN (4 x 4)

High-Power, Class D Speaker Amplifiers

*JEITA (Japan Electronics and Information Technology Industries Association) standard, “A Guide to the Safe Use of Secondary Lithium Ion Batteries in Notebook-type Personal Computers”, April 20, 2007.


13



Package (mm x mm)

8Ω 4Ω Gain Input Type

MAX98355A/MAX98355B 2.5 to 5.5 1.4 2.5 3, 6, 9, 12, 15 PCM 9-WLP

(1.3 x 1.5)

MAX98356 2.5 to 5.5 1.4 2.5 3, 6, 9, 12, 15 PDM 9-WLP (1.3 x 1.5)

Digital Input Class D Speaker Amplifiers



Package (mm x mm)

8Ω 4Ω

Spread-Spectrum/Edge-Rate

Control

Gain Differential Input

MAX9715 4.5 to 5.5 2 x 1.4 2 x 2.3 /— Pin programmable 16-TQFN (5 x 5)

MAX9759 3.0 to 5.5 1.4 2.6 /— Pin programmable 16-TQFN (4 x 4)

MAX9830 2.6 to 5.5 1.3 1.7 / Fixed 8-TDFN (2 x 2), 9-WLP (1.2 x 1.2)

MAX98300 2.6 to 5.5 1.3 2.1 / Pin programmable 8-TDFN (2 x 2), 9-WLP (1.2 x 1.2)

MAX98302 2.6 to 5.5 2 x 1 2 x 2 / Pin programmable 14-TDFN (3 x 3)

MAX98304 2.6 to 5.5 1.4 2.6 / Pin programmable 9-WLP (1.0 x 1.0)

MAX98306 2.6 to 5.5 2 x 1.4 2 x 2.4 / Pin programmable 14-TDFN (3 x 3)


MAX98500 2.5 to 5.5 1.7 — / Pin programmable 16-WLP (2.1 x 2.1)


Low-Power, Class D Speaker Amplifiers (Filterless)


14



Supply Current

(mA)

Output Offset (mV)

Output Power at 1% THD+N (mW)

Features Package (mm x mm)

32Ω 16Ω

MAX4409 1.8 to 3.6 5.0 0.5 65 80 Ground noise rejection 20-TQFN (4 x 4)

MAX4410/ MAX4411 1.8 to 3.6 5.0 0.5 65 80 Ultra-low distortion 16-UCSP (2 x 2), 20-TQFN (4 x 4)

MAX9722 2.4 to 5.5 5.5 0.5 130 70 Differential inputs 16-TQFN (3 x 3)

MAX9724 2.7 to 5.5 3.5 1.5 63 42 Industry's lowest RF susceptibility 12-TQFN (3 x 3), 12-UCSP (1.5 x 2)

MAX9820 2.7 to 5.5 3.0 0.1 95 70 Windows Vista® premium mobile compliant 10-TDFN (3 x 3)

MAX97200 1.6 to 2 1.15 0.1 34 40 Lowest quiescent current 12-WLP (1.7 x 1.3)

MAX97220–MAX97220E 2.5 to 5.5 5.0 0.35 125 110 2VRMS into 600Ω

differential outputs 16-TQFN (3 x 3 x 0.8)

Capless, DirectDrive Headphone Amplifiers

Part

Supply Voltage (V) 48kHz DAC Playback

Power Consumption

(mW)

Playback Dynamic

Range (dB)

Features

Package (mm x mm)Core I/O Analog I/O

Digital Audio

Interface

MCLK Range (MHz)

Supported Sample Rates (kHz)

MAX9850 (DAC)

1.8 to 3.6

1.8 to 3.6 10.1 91 2 line inputs, 2 line outputs,

2 headphone amps I2S 8.5 to 40 8 to 48 28-TQFN (5 x 5)

MAX9856 (codec)

1.7 to 3.6

1.7 to 3.6 9 91

3 line inputs, 3 microphone inputs, 2 line outputs, 2 headphone amps

I2S/TDM 10 to 60 8 to 96 40-TQFN (6 x 6)

MAX9860 (codec)

1.7 to 1.9

1.7 to 3.6 4.5 90 2 microphone inputs,

1 headphone amp I2S/TDM 10 to 60 8 to 48 24-TQFN (4 x 4)

MAX9867 (codec)

1.65 to 1.95

1.65 to 3.6 5.5 92

2 line inputs, 2 microphone inputs, 2 headphone amps, 1 aux ADC

I2S/TDM 10 to 60 8 to 48

30-WLP (2 x 2.5),

32-TQFN (5 x 5)

MAX98089 (codec)

1.65 to 3.6

1.65 to 2.0 5.5 101

4 line inputs, 3 microphone inputs, 2 headphone amplifiers, 2 speaker amplifiers

I2S/TDM 10 to 60 8 to 96 63-WLP,

56-TQFN

MAX98090* (codec)

1.65 to 3.6 1.65 to 2 3.6 102


I2S/TDM 8 to 96 8 to 96 49-WLP,

40-TQFN

MAX98091* (codec)

1.65 to 3.6 1.65 to 2 3.6 102


I2S/TDM 8 to 96 8 to 96 56-WLP

Audio Data Converters


15

PartSupply Voltage

(V)

Supply Current

(µA)

Input-Noise

Voltage Density

(nV/√Hz)

Features

Package (mm x mm)

InputsGain Shutdown

ModeSingle- Ended Differential

MAX4060 4.5 to 5.5 750 100 1 1 Adj 8-TDFN (3 x 3)

MAX4061 2.4 to 5.5 750 20 1 1 0dB, 20dB, 40dB 8-TDFN (3 x 3)

MAX4063 2.4 to 5.5 750 12 1 1 Adj 16-TQFN (4 x 4)

MAX4465/MAX4466 2.4 to 5.5 24 80 1 Adj 5-SC70 (2 x 2), 5-SOT23 (3 x 3)

MAX9812L/MAX9813L 2.7 to 3.6 230 40 2 20dB

6-SC70 (2 x 2.1) (MAX9812), 8-SOT23 (3 x 3) (MAX9813)

MAX9812H/MAX9813H 4.5 to 5.5 230 40 2 20dB

6-SC70 (2 x 2.1) (MAX9812), 8-SOT23 (3 x 3) (MAX9813)

MAX9814 2.7 to 5.5 3100 30 1 Automatic gain control 14-TDFN (3 x 3)

Microphone Amplifiers With Integrated Mic Bias

Part Supply Voltage (V) Description Package (mm x mm)

MAX9890 2.7 to 5.5 Headphone-amp click-pop suppressor 8-TDFN (3 x 3), 9-UCSP (1.5 x 1.5)

MAX9892 1.7 to 3.6 Audio shunt-mode click-pop suppressor 6-UCSP (1 x 1.5), 6-µDFN (2 x 2)

MAX4744 1.8 to 5.5 Dual SPDT audio switch 10-µDFN (2 x 2)

MAX4764 1.8 to 5.5 Dual SPDT audio switch 10-TDFN (3 x 3), 10-UCSP (1.5 x 2)

MAX4993/MAX4994 1.8 to 5.5 DPDT audio switch 10-UTQFN (1.4 x 1.8)

MAX9895A* 2.5 to 4.5 Active noise-cancellation solution for stereo headphones 36-WLP (2.5 x 2.5 x 0.4), 40-TQFN (5 x 5)

Specialty Audio Devices



16


Output Power at 1% THD+N* Features

Package (mm x mm)

HP 32Ω (mW)

HP 16Ω

(mW)

SP 8Ω (W)

SP 4Ω (W)

Gain/Volume Control

Speaker Amplifier Other

MAX9775 2.7 to 5.5 50 60 2 x 1.1 2 x 1.5 I2C Stereo Class D

6 single-ended or 3 differential

audio inputs, 3D sound

36-UCSP (3 x 3)

MAX9776 2.7 to 5.5 50 60 1.1 1.5 I2C Mono Class D



36-UCSP (3 x 3), 32-TQFN (5 x 5)

MAX9789 4.5 to 5.5 55 100 2 x 1 2 x 2 Pin programmable

Stereo Class AB Integrated LDO 32-TQFN (5 x 5)

MAX9791 2.7 to 5.5 180 100 2 x 1.2 2 x 1.7 Adj Stereo Class DWake-on-beep, ground sense,

integrated LDO28-TQFN (4 x 4)

MAX9792 2.7 to 5.5 180 100 1.5 2.5 Adj Mono Class DWake-on-beep, ground sense,

integrated LDO28-TQFN (4 x 4)

MAX9796 2.7 to 5.5 50 60 1.3 2.3 I2C Mono Class D



32-TQFN (5 x 5)

MAX9877 2.7 to 5.25 27 53 0.725 0.825 I2C Mono Class D2 stereo or 2

mono differential audio inputs

20-WLP (2 x 2.5)

MAX9879 2.7 to 5.5 54 58 2 x 0.715 2 x 0.825 I2C Stereo Class D

2 stereo or 2 mono differential

audio inputs30-UCSP (2.5 x 3)

MAX97000 2.7 to 5.5/ 1.7 to 2.0 23 40 0.930 I2C Mono Class D

Integrated LDO, bypass switch, THD

limiter, Class H headphone amp

25-WLP (2 x 2 x 0.4)

MAX97001 2.7 to 5.5/ 1.6 to 2.0 34 43 0.710 I2C Mono Class D

Bypass switch, THD limiter,

Class H headphone amp

20-WLP (2 x 2.5)

MAX97003 2.7 to 5.5 32 42 1 2.5 I2C Mono Class D

Class H headphone amp, 2 stereo single-

ended/mono differential

inputs

20-WLP (2 x 2.5)

Integrated Audio Subsystems

*HP = headphone, SP = speaker


17

Class A–Class H Amplifier Tutorial

Class AThe simplest type of amplifiers, Class A amplifiers, are those in which the output transistors conduct (i.e., do not fully turn off), irrespective of the output signal waveform. This type of amplifier is typically associated with high linearity, but low efficiency.

Class ABA combination of Class A and Class B, the Class AB amplifier has higher efficiency than Class A, but less distortion than Class B. This performance is achieved by biasing both transistors to conduct near zero signal output—the point where Class B amplifiers introduce nonlinearities. They then transition to Class B for large excursions. Thus, for small signals, both transistors are active, acting like a Class A amplifier. For large signal excursions, only one transistor is active for each half of the waveform, acting like a Class B amplifier.

CLASS DMODULATOR

MOSFETDRIVER

CLASS DMODULATOR

MOSFETDRIVER

Class BClass B amplifiers are those in which the output transistors only conduct during half (180°) of the signal waveform. To amplify the entire signal, they use two transistors, one conducting for positive output signals and the other conducting for negative outputs. Class B amplifiers are much more efficient than Class A amplifiers, but they have high distortion due to the crossover point at which the two transistors transition from on to off.

Class DClass D amplifiers are those that output a switching waveform at a frequency far higher than the highest audio signal that needs to be reproduced. The lowpass-filtered average value of this waveform corresponds to the actual required audio waveform. These amplifiers are highly efficient (often up to 90% or higher) because the output transistors are either fully turned on or off during operation. This approach completely eliminates the use of the linear region of the transistor, which is responsible for the inefficiency of other amplifier types. Modern Class D amplifiers achieve fidelity comparable to Class AB.

CLASS DMODULATOR

MOSFETDRIVER

CLASS DMODULATOR

MOSFETDRIVER


18

Class A–Class H Amplifier Tutorial (cont.)

+V1

-V1

-V1

+V1

+V1+V2

-V1 -V2

-V1

-V2

+V1

+V2

+V1+V2

-V1 -V2

-V1

-V2

+V1

+V2CLASS D

MODULATORMOSFETDRIVER

Class GClass G amplifiers are similar to Class AB amplifiers, except that they use two or more supply voltages. When operating at low signal levels, the amplifier selects a low supply voltage. As the signal level increases, the amplifier automatically selects the appropriate supply voltage. Class G amplifiers are more efficient than Class AB amplifiers because they use the maximum supply voltage only when required, while a Class AB amplifier always uses the maximum supply voltage.

Class HClass H amplifiers modulate their supply voltage to minimize the voltage drop across the output stage. Implementations range from using multiple discrete voltages to an infinitely adjustable supply. Though similar to the Class G technique of reducing dissipation across output devices, the Class H technique does not require multiple power supplies. Class H amplifiers are generally more complex than other designs, with extra control circuitry required to predict and control the supply voltage.

+V1

-V1

-V1

+V1

+V1+V2

-V1 -V2

-V1

-V2

+V1

+V2

+V1+V2

-V1 -V2

-V1

-V2

+V1

+V2CLASS D


+V1

-V1

-V1

+V1

+V1+V2

-V1 -V2

-V1

-V2

+V1

+V2

+V1+V2

-V1 -V2

-V1

-V2

+V1

+V2CLASS D


Class DGClass DG uses pulse-width modulation (PWM), a rail-to-rail digital output signal with variable duty cycle, to approximate an analog input signal as in a Class D amplifier. The Class DG multilevel output stage also senses the magnitude of the output signal and switches the supply rails as needed to more efficiently supply the required signal power.


19

Theoretical Output PowerThe following figure shows the theoretical output power possible from a range of supply voltages. Output power is specified at 1% and 10% THD+N with 4Ω and 8Ω loads. Real amplifiers will always output less power than shown in this figure.

Output Power vs. Supply Voltage

3

100

4Ω BTL, 10% THD+N

10

1

0.1

8 13 18 23 28

OU

TPU

T PO

WER

(W)

SUPPLY VOLTAGE (V)

4Ω BTL, 1% THD+N

8Ω BTL, 1% THD+N

8Ω BTL, 10% THD+N

Contact Maxim Direct at 1.800.629.4642 or for more information, visit www.maximintegrated.com.

© 2012 Maxim Integrated. All rights reserved. The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc. in the United States and other jurisdictions throughout the world. All other company names may be trade names or trademarks of their respective owners.Rev. 0; December 2012


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