MAXIM MAX9879 Technical data

General Description

The MAX9879 combines a high-efficiency stereo Class D
audio power amplifier with a stereo capacitor-less
DirectDrive®headphone amplifier. Maxim’s filterless class
D amplifiers with active emissions limiting technology pro­vide Class AB performance with Class D efficiency.

The Class D power amplifier delivers up to 715mW from
a 3.7V supply into an 8Ω load with 88% efficiency to
extend battery life. The filterless modulation scheme
combined with active emission limiting circuitry and
spread-spectrum modulation greatly reduces EMI while
eliminating the need for output filtering used in tradition­al Class D devices.

The headphone amplifier delivers up to 58mW from
a 3.7V supply into a 16Ω load. Maxim’s DirectDrive
architecture produces a ground-referenced output from
a single supply, eliminating the need for large DC­blocking capacitors, saving cost, space and compo­nent height.

The device utilizes a user-defined input architecture,
three preamplifier gain settings, an input mixer, volume
control, comprehensive click-and-pop suppression, and
I

2

C control. A bypass mode feature disables the integrat­ed 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 MAX9879.

The MAX9879 is available in a thermally efficient,
space-saving 30-bump UCSP™ package.

Applications

Features

♦ Better than 9dB Margin Under EN 55022 Class B

Limits with No Filter Components

♦ Low RF Susceptibility Design Rejects TDMA

Noise from GSM Radios

♦ Input Mixer with User Defined Input Mode
♦ Stereo 715mW Speaker Output (R

L

= 8Ω,

V

DD

= 3.7V)

♦ Stereo 58mW Headphone Output (16Ω,

V

DD

= 3.7V)

♦ Low 0.04% THD+N at 1kHz (Class D Power

Amplifier)

♦ Low 0.018% THD+N at 1kHz (Headphone

Amplifier)

♦ 88% Efficiency (R

L

= 8Ω, P

OUT

= 750mW)

♦ 1.6Ω Analog Switch for Speaker Amplifier Bypass
♦ High Speaker Amplifier PSRR (72dB at 217Hz)
♦ High Headphone Amplifier PSRR (84dB at 217Hz)
♦ I

2

C Control

♦ Hardware and Software Shutdown Mode
♦ Ultra-Low Click and Pop
♦ Robust Design with Current and Thermal

Protection

♦ Available in Space-Saving Package

5x6 UCSP (2.5mm x 3mm)

MAX9879

Stereo Class D Audio Subsystem

with DirectDrive Headphone Amplifier

________________________________________________________________

Maxim Integrated Products

1

MIXER

PREAMPLIFIER

SINGLE SUPPLY

2.7V TO 5.5V

I2C

INTERFACE

VOLUME

CONTROL

VOLUME

CONTROL

BYPASS

MAX9879

Simplified Block Diagram

OUTL- PVDDL

OUTL+

C1P

1

A

B

C

D

E

2

3

4

PGNDR

RXIN- PGNDL

RXIN+

C1N

PGNDR

GND GND

GND

V

SS

GND

BIAS INB1

INA1

HPL

SCL

56

TOP VIEW

(BUMP SIDE DOWN)

OUTR-

PVDDR

OUTR+

SDA

V

DD

INB2

INA2

HPR

SHDN

V

CCIO

Pin Configuration

19-4436; Rev 0; 2/09

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.

EVALUATION KIT

AVAILABLE

Ordering Information

PART

PIN - PA C K A G E

MAX9879ERV+

30 UCSP (5x6)

+

Denotes a lead(Pb)-free/RoHS-compliant package.

Cell Phones

Portable Multimedia Players

DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.

UCSP is a trademark of Maxim Integrated Products, Inc.

TEMP RANGE

-40°C to +85°C

MAX9879

Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

VDD, PVDDL, PVDDR to GND ..................................-0.3V to +6V

V

DD

, PVDDL to PVDDR .........................................-0.3V to +0.3V

V

DD

to PVDDL .......................................................-0.3V to +0.3V

V

CCIO

to GND...........................................................-0.3V to +4V

PGNDL, PGNDR, to GND......................................-0.3V to +0.3V

PGNDL to PGNDR.................................................-0.3V to +0.3V

V

SS

to GND...............................................................-6V to +0.3V

C1N to GND ................................................(V

SS

- 0.3V) to +0.3V

C1P to GND ...........................................-0.3V to (PVDD_ + 0.3V)

HPL, HPR to V

SS

(Note 1).............................-0.3V to the lower of

(V

DD

- V

SS

+ 0.3V) or +9V

HPL, HPR to V

DD

(Note 2) .........................+0.3V to the higher of

(V

SS

- PVDD_ - 0.3V) or -9V

INA1, INA2, INB1, INB2, BIAS..................................-0.3V to +4V

SDA, SCL, SHDN......................................................-0.3V to +4V

All Other Pins to GND ............................-0.3V to (PVDD_ + 0.3V)

Continuous Current In/Out of PVDD_, PGND_, OUT_ ....±800mA

Continuous Current In/Out of HPR and HPL .....................140mA

Continuous Current In/Out of RXIN+ and RXIN- ...............150mA

Continuous Input Current V

SS

...........................................100mA

Continuous Input Current (All Other Pins) ........................±20mA

Duration of OUT_ Short Circuit

to PGND_ or PVDD_...............................................Continuous

Duration of Short Circuit

Between OUT_+ and OUT_- ..................................Continuous

Duration of HP_ Short Circuit to GND or PVDDL........Continuous

Continuous Power Dissipation (T

A

= +70°C)

5x6 UCSP Multilayer Board

(derate 16.5mW/°C above +70°C).............................1250mW

Junction Temperature......................................................+150°C

Operating Temperature Range ...........................-40°C to +85°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

ELECTRICAL CHARACTERISTICS

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0, volume controls =

0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL or HPR to
GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

(Notes 3, 4)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

Note 1: HPR and HPL should be limited to no more than 9V above VSS, or above PVDD+ 0.3V, whichever limits first.
Note 2: HPR and HPL should be limited to no more than 9V below PV

DD

, or below VSS- 0.3V, whichever limits first.

Analog Supply Voltage Range

Digital Supply Voltage Range V

Quiescent Current I

Shutdown Current I

Turn-On Time t

Input Resistance R

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

,

DD

PVDDR

Guaranteed by PSRR Test 2.7 5.5 V

PVDDL

CCIO

1.7 3.6 V

HP mode, RHP = ∞ 5.6 9.0

DD

SHDN

ON

IN

Stereo SPK mode, R

Mono SPK mode, R

Stereo SPK + HP mode, RHP= R

I

= IDD + I

SHDN

I

+ ICC; TA = +25°C

PVDDL

PVDDR

Time from shutdown or power-on to full
operation

TA = +25°C, preamp = 0dB or +5.5dB 11 21 31

TA = +25°C, preamp = +20dB 3 5.5 8

= ∞ 9.8 18

SPK

= ∞ 6.6 10

SPK

= ∞ 13.2 24

SPK

Software
shutdown

+

Hardware
shutdown

510

0.1 1

10 ms

Preamp = 0 2.3

Preamp = +5.5dB 1.2Maximum Input Signal Swing

Preamp = +20dB 0.230

mA

V

µA

kΩ

P-P

MAX9879

Stereo Class D Audio Subsystem

with DirectDrive Headphone Amplifier

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0, volume controls =

0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL or HPR to
GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

(Notes 3, 4)

Common-Mode Rejection Ratio CMRR

Input DC Voltage IN__ inputs 1.22 1.3 1.38 V

Bias Voltage V

SPEAKER AMPLIFIER

Output Offset Voltage V

Click-and-Pop Level K

Power-Supply Rejection Ratio
(Note 5)

Total Harmonic Distortion + Noise THD+N

Signal-to-Noise Ratio SNR

Output Frequency

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

BIAS

OS

CP

PSRR T

OUT

f

= 1kHz (differential

IN

input mode)

TA = +25°C (volume at mute) ±0.5 ±4 mV

TA = + 25° C ( vol um e at 0d B, E N A = 1 and
E N B = 0 or E N B = 1 and E N A = 0, ΔIN _ = 0)

Peak voltage,

= +25°C

T

A

A-weighted, 32 samples
per second, volume at
mute (Note 5)

= +25°C

A

THD+N ≤ 1%, R
8Ω

f = 1kHz, P
R

= 8Ω

SPK

A-weighted, ENA = 1
and ENB = 0 or ENB = 1
and ENA = 0

A-weighted ENA =
ENB = 1

=

SPK

= 350mW, TA = +25°C,

OUT

Preamp = 0 58

Preamp = 5.5dB 55

Preamp = 20dB 43

1.13 1.2 1.272 V

±4.5 mV

Into shutdown -70

Out of shutdown -70

PVDD_ = V
= 2.7V to 5.5V

f = 217Hz,
100mV

f = 1kHz,
100mV

f = 20kHz,
100mV

VDD = 3.7V 715

VDD = 3.3V 565Output Power P

V

DD

ΔIN_ = 0
(single-ended)

ΔIN_ = 1
(differential)

ΔIN_ = 0
(single-ended)

ΔIN_ = 1
(differential)

DD

ripple

P-P

ripple

P-P

ripple

P-P

= 3.0V 470

50 76

72

68

55

0.04 0.2 %

92

94

88

92

700
±40

dB

dBV

dB

mW

dB

kHz

MAX9879

Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0, volume controls =

0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL or HPR to
GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

(Notes 3, 4)

Current Limit 1.5 A

Efficiency η P

Speaker Gain A

Output Noise

Crosstalk

HEADPHONE AMPLIFIERS

Output Offset Voltage V

Click-and-Pop Level K

Power-Supply Rejection Ratio
(Note 5)

Output Power P

Headphone Gain A

Channel-to-Channel Gain
Tracking

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

OS T

CP

PSRR T

OUT

V

= 600mW, f = 1kHz 88 %

OUT

A-weighted, (ENA = 1 and ENB = 0
or ENA = 0 and ENB = 1), ΔIN_ = 0

OUTL to OUTR, OUTR to OUTL,
f = 20Hz to 20kHz

TA = +25°C (volume at mute) ±0.22 ±0.85 mV

= + 25° C ( V ol um e at 0d B, E N A = 1 and

A

E N B = 0 or E N A = 0 and E N B = 1, ΔIN _ = 0)

Peak voltage, TA = 25°C
A-weighted, 32 samples
per second, volume at
mute (Note 5)

= +25°C

A

THD+N = 1%

T

= +25°C, HPL to HPR, volume at 0dB,

A

ENA=1 and ENB = 0 or ENA = 1 and ENB
= 0, ΔIN_ = 0

17.4 18 18.4 dB

63 µV

75 dB

±1.5 mV

Into shutdown -75

Out of shutdown -75

PVDD_ = V
= 2.7V to 5.5V
f = 217Hz,
V

RIPPLE

= 100mV
f = 1kHz,
V

RIPPLE

= 100mV
f = 20kHz,
V

RIPPLE

= 100mV
RHP = 16Ω 58

R

HP

DD

P-P

P-P

P-P

= 32Ω 54

70 85

84

80

62

2.6 3 3.4 dB

±0.3 ±2.5 %

RMS

dBV

dB

mW

Total Harmonic Distortion + Noise THD+N

RHP = 32Ω

= 10mW, f = 1kHz)

(P

OUT

R

= 16Ω

HP

= 10mW, f = 1kHz)

(P

OUT

0.018

0.037 0.08

%

MAX9879

Stereo Class D Audio Subsystem

with DirectDrive Headphone Amplifier

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0, volume controls =

0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL or HPR to
GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

(Notes 3, 4)

Signal-to-Noise Ratio SNR

Slew Rate SR 0.35 V/µs

Capacitive Drive C

Crosstalk HPL to HPR, HPR to HPL, f = 20Hz to 20kHz 67 dB

Charge-Pump Frequency

VOLUME CONTROL

Minimum Setting _VOL = 1 -75 dB

Maximum Setting _VOL = 31 0 dB

Mute Attenuation f = 1kHz, _VOL = 0

Zero-Crossing Detection Time
Out

ANALOG SWITCH

On-Resistance R

Total Harmonic Distortion + Noise

Off-Isolation

DIGITAL INPUTS (SDA, SCL, SHDN)

Input Voltage High (SDA, SCL) V

Input Voltage Low (SDA, SCL) V

Input Hysteresis (SDA, SCL) V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

L

ON

IH

IL

HYS

A-weighted,
R

= 16Ω

HP

ZCD = 1 60 ms

I

= 20mA,

RXIN__

RXIN_ = 0 and V
BYPASS = 1

V

DIFRXIN

V

CMRXIN

f = 1kHz, BYPASS = 1

BYPASS = 0, RXIN+ and RXIN- to GND =
50Ω, R

SPK

speaker output signal

ENA = 1 and
ENB = 0 or
ENA = 1 and
ENB = 0

ENA = 1 and
ENB = 1

DD,

= 2V
= VDD/2,

,

P-P

= 8Ω, f = 10kHz, referred to

PGAIN_ = 00 0

PGAIN_ = 01 5.5Input Gain Input A or B

PGAIN_ = 10 20

Speaker 100

Headphone 110

TA = +25°C 2.4 4

= T

T

A

MIN

Series resistance is
10Ω per switch

No series resistors 0.3

ΔIN_ = 0 98

ΔIN_ = 1 98

ΔIN_ = 0 96

ΔIN_ = 1 96

100 pF

350

±20

to T

MAX

0.3 0.25 %

88 dB

0.7 x

V

CCIO

200 mV

5.2

0.3 x

V

CCIO

dB

kHz

dB

dB

Ω

V

V

MAX9879

Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier

6 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0, volume controls =

0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL or HPR to
GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

(Notes 3, 4)

Input Voltage High (SHDN) V
Input Voltage Low (SHDN) V
Input Hysteresis (SHDN) V

SDA, SCL, SHDN Input
Capacitance

Input Leakage Current I

Input Leakage Current I

DIGITAL OUTPUTS (SDA open drain)

Output Low-Voltage SDA V

Output High-Voltage SDA V

Output Fall Time SDA t

2-WIRE INTERFACE TIMING

External Pullup Voltage Range
(SDA and SCL)

Serial-Clock Frequency f

Bus Free Time Between STOP
and START Conditions

START Condition Hold t

START Condition Setup Time t

Clock Low Period t

Clock High Period t

Data Setup Time t

Data Hold Time t

SCL/SDA Receiving Rise Time t

SCL/SDA Receiving Fall Time t

SDA Transmitting Fall Time t

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

1.4 V

0.4 V

100 mV

10 pF

V

-

CCIO

0.4

250 ns

HYS

C

IN

IN

OL

OH

OF

IH

IL

IN

SDA, SCL, SHDN, TA = +25°C ±1.0 µA

V

= 0, TA = +25°C ±1.0 µA

CCIO

I

= 3mA 0.4 V

SINK

I

= 3mA

SINK

V

to V

H(MIN)

= 10pF to 400pF, I

bus capacitance

L(MAX)

SINK

= 3mA

1.7 3.6 V

SCL

t

BUF

HD:STA

SU:STA

LOW

HIGH

SU:DAT

HD:DAT

R

F

F

(Note 6)

V

=1.8V (Note 6)

CCIO

V

= 3.6V (Note 6)

CCIO

DC 400 kHz

1.3 µs

0.6 µs

0.6 µs

1.3 µs

0.6 µs

100 ns

0 900 ns

20 +

0.1 x C

20 +

0.1 x C

20 +

0.1 x C

20 +

0.05 x C

B

B

B

B

300 ns

300 ns

250

250

V

ns

MAX9879

Stereo Class D Audio Subsystem

with DirectDrive Headphone Amplifier

_______________________________________________________________________________________ 7

Note 3: All devices are 100% production tested at TA= +25°C. All temperature limits are guaranteed by design.
Note 4: Class D amplifier testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For

R

SPKR

= 8Ω, L = 68mH.

Note 5: Amplifier inputs are AC-coupled to GND.
Note 6: C

B

is in pF.

ELECTRICAL CHARACTERISTICS (continued)

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0dB, volume controls =

0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL or HPR to
GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

(Notes 3, 4)

Set-Up Time for STOP Condition t

Pulse Width of Spike Suppressed t

Capacitive Load for Each Bus
Line

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SU:STO

SP

C

B

0.6 µs

050ns

400 pF

MAX9879

Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier

8 _______________________________________________________________________________________

Typical Operating Characteristics

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0dB, volume con-

trols = 0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL
or HPR to GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= +25°C, unless otherwise noted.)

GENERAL

SUPPLY CURRENT vs. SUPPLY VOLTAGE

10

8

6

4

SUPPLY CURRENT (mA)

2

0

2.7 5.5
SUPPLY VOLTAGE (V)

HEADPHONE MODE

3.93.53.1 4.3 4.7 5.1

MAX9879 toc01

SUPPLY CURRENT (mA)

SUPPLY CURRENT vs. SUPPLY VOLTAGE

16

14

12

10

8

6

4

2

0

STEREO-SPEAKER MODE

2.7 5.5

3.93.53.1 4.3 4.7 5.1

SUPPLY VOLTAGE (V)

20

18

MAX9879 toc02

16

14

12

10

SUPPLY CURRENT (mA)

SUPPLY CURRENT vs. SUPPLY VOLTAGE

HEADPHONE + STEREO-SPEAKER MODE

8

6

4

2.7 5.5

3.93.53.1 4.3 4.7 5.1

SUPPLY VOLTAGE (V)

MAX9879 toc03

SUPPLY CURRENT vs. SUPPLY VOLTAGE

16

SOFTWARE-SHUTDOWN MODE

14

12

10

8

6

SUPPLY CURRENT (µA)

4

2

0

2.7 5.5

3.93.53.1 4.3 4.7 5.1

SUPPLY VOLTAGE (V)

50

MAX9879 toc04

40

30

20

SUPPLY CURRENT (nA)

10

SUPPLY CURRENT vs. SUPPLY VOLTAGE

HARDWARE-SHUTDOWN MODE

0

2.7 5.5

3.93.53.1 4.3 4.7 5.1

SUPPLY VOLTAGE (V)

MAX9879 toc05

ATTENUATION (dB)

VOLUME LEVEL vs. VOLUME STEP

100

90

80

70

60

50

40

30

20

10

0

032

VOLUME STEP

fIN = 1kHz

MAX9879 toc06

20 2812 1648 24

MAX9879

Stereo Class D Audio Subsystem

with DirectDrive Headphone Amplifier

_______________________________________________________________________________________ 9

Typical Operating Characteristics (continued)

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0dB, volume con-

trols = 0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL
or HPR to GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= +25°C, unless otherwise noted.)

SPEAKER AMPLIFIERS (Headphone Disabled)

EFFICIENCY vs. OUTPUT POWER

MAX9879 toc12

OUTPUT POWER (mW)

EFFICIENCY (%)

700400 800600200100 300 500

50

70

80

20

60

10

30

40

90

100

0

0 900

fIN = 1kHz, RL = 8Ω

10

1

THD+N (%)

0.1

0.01

0.01 100

THD+N vs. FREQUENCY SPEAKER

PVDD_= 3.7V

= 8Ω

R

L

OUTPUT POWER = 200mW

OUTPUT POWER = 600mW

10.1 10

FREQUENCY (kHz)

THD+N vs. OUTPUT POWER

10

PVDD_ = 3.0V

= 8Ω

R

L

1

fIN = 6kHz

MAX9879 toc07

THD+N vs. FREQUENCY SPEAKER

10

PVDD_= 3.0V

= 8Ω

R

L

1

THD+N (%)

0.1

0.01

OUTPUT POWER = 100mW

OUTPUT POWER = 400mW

0.01 100

MAX9879 toc10

10.1 10

FREQUENCY (kHz)

10

1

MAX9879 toc08

PVDD_ = 3.7V

= 8Ω

R

L

LEFT SPEAKER ONLY

fIN = 6kHz

10

PVDD_ = 3.7V

= 8Ω

R

L

1

THD+N (%)

0.1

0.01
0 1000600

fIN = 6kHz

fIN = 20Hz

OUTPUT POWER (mW)

THD+N vs. OUTPUT POWER

THD+N vs. OUTPUT POWER

fIN = 1kHz

800200 400

MAX9879 toc11

MAX9879 toc09

THD+N (%)

0.1

0.01
0 700300 400100

fIN = 20Hz

200 500 600

OUTPUT POWER (mW)

fIN = 1kHz

THD+N (%)

0.1

0.01
0 1000800200 400

fIN = 20Hz

OUTPUT POWER (mW)

fIN = 1kHz

600

OUTPUT POWER vs. SUPPLY VOLTAGE

2000

RL = 8Ω

1800

1600

1400

1200

1000

OUPUT POWER (mW)

= 1kHz

f

IN

800

600

400

200

0

2.7 5.5

THD+N = 10%

THD+N = 1%

3.5 4.33.93.1 4.7 5.1
SUPPLY VOTAGE (V)

MAX9879 toc13

MAX9879

Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier

10 ______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VDD= V

PVDDL

= V

PVDDR

= 3.7V, V

CCIO

= 1.8V, V

GND

= V

PGNDL

= V

PGNDR

= 0. Single-ended inputs, preamp = 0dB, volume con-

trols = 0dB, BYPASS = 0, SHDN = 1. Speaker loads connected between OUT_+ and OUT_-. Headphone loads connected from HPL
or HPR to GND. R

SPK

= ∞, RHP= ∞. C1 = C2 = C

BIAS

= 1µF. TA= +25°C, unless otherwise noted.)

SPEAKER AMPLIFIERS (Headphone Disabled)

1000

800

600

400

OUPUT POWER (mW)

200

0

1 100

OUTPUT POWER vs. LOAD

THD+N = 10%

THD+N = 1%

LOAD (Ω)

f = 1kHz

10

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY (SPEAKER MODE)

0

RL = 8Ω

MAX9879 toc14

-10

-20

-30

-40

-50

PSRR (dB)

-60

-70

-80

-90

-100

= 100mV

V

RIPPLE

INPUTS AC GROUNDED

0.01 100110

P-P

RIGHT

LEFT

0.1
FREQUENCY (kHz)

MAX9879 toc15

CROSSTALK vs. FREQUENCY

0

RL = 8Ω

= 1

V

IN

-20

-40

-60

CROSSTALK (dB)

-80

-100

-120

VP-P

RIGHT TO LEFT

LEFT TO RIGHT

0.01 100
FREQUENCY (kHz)

MAX9879 toc16

1010.1

OUTPUT FREQUENCY SPECTRUM

SPEAKER MODE

0

V

= -60dBV

OUT

f = 1kHz

-20
= 8Ω

R

L

UNWEIGHTED

-40

-60

-80

-100

OUTPUT MAGNITUDE (dBV)

-120

-140
02010 15

5

FREQUENCY (kHz)

MAX9879 toc19

MAX9879 toc17

SHDN
1V/div

OUT+ - OUT­1V/div

WIDEBAND FREQUENCY SPECTRUM

(SPEAKER MODE)

0

-10

-20

-30

-40

-50

-60

-70

-80

OUTPUT MAGNITUDE (dBV)

-90

-100

-110

-120
0100110

RBW = 1kHz
INPUT AC GROUNDED

FREQUENCY (MHz)

MAX9879 toc20

MAX9879 toc18

SDA
2V/div

SCL
2V/div

400μs/div

2ms/div