MAXIM MAX9789, MAX9790 Technical data

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-0606; Rev 3; 9/09

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.

General Description

The MAX9789/MAX9790 combine a stereo, 2W Class AB
speaker power amplifier with a stereo 100mW
DirectDrive

®

headphone amplifier in a single device. The
MAX9789/MAX9790 are designed for use with the
Microsoft Windows Vista

®

operating system and are fully
compliant with Microsoft’s Windows Vista specifications.
The headphone amplifier features Maxim’s DirectDrive
architecture that produces a ground-referenced output
from a single supply to eliminate the need for large DC­blocking capacitors, as well as save cost, board space,
and component height. A high +90dB PSRR and low

0.002% THD+N ensures clean, low-distortion amplifica­tion of the audio signal.

Separate speaker and headphone amplifier control
inputs provide independent shutdown of the speaker
and headphone amplifiers, allowing speaker and head­phone amplifiers to be active simultaneously, if
required. The industry-leading click-and-pop suppres­sion circuitry reduces audible transients during startup
and shutdown cycles.

The MAX9789 features an internal LDO that can be used
as a clean power supply for a CODEC or other circuits.
The LDO output voltage is set internally at 4.75V or can
be adjusted between 1.21V and 4.75V using a simple
resistive divider. The LDO is protected against thermal
overloads and short circuits while providing 120mA of
continuous output current and can be enabled indepen­dently of the audio amplifiers.

By disabling the speaker and headphone amplifiers, and
the LDO (for MAX9789), the MAX9789/MAX9790 enter
low-power shutdown mode and draw only 0.3µA.

The MAX9789/MAX9790 operate from a single 4.5V to

5.5V supply and feature thermal-overload and output
short-circuit protection. Devices are specified over the

-40°C to +85°C extended temperature range.

Features

Applications

Note: All devices are specified over the -40°C to +85°C extended
temperature range.

+

Denotes a lead-free/RoHS-compliant package.

*

EP = Exposed pad.

**

Future product—contact factory for availability.

PART

PIN-PACKAGE

INTERNAL LDO

tON (ms)

MAX9789AETJ+

Yes 100

MAX9789BETJ+**

Yes 25

MAX9789CETJ+

Yes 100

MAX9790AETJ+

No 100

MAX9790BETJ+**

No 25

Simplified Block Diagrams

MAX9789

SPKR_EN
HP_EN

MUTE

GAIN1
GAIN2

SPEAKER SUPPLY

4.5V TO 5.5V

HEADPHONE SUPPLY

3.0V TO 5.5V

LDO

4.5V TO 5.5V

SPKR_INR

SPKR_INL

HP_INR

HP_INL

1.21V TO 4.75V

♦ Microsoft Windows Vista Compliant
♦ Class AB 2W Stereo BTL Speaker Amplifier
♦ 100mW DirectDrive Headphone Amplifier

Eliminates Costly, Bulky DC-Blocking Capacitors

♦ Excellent RF Immunity
♦ Integrated 120mA LDO (MAX9789)
♦ High +90dB PSRR, Low 0.002% THD+N
♦ Low-Power Shutdown Mode
♦ Click-and-Pop Suppression
♦ Short-Circuit and Thermal-Overload Protection
♦ Available in 32-Pin Thin QFN (5mm x 5mm x

0.8mm) Package

Notebook Computers

Tablet PCs

Portable Multimedia Players

Windows Vista is a registered trademark of Microsoft Corp.

Pin Configurations appear at end of data sheet.

Simplified Block Diagrams continued at end of data sheet.

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

32 TQFN-EP*

32 TQFN-EP*

32 TQFN-EP*

32 TQFN-EP*

32 TQFN-EP*

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= PVDD= CPVDD= HPVDD= HP_EN = V

LDO_EN

(MAX9789 only) = +5V, V

GND

= V

PGND

= V

CPGND

= SPKR_EN = V

LDO_SET

(MAX9789 only) = 0V, I

LDO_OUT

(MAX9789 only) = 0, C1 = C2 = C

BIAS

= 1µF. RL= ∞, unless otherwise specified, V

GAIN1

= 0,

V

GAIN2

= 5V (A

VSP

= 10dB, A

VHP

= 3.5dB), TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

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.

Supply Voltage (VDD, PVDD, HPVDD,

CPV

DD

to GND)..................................................-0.3V to +6.0V

GND to PGND, CPGND ......................................................±0.3V

CPV

SS

, C1N, VSSto GND......................................-6.0V to +0.3V

HPR, HPL to GND ...............................................................±3.0V

Any Other Pin .............................................-0.3V to (V

DD

+ 0.3V)

Duration of OUT_+, OUT_- Short Circuit

to GND or PV

DD

......................................................Continuous

Duration of Short Circuit between OUT_+, OUT_-

and LDO_OUT.........................................................Continuous

Duration of Short Circuit between HPR, HPL and GND,

V

SS

or HPVDD..........................................................Continuous

Continuous Current (PV

DD

, OUT_+, OUT_-, PGND).............1.7A

Continuous Current (CPV

DD

, C1N, C1P, CPVSS, PVSS,

V

DD,

HPVDD, LDO_OUT, HPR, HPL) .............................850mA

Continuous Input Current (all other pins) .........................±20mA

Continuous Power Dissipation (T

A

= +70°C)
32-Pin Thin QFN Single-Layer Board

(derate 18.6mW/°C above +70°C)..............................1489mW

θ

JA

...........................................................................53.7°C/W

θ

JC

...........................................................................19.9°C/W

32-Pin Thin QFN Multilayer Board

(derate 24.9 mW/°C above +70°C).............................1990mW

θ

JA

...........................................................................40.2°C/W

θ

JC

...........................................................................19.9°C/W

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

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

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

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

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7 using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial

.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

GENERAL

Supply Voltage VDD, PV

Headphone Supply Voltage

Quiescent Current I

Shutdown Current I

Bias Voltage V

Shutdown to Full Operation t

Gain Switching Time t

CPV

HPV

SHDN

DD

DD

DD

DD

BIAS

SON

SW

Channel-to-Channel Gain
Tracking

SPEAKER AMPLIFIER

Output Power P

Total Harmonic Distortion Plus
Noise

OUT

THD+N

,

Guaranteed by PSRR and LDO Line
Regulation Tests

Guaranteed by PSRR Test 3.0 5.5 V

SPKR_EN HP_EN

1 (MAX9789) 0 (MAX9789) 0.1 0.4 mA

1 (MAX9790) 0 (MAX9790) 0.3 6 µA

11 713

0 0 14 29

0 1 18 40

SPKR_EN = VDD, HP_EN = LDO_EN = GND 0.3 6 µA

MAX9789A/MAX9789C/MAX9790A 100

MAX9789B/MAX9790B 25

THD+N = 1%, f = 1kHz,
T

= +25°C

A

RL = 8Ω, P

R

= 4Ω, P

L

4.5 5.5 V

1.7 1.8 1.9 V

10 µs

±0.1 dB

RL = 4Ω 2

R

= 8Ω 1

L

= 1W, f = 1kHz 0.002

OUT

= 1W, f = 1kHz 0.004

OUT

mA

ms

W

%

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= PVDD= CPVDD= HPVDD= HP_EN = V

LDO_EN

(MAX9789 only) = +5V, V

GND

= V

PGND

= V

CPGND

= SPKR_EN = V

LDO_SET

(MAX9789 only) = 0V, I

LDO_OUT

(MAX9789 only) = 0, C1 = C2 = C

BIAS

= 1µF. RL= ∞, unless otherwise specified, V

GAIN1

= 0,

V

GAIN2

= 5V (A

VSP

= 10dB, A

VHP

= 3.5dB), TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Power-Supply Rejection Ratio PSRR

Voltage Gain A

Input Impedance R

Output Offset Voltage V

V

IN

OS

VDD = 4.5V to 5.5V, TA = +25°C 72 90

f = 1kHz, 200mV

P-P

f = 10kHz, 200mV

GAIN1 GAIN2

00 6

01 10

1 0 15.6

1 1 21.6

Measured at speaker amplifier inputs

GAIN1 GAIN2

00 80

01 65

10 45

11 25

Measured between
OUT_+ and OUT_-,
T

= +25°C

A

(Note 4) 70

(Note 4) 50

P-P

MAX9789C ±1 ±25

±1 ±15

dB

dB

kΩ

mV

RL = 8Ω, peak voltage,

Click-and-Pop Level K

A-weighted, 32 samples

CP

per second (Notes 3, 4)

Signal-to-Noise Ratio SNR RL = 8Ω, P

Noise V

Capacitive-Load Drive C

BW = 22Hz to 22kHz 30 µV

n

No sustained oscillations 200 pF

L

L to R, R to L, R

= 70.7nV

Crosstalk

V

OUT

= 1W

OUT

= 8Ω, FS = 0.707V

L

RMS,

Into shutdown -50

Out of shutdown -50

A-weighted 102

f = 22Hz to 22kHz 99

,

RMS

20kHz AES17,

dBV

dB

RMS

-70 dB

BW = 20Hz to 20kHz

Slew Rate SR 1.4 V/µs

HEADPHONE AMPLIFIER

Output Power P

OUT

THD+N = 1%, f =
1kHz, T

= +25°C

A

RL = 32Ω, FS = 0.300V

= 210mV

V

OUT

RMS

RL = 16Ω 100

R

= 32Ω 55

L

,

RMS

, 20kHz AES17,

mW

-77 dB FS

BW = 20Hz to 20kHz

Total Harmonic Distortion Plus
Noise

THD+N

RL = 32Ω, P

RL = 16Ω, P

= 10kΩ, FS = 0.707V

R

L

V

= 500mV

OUT

= 40mW, f = 1kHz 0.02

OUT

= 60mW, f = 1kHz 0.03

OUT

,

RMS

, 20kHz AES17,

RMS

%

-94 dB FS

BW = 20Hz to 20kHz

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VDD= PVDD= CPVDD= HPVDD= HP_EN = V

LDO_EN

(MAX9789 only) = +5V, V

GND

= V

PGND

= V

CPGND

= SPKR_EN = V

LDO_SET

(MAX9789 only) = 0V, I

LDO_OUT

(MAX9789 only) = 0, C1 = C2 = C

BIAS

= 1µF. RL= ∞, unless otherwise specified, V

GAIN1

= 0,

V

GAIN2

= 5V (A

VSP

= 10dB, A

VHP

= 3.5dB), TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Power-Supply Rejection Ratio PSRR

Voltage Gain A

Input Impedance R

Output Offset Voltage V

Click-and-Pop Level K

Dynamic Range DR

V

IN

OS

CP

Signal-to-Noise Ratio SNR

Noise V

Capacitive-Load Drive C

n

L

Crosstalk

Slew Rate SR 0.4 V/µs

Charge-Pump Frequency f

OSC

LOW-DROPOUT LINEAR REGULATOR

Regulator Input Voltage Range V

Ground Current I

Output Current I

DD

GND

OUT

Crosstalk

Fixed Output Voltage Accuracy I

Adjustable Output Voltage Range 1.21 4.75 V

LDO_SET Reference Voltage V

SET

LDO_SET Dual-Mode Threshold 200 mV

HPVDD = 3V to 5.5V, TA = +25°C 70 95

f = 1kHz, V

f = 10kHz, V

RIPPLE

RIPPLE

= 200mV

= 200mV

(Note 4) 84

P-P

(Note 4) 63

P-P

3.5 dB

Measured at headphone amplifier inputs 20 40 80 kΩ

TA = +25°C

RL = 32Ω, peak voltage,

MAX9789C ±2 ±10

Into shutdown -60

±2 ±7

A-weighted, 32 samples
per second (Notes 3, 4)

RL = 32Ω, f = 1kHz, A-weighted,
FS = 0.300V

R

= 10kΩ, f = 1kHz, A-weighted,

L

FS = 0.707V

R

= 32Ω,

L

= 60mW

P

OUT

RMS

RMS

, V

, V

Out of shutdown -60

= 300µV

OUT

OUT

= 707µV

RMS

RMS

22Hz to 22kHz 100

A-weighted 103

89

97

BW = 22Hz to 22kHz 12 µV

No sustained oscillations 200 pF

RL = 32Ω,

L to R, R to L,
20kHz AES17
BW = 20Hz to 20kHz

FS = 0.300V

= 30mV

V

OUT

= 10kΩ,

R

L

FS = 0.707V

= 70.7mV

V

OUT

RMS

RMS

RMS

,

,

RMS

-74

-77

500 550 625

MAX9789C 475 550 625

Inferred from line regulation 4.5 5.5 V

I

= 0mA 0.1 0.4

OUT

I

= 120mA -40

OUT

120 mA

V

= 4.75V, I

OUT

speaker P

= 1mA

OUT

OUT

= 0mA, f = 1kHz,

OUT

= 2W, speaker RL = 4Ω

MAX9789C ±3.0

-95 dB

±1.5

1.18 1.21 1.23

MAX9789C 1.18 1.21 1.25

dB

mV

dBV

dB FS

dB

RMS

dB

kHz

mA

%

V

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

_______________________________________________________________________________________ 5

Note 2: All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Note 3: Specified at room temperature with an 8Ω resistive load connected across BTL output for speaker amplifier. Specified at

room temperature with a 32Ω resistive load connected between HPR, HPL, and GND for headphone amplifier. Speaker and
headphone mode transitions are controlled by SPKR_EN and HP_EN control pins, respectively.

Note 4: Amplifier inputs AC-coupled to GND.
Note 5: Maximum value is due to test limitations.
Note 6: V

LDO_OUT

= V

LDO_OUTNOMINAL

- 2%.

ELECTRICAL CHARACTERISTICS (continued)

(VDD= PVDD= CPVDD= HPVDD= HP_EN = V

LDO_EN

(MAX9789 only) = +5V, V

GND

= V

PGND

= V

CPGND

= SPKR_EN = V

LDO_SET

(MAX9789 only) = 0V, I

LDO_OUT

(MAX9789 only) = 0, C1 = C2 = C

BIAS

= 1µF. RL= ∞, unless otherwise specified, V

GAIN1

= 0,

V

GAIN2

= 5V (A

VSP

= 10dB, A

VHP

= 3.5dB), TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

LDO_SET Input Bias Current
(Note 5)

Dropout Voltage (Note 6) V

Current Limit I

I

SET

LIM

DO

Startup Time 20 µs

Line Regulation

Load Regulation

Ripple Rejection

Output Voltage Noise

DIGITAL INPUTS (SPKR_EN, HP_EN, MUTE, GAIN1, GAIN2, LDO_EN (MAX9789 Only))

Input-Voltage High V

Input-Voltage Low V

INH

INL

Input Bias Current ±1 µA

V

= 4.75V (fixed

OUT

I

output operation),
T

= +25°C

A

V

= 4.5V to 5.5V, LDO_OUT = 2.5V,

IN

I

LDO_OUT

V

LDO_OUT

1mA < I

V

RIPPLE

I

LDO_OUT

20Hz to 22kHz, C
I

LDO_OUT

= 1mA

= 4.75V,

LDO_OUT

= 200mV

= 10mA

= 120mA

< 120mA

P-P

LDO_OUT

I

f = 1kHz 59

f = 10kHz 42

= 2 x 1µF,

±20 ±500 nA

= 50mA 25 50

OUT

= 120mA 75 150

OUT

300 mA

-4.8 +0.8 +4.8 mV/V

0.2 mV/mA

125 µV

2V

0.8 V

mV

dB

RMS

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

6 _______________________________________________________________________________________

Typical Operating Characteristics

(VDD= PVDD= CPVDD= HPVDD= LDO_EN = +5V, V

GND

= V

PGND

= V

CPGND

= V

LDO_SET

= 0V, C1 = C2 = C

BIAS

= CIN= 1µF. RL=

∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A

VSP

= 10dB, A

VHP

= 3.5dB), measurement BW = 20kHz AES17, TA= +25°C,

unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (HEADPHONE MODE)

MAX9789 toc01

FREQUENCY (Hz)

THD+N (dB FS)

10k1k100

-100

-90

-80

-70

-60

-110
10 100k

FS = 0.707V

RMS

V

OUT

= -3dB FS

R

L

= 10k

Ω

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (HEADPHONE MODE)

MAX9789 toc02

FREQUENCY (Hz)

THD+N (dB FS)

10k1k100

-90

-80

-70

-60

-100
10 100k

HPVDD = 3V
FS = 0.707V

RMS

V

OUT

= -3dB FS

R

L

= 10k

Ω

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT VOLTAGE (HEADPHONE MODE)

MAX9789 toc03

OUTPUT VOLTAGE (V

RMS

)

THD+N (%)

1.51.00.5

0.01

0.1

1

10

0.001
0 2.0

RL = 10k

Ω

fIN = 20Hz

fIN = 10kHz

fIN = 1kHz

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT VOLTAGE (HEADPHONE MODE)

MAX9789 toc04

OUTPUT VOLTAGE (V

RMS

)

THD+N (%)

1.51.00.5

0.01

0.1

1

10

0.001
0 2.0

HPVDD = 3V
R

L

= 10k

Ω

fIN = 20Hz

fIN = 1kHz

fIN = 10kHz

CROSSTALK

vs. FREQUENCY (HEADPHONE MODE)

MAX9789 toc05

FREQUENCY (Hz)

CROSSTALK (dB)

10k1k100

-80

-90

-60

-40

-20

-70

-50

-30

-10

0

-100
10 100k

FS = 0.707V

RMS

V

OUT

= -20dB FS

R

L

= 10k

Ω

LEFT TO RIGHT

RIGHT TO LEFT

HEADPHONE OUTPUT SPECTRUM

MAX9789 toc06

FREQUENCY (Hz)

CROSSTALK (dB)

15k10k5k

-80

-90

-60

-40

-20

-70

-50

-30

-10

0

-140

-100

-110

-120

-130

0 20k

FS = 0.300V

RMS

V

OUT

= -60dB FS

R

L

= 10k

Ω

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (SPEAKER MODE)

MAX9789 toc07

FREQUENCY (Hz)

THD+N (dB FS)

1k100

-90

-95

-85

-80

-75

-100
10 100k10k

V

OUT

= -3dB FS

FS = 0.707V

RMS

RL = 3Ω

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (SPEAKER MODE)

MAX9789 toc08

FREQUENCY (Hz)

THD+N (dB FS)

1k100

-90

-95

-85

-80

-75

-100
10 100k10k

V

OUT

= -3dB FS

FS = 0.707V

RMS

RL = 4Ω

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (SPEAKER MODE)

MAX9789 toc09

FREQUENCY (Hz)

THD+N (dB FS)

1k100

-90

-100

-95

-105

-85

-80

-75

-110
10 100k10k

V

OUT

= -3dB FS

FS = 0.707V

RMS

RL = 8Ω

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

_______________________________________________________________________________________

7

Typical Operating Characteristics (continued)

(VDD= PVDD= CPVDD= HPVDD= LDO_EN = +5V, V

GND

= V

PGND

= V

CPGND

= V

LDO_SET

= 0V, C1 = C2 = C

BIAS

= CIN= 1µF. RL=

∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A

VSP

= 10dB, A

VHP

= 3.5dB), measurement BW = 20kHz AES17, TA= +25°C,

unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT POWER (SPEAKER MODE)

MAX9789 toc10

OUTPUT POWER (W)

THD+N (%)

1.51.00.5

0.01

0.1

1

10

0.001
0 3.02.0 2.5

RL = 3

Ω

fIN = 10kHz

fIN = 20Hz

fIN = 1kHz

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT POWER (SPEAKER MODE)

MAX9789 toc11

OUTPUT POWER (W)

THD+N (%)

1.51.00.5

0.01

0.1

1

10

0.001
0 2.52.0

RL = 4

Ω

fIN = 10kHz

fIN = 20Hz

fIN = 1kHz

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT POWER (SPEAKER MODE)

MAX9789 toc12

OUTPUT POWER (W)

THD+N (%)

1.00.5

0.01

0.1

1

10

0.001

01.5

RL = 8

Ω

fIN = 10kHz

fIN = 20Hz

fIN = 1kHz

CROSSTALK

vs. FREQUENCY (SPEAKER MODE)

MAX9789 toc13

FREQUENCY (Hz)

CROSSTALK (dB)

10k1k100

-80

-60

-40

-20

0

-100

-70

-50

-30

-10

-90

10 100k

FS = 0.707V

RMS

V

OUT

= -20dB FS

R

L

= 8

Ω

LEFT TO RIGHT

RIGHT TO LEFT

SPEAKER OUTPUT SPECTRUM

FREQUENCY (Hz)

CROSSTALK (dB)

MAX9789 toc14

0 5k 10k 15k 20k

-140

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

FS = 0.707V

RMS

V

OUT

= -60dB FS

R

L

= 8Ω

OUTPUT POWER vs. LOAD RESISTANCE

(SPEAKER MODE)

RL (Ω)

OUTPUT POWER (W)

MAX9789 toc15

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1 10 100

fIN = 1kHz

THD+N = 1%

THD+N = 10%

POWER DISSIPATION PER CHANNEL

vs. OUTPUT POWER (SPEAKER MODE)

OUTPUT POWER PER CHANNEL (W)

POWER DISSIPATION PER CHANNEL (W)

MAX9789 toc16

0 0.5 1.0 1.5 2.0

0

0.25

0.50

0.75

1.00

1.25

1.50

RL = 8Ω

RL = 4Ω

fIN = 1kHz

POWER-SUPPLY REJECTION RATIO

(SPEAKER MODE)

FREQUENCY (Hz)

PSRR (dB)

MAX9789 toc17

10 100 1k 10k 100k

100

-90

-70

-80

-40

-50

-60

-30

-20

-10

0

V

RIPPLE

= 200mV

P-P

OUTPUT REFERRED

SPEAKER SHUTDOWN WAVEFORM

MAX9789 toc20

20ms/div

2V/div

5V/div

100mV/div

OUT_+ AND OUT_-

OUT_+ - OUT_-

SPKR_EN

Typical Operating Characteristics (continued)

(VDD= PVDD= CPVDD= HPVDD= LDO_EN = +5V, V

GND

= V

PGND

= V

CPGND

= V

LDO_SET

= 0V, C1 = C2 = C

BIAS

= CIN= 1µF. RL=

∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A

VSP

= 10dB, A

VHP

= 3.5dB), measurement BW = 20kHz AES17, TA= +25°C,

unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

8 _______________________________________________________________________________________

SPEAKER STARTUP WAVEFORM

MAX9789A/MAX9789C/MAX9790A

MAX9789 toc18

SPKR_EN
5V/div

OUT_+ AND OUT_­2V/div

SPEAKER STARTUP WAVEFORM

MAX9789B/MAX9790B

MAX9789 toc19

SPKR_EN
5V/div

OUT_+ AND OUT_­2V/div

20ms/div

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (HEADPHONE MODE)

-65

-70

-75

V

= -3dB FS

-80

-85

-90

THD+N (dB FS)

-95

-100

-105

-110

OUT

HPVDD = 3V
FS = 0.300V
RL = 32Ω

10 100k

RMS

FREQUENCY (Hz)

10k1k100

MAX9789 toc22

OUT_+ - OUT_­100mV/div

TOTAL HARMONIC DISTORTION PLUS NOISE

-65

-70

-75

-80

-85

-90

THD+N (dB FS)

-95

-100

-105

-110
10 100k

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (HEADPHONE MODE)

-65

-70

-75

V

= -3dB FS

OUT

-80

-85

-90

THD+N (dB FS)

-95

-100

FS = 0.300V

-105

-110
10 100k

RL = 16Ω

RMS

10k1k100

FREQUENCY (Hz)

20ms/div

vs. FREQUENCY (HEADPHONE MODE)

V

= -3dB FS

OUT

FS = 0.300V

RMS

Ω

RL = 32

10k1k100

FREQUENCY (Hz)

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. FREQUENCY (HEADPHONE MODE)

-65

-70

MAX9789 toc23

-75

V

= -3dB FS

OUT

-80

-85

-90

THD+N (dB FS)

-95

-100

HPVDD = 3V
FS = 0.300V

-105

-110

10 100k

RL = 16Ω

RMS

OUT_+ - OUT_­100mV/div

MAX9789 toc21

FREQUENCY (Hz)

MAX9789 toc24

10k1k100

MAX9789/MAX9790

HEADPHONE OUTPUT SPECTRUM

MAX9789 toc30

FREQUENCY (kHz)

AMPLITUDE (dB)

15105

-80

-60

-40

-20

0

-140

-70

-50

-30

-10

-100

-120

-90

-110

-130

020

FS = 0.707V

RMS

V

OUT

= -60dB FS

R

L

= 32

Ω

OUTPUT POWER vs. LOAD RESISTANCE

(HEADPHONE MODE)

RL (Ω)

OUTPUT POWER (mW)

MAX9789 toc31

0

50

100

150

10 100 1000

THD+N = 1%

THD+N = 10%

fIN = 1kHz

OUTPUT POWER vs. LOAD RESISTANCE

(HEADPHONE MODE)

RL (Ω)

OUTPUT POWER (mW)

MAX9789 toc32

0

50

100

10 100 1000

HPVDD = 3V
f

IN

= 1kHz

THD+N = 1%

THD+N = 10%

Typical Operating Characteristics (continued)

(VDD= PVDD= CPVDD= HPVDD= LDO_EN = +5V, V

GND

= V

PGND

= V

CPGND

= V

LDO_SET

= 0V, C1 = C2 = C

BIAS

= CIN= 1µF. RL=

∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A

VSP

= 10dB, A

VHP

= 3.5dB), measurement BW = 20kHz AES17, TA= +25°C,

unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT POWER (HEADPHONE MODE)

MAX9789 toc26

OUTPUT POWER (mW)

THD+N (%)

604020

0.1

10

0.01

1

010080

RL = 32

Ω

f = 1kHz

f = 10kHz

f = 20Hz

CROSSTALK

vs. FREQUENCY (HEADPHONE MODE)

MAX9789 toc29

FREQUENCY (Hz)

CROSSTALK (dB)

10k1k100

-80

-60

-40

-20

0

-110

-70

-50

-30

-10

-90

-100

10 100k

FS = 0.300V

RMS

V

OUT

= -20dB FS

R

L

= 32

Ω

LEFT TO RIGHT

RIGHT TO LEFT

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

_______________________________________________________________________________________

9

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT POWER (HEADPHONE MODE)

10

MAX9789 toc25

1

THD+N (%)

0.1

0.01

f = 20Hz

f = 1kHz

0200

OUTPUT POWER (mW)

f = 10kHz

15010050

RL = 16

Ω

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT POWER (HEADPHONE MODE)

10

MAX9789 toc28

1

THD+N (%)

0.1

f = 20Hz

f = 1kHz

f = 10kHz

TOTAL HARMONIC DISTORTION PLUS NOISE

vs. OUTPUT POWER (HEADPHONE MODE)

10

1

f = 20Hz

THD+N (%)

0.1

0.01
0150

OUTPUT POWER (mW)

f = 10kHz

f = 1kHz

HPVDD = 3V

Ω

= 16

R

L

10050

MAX9789 toc27

HPVDD = 3V

Ω

= 32

R

0.01
010080

OUTPUT POWER (mW)

604020

L

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

10 ______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VDD= PVDD= CPVDD= HPVDD= LDO_EN = +5V, V

GND

= V

PGND

= V

CPGND

= V

LDO_SET

= 0V, C1 = C2 = C

BIAS

= CIN= 1µF. RL=

∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A

VSP

= 10dB, A

VHP

= 3.5dB), measurement BW = 20kHz AES17, TA= +25°C,

unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)

POWER DISSIPATION vs. OUTPUT POWER

(HEADPHONE MODE)

300
275
250
225
200
175
150
125
100

75
50

POWER DISSIPATION PER CHANNEL (mW)

25

0

0 25 50 75 100 125

OUTPUT POWER PER CHANNEL (mW)

RL = 16Ω

RL = 32Ω

HEADPHONE OUTPUT POWER vs. HPV

125

100

75

50

25

HEADPHONE OUTPUT POWER (mW)

THD+N = 1%
f

= 1kHz

IN

0

3.0 3.5 4.0 4.5 5.0

RL = 16Ω

HPV

(V)

DD

RL = 32Ω

MAX9789 toc33

DD

MAX9789 toc35

POWER DISSIPATION PER CHANNEL

vs. OUTPUT POWER (HEADPHONE MODE)

125

HPVDD = 3V

100

75

50

25

POWER DISSIPATION PER CHANNEL (mW)

0

0 20406080

OUTPUT POWER PER CHANNEL (mW)

RL = 16Ω

RL = 32Ω

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY (HEADPHONE MODE)

0

V

= 200mV

RIPPLE

-10
OUTPUT REFERRED

-20

-30

-40

-50

PSRR (dB)

-60

-70

-80

-90

-100
10 100 1k 10k 100k

P-P

FREQUENCY (Hz)

MAX9789 toc34

MAX9789 toc36

HEADPHONE STARTUP WAVEFORM

MAX9789A/MAX9789C/MAX9790A

20ms/div

MAX9789 toc37

HP_EN
5V/div

HP_
500mV/div

HEADPHONE STARTUP WAVEFORM

MAX9789B/MAX9790B

20ms/div

MAX9789 toc38

HP_EN
5V/div

HP_
500mV/div

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________

11

Typical Operating Characteristics (continued)

(VDD= PVDD= CPVDD= HPVDD= LDO_EN = +5V, V

GND

= V

PGND

= V

CPGND

= V

LDO_SET

= 0V, C1 = C2 = C

BIAS

= CIN= 1µF. RL=

∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A

VSP

= 10dB, A

VHP

= 3.5dB), measurement BW = 20kHz AES17, TA= +25°C,

unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)

HEADPHONE SHUTDOWN WAVEFORM

MAX9789 toc39

20ms/div

HP_

HP_EN

5V/div

500mV/div

SUPPLY CURRENT vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

MAX9789 toc40

4.50 4.75 5.00 5.25 5.50

-5

0

5

10

15

20

SPKR_EN = 0

HP_EN = 0

SPKR_EN = 0

HP_EN = 1

SPKR_EN = 1

HP_EN = 0

SPKR_EN = 1

HP_EN = 1

SHUTDOWN CURRENT vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

SHUTDOWN CURRENT (μA)

MAX9789 toc41

4.50 4.75 5.00 5.25 5.50

0

0.1

0.2

0.3
SPKR_EN = 5V
HP_EN = 0
LDO_EN = 0 (MAX9789)

LDO OUTPUT VOLTAGE ACCURACY

vs. I

LOAD

I

LOAD

(mA)

LDO OUTPUT VOLTAGE ACCURACY (%)

MAX9789 toc42

0 25 50 75 100 125 150

-2.0

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0
V

LDO_OUT

= 4.75V

LDO OUTPUT VOLTAGE ACCURACY

vs. AMPLIFIER OUTPUT POWER

AMPLIFIER OUTPUT POWER (W)

LDO OUTPUT VOLTAGE ACCURACY (%)

MAX9789 toc43

0 0.5 1.0 1.5 2.0 2.5 3.0

-0.10

-0.05

0

0.05

0.10
V

LDO_OUT

= 4.75V

I

LDO_OUT

= 0A

LDO OUTPUT VOLTAGE ACCURACY

vs. TEMPERATURE

TEMPERATURE (°C)

LDO OUTPUT VOLTAGE ACCURACY (%)

MAX9789 toc44

-40 -15 10 35 60 85

-2.0

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0
I

LDO_OUT

= 1mA

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

12 ______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VDD= PVDD= CPVDD= HPVDD= LDO_EN = +5V, V

GND

= V

PGND

= V

CPGND

= V

LDO_SET

= 0V, C1 = C2 = C

BIAS

= CIN= 1µF. RL=

∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A

VSP

= 10dB, A

VHP

= 3.5dB), measurement BW = 20kHz AES17, TA= +25°C,

unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)

DROPOUT VOLTAGE vs. I

LOAD

MAX9789 toc45

I

LOAD

(mA)

DROPOUT VOLTAGE (mV)

125100755025

10

20

30

40

50

60

70

80

90

100

0

0150

V

LDO_OUT

= 4.75V

V

LDO_OUT

= 3.3V

RIPPLE REJECTION vs. FREQUENCY

MAX9789 toc46

FREQUENCY (Hz)

RIPPLE REJECTION (dB)

10k1k100

-80

-70

-60

-50

-40

-30

-20

-10

0

-90
10 100k

V

LDO_OUT

= 4.75V

V

RIPPLE

= 200mV

P-P

I

OUT

= 10mA

OUTPUT REFERRED

V

LDO_OUT

= 3.3V

OUTPUT NOISE vs. FREQUENCY

MAX9789 toc47

FREQUENCY (Hz)

OUTPUT NOISE (μV√Hz)

10k1k100

0.1

1

10

0.01
10 100k

LINE-TRANSIENT RESPONSE

1ms/div

LDO SHUTDOWN RESPONSE

200ms/div

I

LOAD

MAX9789 toc48

MAX9789 toc50

= 0mA

V
1V/div

5.5V

4.5V

LDO_OUT
(AC-COUPLED)
20mV/div

LDO_EN
2V/div

V
2V/div

DD

LDO_OUT

LDO LOAD-TRANSIENT RESPONSE

20ms/div

LDO CROSSTALK vs. FREQUENCY

-20

-30

-40

-50

-60

-70
RIGHT SPEAKER TO LDO

-80

CROSSTALK (dB)

-90

-100

-110

-120

LEFT SPEAKER TO LDO

10 100 1k 10k 100k

FREQUENCY (Hz)

V

LDO_OUT

P

OUT

= 4Ω

R

L

I

OUT

= 2W

= 0mA

MAX9789 toc49

= 4.75V

I

LDO_OUT

15mA/div

AC-COUPLED
V

LDO_OUT

10mV/div

MAX9789 toc51

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 13

Pin Description

PIN

MAX9789 MAX9790

1 — LDO_SET

2 2 SPKR_INR Right-Channel Speaker Amplifier Input

3 3 SPKR_INL Left-Channel Speaker Amplifier Input

4 — LDO_EN LDO Enable. Connect LDO_EN to VDD to enable the LDO.

5, 21 5, 21 PGND Power Ground. Star-connect to GND.

6 6 OUTL+ Left-Channel Speaker Amplifier Output, Positive Phase

7 7 OUTL- Left-Channel Speaker Amplifier Output, Negative Phase

8, 18 8, 18 PV

9 9 CPV

10 10 C1P

11 11 CPGND Charge-Pump Ground. Connect directly to PGND plane.

12 12 C1N

13 13 CPV

14 14 PV

15 15 HPR Right-Channel Headphone Amplifier Output

16 16 HPL Left-Channel Headphone Amplifier Output

17 17 HPV

19 19 OUTR- Right-Channel Speaker Amplifier Output, Negative Phase

20 20 OUTR+ Right-Channel Speaker Amplifier Output, Positive Phase

22 22 HP_EN Active-High Headphone Amplifier Enable
23 23 SPKR_EN Active-Low Speaker Amplifier Enable

24 24 BIAS Common-Mode Bias Voltage. Bypass with a 1µF capacitor to GND.
25 25 MUTE Active-Low Mute Enable. Mutes speaker and headphone amplifiers.

26 26 HP_INR Right-Channel Headphone Amplifier Input

27 27 HP_INL Left-Channel Headphone Amplifier Input

28 4, 28 GND Signal Ground. Star-connect to PGND.

29 — LDO_OUT LDO Output. Bypass with two 1µF capacitors to GND.

30 30 V

31 31 GAIN1 Speaker Amplifier Gain Select 1

32 32 GAIN2 Speaker Amplifier Gain Select 2

— 1, 29 N.C. No Connection. Not internally connected.

EP EP EP Exposed Paddle. Connect to GND.

NAME FUNCTION

Regulator Feedback Input. Connect to GND for 4.75V fixed output. Connect to a resistor­divider for adjustable output. See Figure 1.

Speaker Amplifier Power-Supply Input. Bypass with a 0.1µF capacitor to PGND.

DD

Charge-Pump Power Supply. Connect a 1µF capacitor between CPVDD and PGND.

DD

Charge-Pump Flying Capacitor Positive Terminal. Connect a 1µF capacitor between C1P
to C1N.

Charge-Pump Flying Capacitor Negative Terminal. Connect a 1µF capacitor between C1P
to C1N.

Charge-Pump Output. Connect to PVSS.

SS

Headphone Amplifier Negative Power Supply. Connect a 1µF capacitor between PVSS and

SS

PGND.

Headphone Amplifier Positive Power Supply. Connect a 10µF capacitor between HPV

DD

and PGND.

Positive Power Supply and LDO Input (MAX9789). Bypass with one 0.1µF capacitor and

DD

two 1µF capacitors to GND (MAX9789). Bypass with one 0.1µF capacitor and one 1µF
capacitor to GND (MAX9790).

DD

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

14 ______________________________________________________________________________________

Detailed Description

The MAX9789/MAX9790 combine a 2W BTL speaker
amplifier with an 100mW DirectDrive headphone amplifi­er. These devices feature comprehensive click-and-pop
suppression and programmable four-level speaker ampli­fier gain control. The MAX9789/MAX9790 feature high
+90dB PSRR, low 0.002% THD+N, industry-leading click­and-pop performance, low-power shutdown mode, and
excellent RF immunity. The MAX9789 incorporates an
integrated LDO that serves as a clean power supply for a
CODEC or other circuits.

The MAX9789/MAX9790 is Microsoft Windows Vista com­pliant. See Table 1 for a comparison of the Microsoft
Windows Vista premium mobile specifications and
MAX9789/MAX9790 specifications.

The speaker amplifiers use BTL architecture, doubling the
voltage drive to the speakers and eliminating the need for
DC-blocking capacitors. The output consists of two sig­nals, identical in magnitude, but 180° out of phase.

The headphone amplifiers use Maxim’s DirectDrive
architecture to eliminate the bulky output DC-blocking
capacitors required by traditional headphone ampli­fiers. A charge pump inverts a positive supply (CPVDD)
to create a negative supply (CPV

SS

). The headphone
amplifiers operate from these bipolar supplies with their
outputs biased about GND. The benefit of the GND
bias is that the amplifier outputs no longer have a DC
component (typically V

DD

/ 2). This feature eliminates

the large DC-blocking capacitors required with conven-

tional headphone amplifiers to conserve board space
and system cost, as well as improve low-frequency
response.

The MAX9789/MAX9790 feature programmable speak­er amplifier gain, allowing the speaker gain to be set by
the logic voltages applied to GAIN1 and GAIN2, while
the headphone amplifiers feature a fixed 3.5dB gain.
Both amplifiers feature an undervoltage lockout that
prevents operation from an insufficient power supply
and click-and-pop suppression that eliminates audible
transients on startup and shutdown. The amplifiers
include thermal overload and short-circuit protection.
An additional feature of the speaker amplifiers is that
there is no phase inversion from input to output.

Low-Dropout Linear Regulator

(MAX9789 Only)

The MAX9789’s low-dropout (LDO) linear regulator can
be used to provide a clean power supply to a CODEC
or other circuitry. The LDO can be enabled indepen­dently of the audio amplifiers. Set LDO_EN = VDDto
enable the LDO or set LDO_EN = GND to disable the
LDO. The LDO is capable of providing up to 120mA
continuous current and features Maxim’s Dual Mode™
feedback, easily enabling a fixed 4.75V output or a
user-adjustable output. When LDO_SET is connected
to GND, the output is internally set to 4.75V. The output
voltage can be adjusted from 1.21V to 4.75V by con­necting two external resistors as a voltage divider, at
LDO_SET (Figure 1).

Note: THD+N, DYNAMIC RANGE, and CROSSTALK should be measured in accordance with AES-17 audio measurements standards.

Table 1. Windows Premium Mobile Vista Specifications vs. MAX9789/MAX9790
Specifications

DEVICE TYPE REQUIREMENT

WINDOWS PREMIUM MOBILE Vista

SPECIFICATIONS

MAX9789/MAX9790

TYPICAL PERFORMANCE

THD+N

≤ -65dB FS

[20Hz, 20kHz]

-94dB FS

[20Hz, 20kHz]

Dynamic range with
signal present

≤ -80dB FS,
A-weighted

-97dB FS,

A-weighted

Analog Line Output
Jack (R

L

= 10kΩ,

FS = 0.707V

RMS

)

≤ -50dB

[20Hz, 20kHz]

-77dB

[20Hz, 20kHz]

THD+N

≤ -45dB FS

[20Hz, 20kHz]

-77dB FS

[20Hz, 20kHz]

Dynamic range with
signal present

≤ -60dB FS,
A-weighted

-89dB FS,

A-weighted

Analog Headphone
Out Jack (R

L

= 32Ω,

FS = 0.300V

RMS

)

Headphone output
crosstalk

≤ -50dB

[20Hz, 20kHz]

-74dB

[20Hz, 20kHz]

Dual Mode is a trademark of Maxim Integrated Products, Inc.

Line output crosstalk

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 15

The output voltage is set by the following equation:

where V

LDO_SET

= 1.21V.

To simplify resistor selection:

Since the input bias current at LDO_SET is typically
less than 500nA (max), large resistance values can be
used for R1 and R2 to minimize power consumption
without compromising accuracy. The parallel combina­tion of R1 and R2 should be less than 1MΩ.

DirectDrive

Conventional single-supply headphone amplifiers have
their outputs biased about a nominal DC voltage
(V

DD

/ 2) for maximum dynamic range. Large coupling
capacitors are needed to block this DC bias from the
headphones. Without these capacitors, a significant
amount of DC current flows to the headphone, resulting
in unnecessary power dissipation and possible dam­age to both headphone and headphone amplifier.

Maxim’s DirectDrive architecture uses a charge pump
to create an internal negative supply voltage. It allows
the MAX9789/MAX9790 headphone amplifier output to
be biased about GND. With no DC component, there is
no need for the large DC-blocking capacitors. Instead

of two large capacitors (330µF typically required to
meet Vista magnitude response specifications), the
MAX9789/MAX9790 charge pump requires only two
small 1µF ceramic capacitors, conserving board
space, reducing cost, and improving the low-frequency
response of the headphone amplifier.

Previous attempts to eliminate the output coupling
capacitors involved biasing the headphone return
(sleeve) to the DC bias voltage of the headphone
amplifiers. This method raised some issues:

• The sleeve is typically grounded to the chassis.
Using this biasing approach, the sleeve must be iso­lated from system ground, complicating product
design.

• During an ESD strike, the amplifier’s ESD structures
are the only path to system ground. The amplifier
must be able to withstand the full ESD strike.

• When using the headphone jack as a line out to
other equipment, the bias voltage on the sleeve may
conflict with the ground potential from other equip­ment, resulting in large ground loop current and
possible damage to the amplifiers.

Low-Frequency Response

In addition to the cost and size disadvantages, the DC­blocking capacitors limit the low-frequency response of
the amplifier and distort the audio signal:

• The impedance of the headphone load and the DC­blocking capacitor form a highpass filter with the

-3dB point determined by:

where RLis the impedance of the headphone and
C

OUT

is the value of the DC-blocking capacitor.

• The highpass filter is required by conventional single­ended, single-supply headphone amplifier to block
the midrail DC component of the audio signal from the
headphones. Depending on the -3dB point, the filter
can attenuate low-frequency signals within the audio
band. Larger values of C

OUT

reduce the attenuation,
but are physically larger, more expensive capacitors.
Figure 2 shows the relationship between the size of
C

OUT

and the resulting low-frequency attenuation.
Note the Vista’s magnitude response specification
calls for a -3dB point at 20Hz at the headphone jack.
The -3dB point at 20Hz for a 32Ω headphone requires
a 330µF blocking capacitor (Table 2).

f

RC

dB

L OUT

− =

3

1

2π

RR

V

LDO OUT

12

121

1=

⎛
⎝

⎜

⎞
⎠

⎟

−

_

.

VV

R
R

LDO OUT LDO SET__

=+

⎛
⎝

⎜

⎞
⎠

⎟

1

1

2

MAX9789

LDO_OUT

LDO_SET

GND

1μF

R1

R2

1μF

TO HDA
CODEC

Figure 1. Adjustable Output Using External Feedback
Resistors.

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

16 ______________________________________________________________________________________

• The voltage coefficient of the capacitor, the change
in capacitance due to a change in the voltage
across the capacitor, distorts the audio signal. At
frequencies around the -3dB point, this effect is
maximized and the voltage coefficient appears as
frequency-dependent distortion. Figure 3 shows the
THD+N introduced by two different capacitor
dielectrics. Note that around the -3dB point, THD+N
increases dramatically.

• The combination of low-frequency attenuation and fre­quency-dependent distortion compromises audio
reproduction. DirectDrive improves low-frequency
reproduction in portable audio equipment that empha­sizes low-frequency effects, such as multimedia lap­tops, MP3, CD, and DVD players (See Table 2).

Charge Pump

The MAX9789/MAX9790 feature a low-noise charge
pump. The 550kHz switching frequency is well beyond
the audio range, and does not interfere with the audio
signals. The switch drivers feature a controlled switching

speed that minimizes noise generated by switching
transients. Limiting the switching speed of the charge
pump minimizes the di/dt noise caused by the parasitic
bond wire and trace inductance.

BIAS

The MAX9789/MAX9790 feature an internally generat­ed, power-supply independent, common-mode bias
voltage of 1.8V referenced to GND. BIAS provides both
click-and-pop suppression and sets the DC bias level
for the amplifiers. The BIAS pin should be bypassed to
GND with a 1µF capacitor. No external load should be
applied to BIAS. Any load lowers the BIAS voltage,
affecting the overall performance of the device.

Headphone and Speaker Amplifier Gain

The MAX9789/MAX9790 feature programmable speak­er amplifier gain, set by the logic voltages applied to
pins GAIN1 and GAIN2. Table 3 shows the logic com­binations that can be applied to pins GAIN1 and GAIN2
and their affects on the speaker amplifier gain. The
headphone amplifier gain is fixed at 3.5dB.

Figure 2. Low-Frequency Attenuation of Common DC-Blocking
Capacitor Values

Figure 3. Distortion Contributed by DC-Blocking Capacitors

Table 3. MAX9789/MAX9790
Programmable Gain Settings

Table 2. Low-Frequency Rolloff

*Vista requirement for 32Ωload.

LOW-FREQUENCY ROLLOFF

0

-3

-6

-9

-12

-15

-18

ATTENUATION (dB)

-21

-24

-27

-30
1 10 100 1k 10k 100k

= 16Ω)

(R

L

DirectDrive

330μF

220μF

100μF

33μF

FREQUENCY (Hz)

f

(Hz)

C

(µF)

OUT

22 452 226

33 301 151

100 99 50

220 45 23

330* 30 15

470 21 11

R

= 16Ω RL = 32Ω

L

-3dB

ADDITIONAL THD+N DUE TO

10

0.1

THD+N (%)

0.01

0.001

0.0001

DC-BLOCKING CAPACITORS

C

= 100μF

OUT

Ω

= 16

R

1

TANTALUM

ALUM/ELEC

10 100k

FREQUENCY (Hz)

L

10k1k100

MAX9789/MAX9790

GAIN1 GAIN2

0 0 6 3.5

0 1 10 3.5

1 0 15.6 3.5

1 1 21.6 3.5

SPEAKER MODE

GAIN (dB)

HEADPHONE

MODE GAIN (dB)

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 17

Speaker and Headphone

Amplifier Enable

The MAX9789/MAX9790 feature control inputs for the
independent enabling of the speaker and headphone
amplifiers, allowing both to be active simultaneously if
required. Driving SPKR_EN high disables the speaker
amplifiers. Driving HP_EN low independently disables
the headphone amplifiers. For applications that require
only one of the amplifiers to be on at a given time,
SPKR_EN and HP_EN can be tied together allowing a
single logic voltage to enable either the speaker or the
headphone amplifier as shown in Figure 4.

MUTE

The MAX9789/MAX9790 allow for the speaker and
headphone amplifiers to be muted. By driving MUTE
low, both the speaker and headphone amplifiers are
muted. When muted, the speaker outputs remain
biased at V

DD

/ 2.

Shutdown

The MAX9789/MAX9790 feature a low-power shutdown
mode, drawing 0.3µA of supply current. By disabling the
speaker, headphone amplifiers and the LDO (for
MAX9789), the MAX9789/MAX9790 enter low-power
shutdown mode. Set SPKR_EN to VDDand HP_EN and
LDO_EN to GND to disable the speaker amplifiers, head­phone amplifiers, and LDO, respectively.

Click-and-Pop Suppression

Speaker Amplifier

The MAX9789/MAX9790 speaker amplifiers feature
Maxim’s comprehensive, industry-leading click-and­pop suppression. During startup, the click-and-pop
suppression circuitry eliminates any audible transient
sources internal to the device. When entering shut­down, the differential speaker outputs ramp to GND
quickly and simultaneously.

Headphone Amplifier

In conventional single-supply headphone amplifiers, the
output-coupling capacitor is a major contributor of audi­ble clicks and pops. Upon startup, the amplifier charges
the coupling capacitor to its bias voltage, typically
V

DD

/ 2. Likewise, during shutdown, the capacitor is dis­charged to GND. A DC shift across the capacitor results,
which in turn, appears as an audible transient at the
headphone. Since the MAX9789/MAX9790 do not require
output-coupling capacitors, no audible transient occurs.

Additionally, the MAX9789/MAX9790 features extensive
click-and-pop suppression that eliminates any audible
transient sources internal to the device. The
startup/shutdown waveform in the

Typical Operating

Characteristics

shows that there are minimal spectral

components in the audible range at the output.

Applications Information

BTL Speaker Amplifiers

The MAX9789/MAX9790 feature speaker amplifiers
designed to drive a load differentially, a configuration
referred to as bridge-tied load (BTL). The BTL configu­ration (Figure 5) offers advantages over the single­ended configuration, where one side of the load is
connected to ground. Driving the load differentially
doubles the output voltage compared to a single­ended amplifier operating under similar conditions. The
doubling of the output voltage yields four times the out­put power at the load.

Since the differential outputs are biased at mid-supply,
there is no net DC voltage across the load. This elimi­nates the need for DC-blocking capacitors required for
single-ended amplifiers. These capacitors can be
large, expensive, consume board space, and degrade
low-frequency performance.

Figure 4. Enabling Either the Speaker or Headphone Amplifier
with a Single Control Pin

Figure 5. Bridge-Tied Load Configuration

MAX9789/MAX9790

SINGLE

CONTROL PIN

SPKR_EN

HP_EN

+1

-1

V

OUT(P-P)

2 x V

V

OUT(P-P)

OUT(P-P)

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

18 ______________________________________________________________________________________

Mono Speaker Configuration

The MAX9789 stereo BTL Class AB speaker amplifier
can be configured to drive a mono speaker. Rather
than combining the CODEC’s left- and right-input sig­nals in a resistive network prior to one channel of the
speaker amplifier input, the transducer itself can be
connected to the BTL speaker amplifier output as
shown in Figure 6. When compared to the resistive net­work implementation, the configuration in Figure 6 will:

1) Eliminate noise pickup by eliminating the high­impedance node at the CODEC’s left- and right­signal mixing point. SNR performance will be
improved as a result.

2) Eliminate gain error by eliminating any resistive
mismatch between the external resistance used to
sum the left and right signals and the MAX9789
internal resistance.

Power Dissipation and Heat Sinking

Under normal operating conditions, the MAX9789/
MAX9790 can dissipate a significant amount of power.
The maximum power dissipation for each package is
given in the

Absolute Maximum Ratings

section under
Continuous Power Dissipation, or can be calculated by
the following equation:

where T

J(MAX)

is +150°C, TAis the ambient tempera-

ture, and θJAis the reciprocal of the derating factor in
°C/W as specified in the

Absolute Maximum Ratings

section. For example, θJAfor the 32-pin TQFN-EP pack­age is +40.2°C/W for a multilayer PC board.

Output Power (Speaker Amplifier)

The increase in power delivered by the BTL configura­tion directly results in an increase in internal power dis­sipation over the single-ended configuration. The
maximum power dissipation for a given V

DD

and load is

given by the following equation:

If the power dissipation for a given application exceeds
the maximum allowed for a given package, either reduce
VDD, increase load impedance, decrease the ambient
temperature, or add heat sinking to the device. Large
output, supply, and ground PC board traces improve the
maximum power dissipation in the package.

Thermal-overload protection limits total power dissipa­tion in these devices. When the junction temperature
exceeds +150°C, the thermal-protection circuitry dis­ables the amplifier output stage. The amplifiers are
enabled once the junction temperature cools by +15°C.
This results in a pulsing output under continuous ther­mal-overload conditions as the device heats and cools.

Power Supplies

The MAX9789/MAX9790 have separate supply pins for
each portion of the device, allowing for the optimum
combination of headroom and power dissipation and
noise immunity. The speaker amplifiers are powered
from PVDD. PVDDranges from 4.5V to 5.5V. The head­phone amplifiers are powered from HPVDDand PVSS.
HPVDDis the positive supply of the headphone ampli­fiers and ranges from 3V to 5.5V. PV

SS

is the negative

supply of the headphone amplifiers. Connect PV

SS

to
CPVSS. The charge pump is powered by CPVDD.
CPVDDranges from 3V to 5.5V and should be the same
potential as HPVDD. The charge pump inverts the volt­age at CPVDD, and the resulting voltage appears at
CPVSS. The internal LDO and the remainder of the
device is powered by VDD.

Component Selection

Supply Bypassing

The MAX9789/MAX9790 have separate supply pins for
each portion of the device, allowing for the optimum
combination of headroom and power dissipation and
noise immunity.

Speaker Amplifier Power-Supply Input (PVDD)

The speaker amplifiers are powered from PVDD. PV

DD

ranges from 4.5V to 5.5V. Bypass PVDDwith a 0.1µF
capacitor to PGND. Note additional bulk capacitance is
required at the device if long input traces between
PVDDand the power source are used.

P

V

R

DISS MAX

DD

L

()

=

2

2

2

π

P

TT

DISSPKG MAX

J MAX A

JA

()

()

=

−

θ

Figure 6. Mono Signal Output Configuration for MAX9789

C

CODEC

SPKR_OUTL

SPKR_OUTR

LINE_OUTR

LINE_OUTL

IN1

SPKR_INL

C

IN1

SPKR_INR

C

IN2

HP_INL

C

IN2

HP_INR

OUTL+

OUTL-

MAX9789

OUTR+

OUTR-

HPL

HPR

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 19

Headphone Amplifier Power-Supply

Input (HPV

DD

and PVSS)

The headphone amplifiers are powered from HPV

DD

and PVSS. HPVDDis the positive supply of the head­phone amplifiers and ranges from 3.0V to 5.5V. Bypass
HPV

DD

with a 10µF capacitor to PGND. PVSSis the
negative supply of the headphone amplifiers. Bypass
PV

SS

with a 1µF capacitor to PGND. Connect PVSSto
CPVSS. The charge pump is powered by CPVDD.
CPV

DD

ranges from 3.0V to 5.5V and should be the
same potential as HPVDD. Bypass CPVDDwith a 1µF
capacitor to PGND. The charge pump inverts the volt­age at CPV

DD

, and the resulting voltage appears at
CPVSS. A 1µF capacitor must be connected between
C1N and C1P.

Power Supply and LDO Input (VDD)

The internal LDO and the remainder of the device is
powered by V

DD

. VDDranges from 4.5V to 5.5V.

Bypass V

DD

with a 0.1µF capacitor to GND and two
1µF capacitors in parallel to GND. Note additional bulk
capacitance is required at the device if long input
traces between VDDand the power source are used.

Input Filtering

The input capacitor (CIN), in conjunction with the ampli­fier input resistance (RIN), forms a highpass filter that
removes the DC bias from the incoming signal. The AC­coupling capacitor allows the amplifier to bias the sig­nal to an optimum DC level. Assuming zero source
impedance, the -3dB point of the highpass filter is
given by:

RINis the amplifier’s internal input resistance value
given in the

Electrical Characteristics

. Choose CINsuch

that f

-3dB

is well below the lowest frequency of interest.

Setting f

-3dB

too high affects the amplifier’s low fre­quency response. Use capacitors with adequately low
voltage coefficient dielectrics, such as 1206-sized X7R
ceramic capacitors. Capacitors with higher voltage
coefficients result in increased distortion at low fre­quencies (see Figure 7).

BIAS Capacitor

BIAS is the output of the internally generated DC bias
voltage. The BIAS bypass capacitor, C

BIAS

improves
PSRR and THD+N by reducing power supply and other
noise sources at the common-mode bias node, and
also generates the clickless/popless, startup/shutdown
DC bias waveforms for the speaker and headphone
amplifiers. Bypass BIAS with a 1µF capacitor to GND.

Charge-Pump Capacitor Selection

Use capacitors with an ESR less than 100mΩ for opti­mum performance. Low ESR ceramic capacitors mini­mize the output resistance of the charge pump. For
best performance over the extended temperature
range, select capacitors with an X7R dielectric.

Flying Capacitor (C1)

The value of the flying capacitor (C1) affects the load
regulation and output resistance of the charge pump. A
C1 value that is too small degrades the device’s ability
to provide sufficient current drive, which leads to a loss
of output voltage. Connect a 1µF capacitor between
C1P and C1N.

f

RC

dB

IN IN

− =

3

1

2π

Figure 7. Input Coupling Capacitor-Induced THD+N vs.
Frequency (Headphone Mode)

INPUT COUPLING CAPACITOR-INDUCED THD+N

vs. FREQUENCY (HEADPHONE MODE)

-50

-55

-60

-65

-70

THD+N (dB FS)

-75

-80

-85

-90

0402 6.3V X5R 10% 1μF

0603 10V X5R 10% 1μF

0805 25V X7R 10% 1μF

1206 25 X7R 10% 1μF

10 1000

FREQUENCY (Hz)

100

V

= -3dB FS

OUT

FS = 1V
RL = 32Ω

RMS

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

20 ______________________________________________________________________________________

Output Capacitor (C2)

The output capacitor value and ESR directly affect the
ripple at CPVSS. Increasing the value of C2 reduces
output ripple. Likewise, decreasing the ESR of C2
reduces both ripple and output resistance. Lower
capacitance values can be used in systems with low
maximum output power levels.

CPVDDBypass Capacitor (C3)

The CPVDDbypass capacitor (C3) lowers the output
impedance of the power supply and reduces the
impact of the MAX9789/MAX9790’s charge-pump
switching transients. Bypass CPVDDwith 1µF, the same
value as C1, and place it physically close to the CPV

DD

and CPGND pins.

Layout and Grounding

Proper layout and grounding are essential for optimum
performance. Use large traces for the power-supply
inputs and amplifier outputs to minimize losses due to
parasitic trace resistance, as well as route heat away
from the device. Good grounding improves audio per­formance, minimizes crosstalk between channels, and
prevents switching noise from coupling into the audio
signal. Connect PGND and GND together at a single
point on the PC board. Route PGND and all traces that
carry switching transients away from GND and the
traces and components in the audio signal path.

Connect C2 and C3 to the PGND plane. Connect PV

SS

and CPVSStogether at C2. Place the charge-pump
capacitors (C1, C2, and C3) as close as possible to
the device. Bypass PVDDwith a 0.1µF capacitor to
PGND. Place the bypass capacitors as close as possi­ble to the device.

Use large, low-resistance output traces. As load imped­ance decreases, the current drawn from the device out­puts increase. At higher current, the resistance of the
output traces decrease the power delivered to the load.
For example, if 2W is delivered from the speaker output
to a 4Ω load through a 100mΩ trace, 49mW is con­sumed in the trace. If power is delivered through a
10mΩ trace, only 5mW is consumed in the trace. Large
output, supply and GND traces also improve the power
dissipation of the device.

The MAX9789/MAX9790 thin QFN package features an
exposed thermal pad on its underside. This pad lowers
the package’s thermal resistance by providing a direct
heat conduction path from the die to the printed circuit
board. Connect the exposed thermal pad to GND by
using a large pad and multiple vias to the GND plane.

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 21

Block Diagrams

4.5V TO 5.5V

3V TO 5.5V

3V TO 5.5V

1.0µF1.0µF

1.0µF

1.0µF

1.0µF

1.0µF

0.1µF

SPKR_INL

SPKR_INR

HP_INL

HP_INR

HP_EN

MUTE 25

SPKR_EN 23

GAIN2

GAIN1

LDO_EN

LDO_SET

4.5V TO 5.5V

0.1µF

V

DD

30

3

2

27

26

22

CONTROL

32

31

4

1

LDO BLOCK

MAX9789

STEREO

BTL

AMPLIFIER

PV

DD

8, 18

6 OUTL+

OUTL-

7

OUTR+

20

OUTR-

19

BIAS

24

TO HPV

CHARGE

PUMP

DD

TO PV

16

HPL

SS

HPR

15

HPV

17

CPV

9

C1P

10

CPGND

11

C1N

12

1.0µF

3V TO 5.5V

DD

DD

C3
10µF

C1
1µF

TO CODEC

1.0µF

LOGIC PINS CONFIGURED FOR:
LDO_EN = 1, LDO ENABLED
SPKR_EN = 0, SPEAKER AMPLIFIERS ENABLED
HP_EN = 1, HEADPHONE AMPLIFIER ENABLED
MUTE = 1, MUTE DISABLED
GAIN1 = 0 GAIN = 0, 6dB SPEAKER GAIN

1.0µF

LDO_OUT

29

28

5, 21

1314

SS

C2

1.0µF

CPV

SS

PGNDGND

PV

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

22 ______________________________________________________________________________________

Block Diagrams (continued)

4.5V TO 5.5V

1.0μF

1.0μF

SPKR_INL

SPKR_INR

3

2

1.0μF

1.0μF

3V TO 5.5V

HP_INL

HP_INR

HP_EN

MUTE 25

SPKR_EN 23

GAIN2

GAIN1

27

26

22

32

31

0.1μF

CONTROL

MAX9790

STEREO

BTL

AMPLIFIER

V

DD

30 8, 18

PV

DD

TO HPV

CHARGE

PUMP

DD

TO PV

0.1μF

6 OUTL+

OUTL-

7

OUTR+

20

OUTR-

19

BIAS

24

1.0μF

16

HPL

SS

HPR

15

HPV

17

DD

CPV

9

DD

C1P

10

CPGND

11

3V TO 5.5V

C3
10μF

C1
1μF

C1N

12

4, 28

LOGIC PINS CONFIGURED FOR:
SPKR_EN = 0, SPEAKER AMPLIFIERS ENABLED
HP_EN = 1, HEADPHONE AMPLIFIER ENABLED
MUTE = 1, MUTE DISABLED
GAIN1 = 0 GAIN = 0, 6dB SPEAKER GAIN

5, 21

1314

SS

C2

1.0μF

CPV

SS

PGNDGND

PV

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 23

System Diagrams

V

LDO_OUT

SPKR_L

SPKR_R

HDA

CODEC

HP_R

HP_L

MONO

DGND AGND

0.1μF

μ

C

1μF 1μF

C

IN

1μF

C

IN

1μF

C

IN

1μF

C

IN

1μF

5.0V

C

3

1μF

1μF

1μF

5.0V

V

PV

DD

BIAS

SPKR_INL

SPKR_INR

HP_INR

HP_INL

DD

MAX9789

CPV

DD

C

1

C1P

C1N

SPKR_EN

HP_EN

LDO_EN

GAIN1

GAIN2

MUTE

GND

C

BULK

PGND

5.0V

HPV

OUTL+

OUTL-

OUTR+

OUTR-

HPL

HPR

LDO_SET

LDO_OUT

CPV

PV

CPGND

10μF

DD

Ω

4

Ω

4

4.75V

12V

1μF

C
1μF

2

1μF

SS

SS

100μF

0.47μF

0.47μF

0.47μF

1μF

0.01μF

FS2

FS1

G1

G2

SHDN

IN+

IN-

SS

REG

PGND

V

DD

MAX9713

AGND

OUT+

OUT-

C1P

C1N

CHOLD

Ω

8

0.1μF

V

DD

1μF

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

24 ______________________________________________________________________________________

System Diagrams (continued)

1μF

V

LDO_OUT

1μF

SPKR_L

1μF

SPKR_R

HDA

CODEC

HP1_R

HP1_L

HP2_R

HP2_L

AGNDDGND

1μF

1μF

μC

1μF 0.1μF

+3.3V

C

3

1μF

1μF

+5V

V

PV

DD

DD

SPKR_INL

SPKR_INR

HP_INR

HP_INL

MAX9789

CPV

DD

C

1

C1P

C1N

SPKR_EN

HP_EN

LDO_EN

GAIN2

GAIN1

MUTE

GND

PGND

+3.3V

HPV

OUTL+

OUTL-

OUTR+

OUTR-

HPL

HPR

LDO_SET

LDO_OUT

CP

VSS

P

VSS

CPGND

10μF

DD

HP1

4.75V

1μF 1μF

C

2

1μF

PGND

C1P

C1N

OUTL

OUTR

PV

SV

1μF

HP2

SS

SS

1μF

1μF

+3.3V

1μF

1μF

SHDNR

SHDNL

INR

INL

PV

DD

SV

DD

MAX4411

SGND

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 25

Simplified Block Diagrams

(continued)

Chip Information

PROCESS: BiCMOS

Pin Configurations

TOP VIEW

MUTE

HP_INR

HP_INL

GND

LDO_OUT

V

DD

GAIN1

GAIN2

*EP = EXPOSED PADDLE

SPKR_EN

BIAS

2324 22 20 19 18

25

26

27

28

29

30

31

+

32

12

LDO_SET

SPKR_INR

PGND

OUTR+

HP_EN

21

MAX9789

4567

3

PGND

LDO_EN

SPKR_INL

TQFN

OUTR-

EP*

OUTL+

DD

PV

OUTL-

OUTR-

EP*

DD

PV

OUTL-

DD

HPV

17

16

HPL

HPR

15

14

PV

SS

CPV

13

SS

12

C1N

CPGND

11

10

C1P

9

CPV

DD

8

DD

PV

DD

SPKR_EN

PGND

HPV

17

16

HPL

HPR

15

14

PV

SS

CPV

13

SS

12

C1N

CPGND

11

10

C1P

9

CPV

DD

8

DD

PV

MUTE

HP_INR

HP_INL

GND

N.C.

V

GAIN1

GAIN2

DD

BIAS

2324 22 20 19 18

25

26

27

28

29

30

31

+

32

12

N.C.

SPKR_INR

3

OUTR+

HP_EN

21

MAX9790

4567

GND

PGND

SPKR_INL

OUTL+

TQFN

*EP = EXPOSED PADDLE

SPKR_INR

SPKR_INL

HP_INR

HP_INL

SPEAKER SUPPLY

4.5V TO 5.5V

MAX9790

SPKR_EN
HP_EN

MUTE

GAIN1
GAIN2

HEADPHONE SUPPLY

3.0V TO 5.5V

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

26 ______________________________________________________________________________________

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

32 TQFN-EP T3255N-1

21-0140

Package Information

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.

QFN THIN.EPS

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker

Amplifiers and DirectDrive Headphone Amplifiers

______________________________________________________________________________________ 27

Package Information (continued)

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.

MAX9789/MAX9790

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

28

____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

Revision History

REVISION

NUMBER

2 8/08 Added MAX9789C to data sheet and made miscellaneous clarifications 1–11, 13, 14, 18

3 9/09 Corrected the Block Diagrams 21

REVISION

DATE

DESCRIPTION

PAGES

CHANGED