MAXIM MAX9788 User Manual

General Description

The MAX9788 features a mono Class G power amplifier
with an integrated inverting charge-pump power supply
specifically designed to drive the high capacitance of a
ceramic loudspeaker. The charge pump can supply
greater than 700mA of peak output current at 5.5VDC,
guaranteeing an output of 14V

P-P

.

The MAX9788 maximizes battery life by offering high­performance efficiency. Maxim’s proprietary Class G
output stage provides efficiency levels greater than
Class AB devices without the EMI penalties commonly
associated with Class D amplifiers.

The MAX9788 is ideally suited to deliver the high out­put-voltage swing required to drive ceramic/piezoelec­tric speakers.

The device utilizes fully differential inputs and outputs,
comprehensive click-and-pop suppression, shutdown
control, and soft-start circuitry. The MAX9788 is fully spec­ified over the -40°C to +85°C extended temperature range
and is available in small lead-free 28-pin TQFN (4mm x
4mm) or 20-bump WLP (2mm x 2.5mm) packages.

Features

♦ Integrated Charge-Pump Power Supply—No

Inductor Required

♦ 14V

P-P

Voltage Swing into Piezoelectric Speaker

♦ 2.7V to 5.5V Single-Supply Operation

♦ Clickless/Popless Operation

♦ Small Thermally Efficient Packages

4mm x 4mm 28-Pin TQFN
2mm x 2.5mm 20-Bump WLP

MAX9788

14V

P-P

, Class G Ceramic Speaker Driver

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

MAX9788

+

IN+

FB+

R

IN+

CPV

DD

2.7V TO 5.5V

R

IN-

C

IN

C

IN

IN-

FB-

OUT+

OUT-

-

CLASS G

OUTPUT

STAGE

CHARGE

PUMP

R

FB+

R

FB-

V

CC

CPGNDGND

Simplified Block Diagram

19-0710; Rev 3; 5/08

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.

Typical Application Circuit/Functional Diagram and Pin
Configurations appear at end of data sheet.

EVALUATION KIT

AVAILABLE

Cell Phones

Smartphones

MP3 Players

Personal Media Players

Handheld Gaming
Consoles

Notebook Computers

Applications

+

Denotes a lead-free package.
T = Tape and reel.
G45 indicates protective die coating.

*

EP = Exposed pad.

PART PIN-PACKAGE TEMP RANGE

MAX9788EWP+TG45 20 WLP -40°C to +85°C

MAX9788ETI+ 28 TQFN-EP* -40°C to +85°C

MAX9788

14V

P-P

, Class G Ceramic Speaker Driver

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= V

CPVDD

= V

SHDN

= 3.6V, V

GND

= V

CPGND

= 0V, R

IN+

= R

IN-

= 10kΩ, R

FB+

= R

FB-

= 10kΩ, RFS= 100kΩ, C1 = 4.7µF, C2 =

10µF; load connected between OUT+ and OUT-, Z

LOAD

= 10Ω + 1µF, unless otherwise stated; TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.) (Notes 2, 3)

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.

(Voltages with respect to GND.)
V

CC

, CPVDD.............................................................-0.3V to +6V

PV

SS

, SVSS...............................................................-6V to +0.3V

CPGND..................................................................-0.3V to +0.3V

OUT+, OUT-...................................(SV

SS

- 0.3V) to (VCC+ 0.3V)

IN+, IN-, FB+, FB- ......................................-0.3V to (V

CC

+ 0.3V)

C1N .........................................(PV

SS

- 0.3V) to (CPGND + 0.3V)

C1P ......................................(CPGND - 0.3V) to (CPV

DD

+ 0.3V)

FS, SHDN ...................................................-0.3V to (V

CC

+ 0.3V)

Continuous Current Into/Out of

OUT+, OUT-, V

CC

, GND, SVSS.....................................800mA

CPV

DD

, CPGND, C1P, C1N, PVSS.................................800mA

Any Other Pin ..................................................................20mA

Continuous Power Dissipation (T

A

= +70°C)
20-Bump WLP (derate 10.3mW/°C

above +70°C) (Note 1)..................................................827mW

28-Pin TQFN (derate 20.8mW/°C above +70°C) ........1667mW

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

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

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

Bump Temperature (soldering) Reflow............................+235°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, see www.maxim-ic.com/thermal-tutorial

.

GENERAL

Supply Voltage Range V

Quiescent Current I

Shutdown Current I

Turn-On Time t

Input DC Bias Voltage V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SHDN

CC

CC

ON

BIAS

Inferred from PSRR test 2.7 5.5 V

SHDN = GND 0.3 5 µA

Time from shutdown or power-on to full
operation

IN_ inputs (Note 4) 1.1 1.24 1.4 V

812mA

50 ms

I

= 0mA (slow mode) 55 83 110

Charge-Pump Oscillator
Frequency

SHDN Input Threshold
(Note 5)

SHDN Input Leakage Current ±1 µA

SPEAKER AMPLIFIER

Output Offset Voltage V

Click-and-Pop Level V

Voltage Gain A

Output Voltage V

f

OSC

OS

CP

OUT

LOAD

I

> 100mA (normal mode) 230 330 470

LOAD

V

IH

V

IL

TA = +25°C ±3 ±15

T

≤ TA ≤ T

MIN

Peak voltage into/out of shutdown
A-weighted, 32 samples per second
(Notes 6, 7)

(Notes 4, 8) 11.5 12 12.5 dB

V

f = 1kHz, 1% THD+N

MAX

VCC = 5V 7.1

VCC = 4.2V 5.9

VCC = 3.6V 5.1

= 3.0V 4.2

V

CC

1.4

-67 dBV

0.4

±20

kHz

V

V

mV

RMS

MAX9788

14V

P-P

, Class G Ceramic Speaker Driver

_______________________________________________________________________________________ 3

Note 2: All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Note 3: Testing performed with resistive and capacitive loads to simulate an actual ceramic/piezoelectric speaker load,

Z

L

= 1µF + 10Ω.

Note 4: Input DC bias voltage determines the maximum voltage swing of the input signal. Inputing a signal with a peak voltage

of greater than the input DC bias voltage results in clipping.

Note 5: 1.8V logic compatible.
Note 6: Amplifier/inputs AC-coupled to GND.
Note 7: Testing performed at room temperature with 10Ω resistive load in series with 1µF capacitive load connected across the BTL

output for speaker amplifier. Mode transitions are controlled by SHDN. V

CP

is the peak output transient expressed in dBV.

Note 8: Voltage gain is defined as: [V

OUT+

- V

OUT-

] / [V

IN+

- V

IN-

].

Note 9: PV

SS

is forced to -3.6V to simulate boosted rail.

Note 10: Dynamic range is calculated by measuring the RMS voltage difference between a -60dBFS output signal and the noise

floor, then adding 60dB. Full scale is defined as the output signal needed to achieve 1% THD+N.
R

IN_

and R

FB_

have 0.5% tolerance. The Class G output stage has 12dB of gain. Any gain or attenuation at the input

stage will add to or subtract from the gain of the Class G output.

ELECTRICAL CHARACTERISTICS (continued)

(VCC= V

CPVDD

= V

SHDN

= 3.6V, V

GND

= V

CPGND

= 0V, R

IN+

= R

IN-

= 10kΩ, R

FB+

= R

FB-

= 10kΩ, RFS= 100kΩ, C1 = 4.7µF, C2 =

10µF; load connected between OUT+ and OUT-, Z

LOAD

= 10Ω + 1µF, unless otherwise stated; TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.) (Notes 2, 3)

Output Voltage V

Continuous Output Power P

Power-Supply Rejection Ratio
(Note 4)

Total Harmonic Distortion Plus
Noise

Signal-to-Noise Ratio SNR V

Common-Mode Rejection Ratio CMRR fIN = 1kHz (Note 9) 68 dB

Dynamic Range DR A-weighted (Note 10)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

PSRR

THD+N

OUT

OUT

f = 10kHz, 1% THD+N,

= 1µF + 10Ω, no load

Z

L

1% THD+N, f = 1kHz,

= 8Ω

R

L

VCC = 2.7V to 5.5V 63 77

f = 217Hz, 200mV

f = 1kHz, 200mV

f = 20kHz, 200mV

ZL = 1µF + 10Ω, V

= 1µF + 10Ω, V

Z

L

OUT

VCC = 5V 6.5

VCC = 4.2V 5.4

VCC = 3.6V 4.7

V

= 3.0V 3.3

CC

VCC = 5V 2.4

VCC = 4.2V 1.67

VCC = 3.6V 1.25

= 3.0V 0.8

V

CC

ripple 77

P-P

ripple 77

P-P

ripple 58

P-P

= 1kHz / 1.9V

= 5.1V

OUT

= 1kHz / 4.0V

OUT

, A-weighted 108 dB

RMS

VCC = 5V 106

V

RMS

RMS

= 3.6V 105

CC

0.002

0.08

V

RMS

W

dB

%

dB

MAX9788

14V

P-P

, Class G Ceramic Speaker Driver

4 _______________________________________________________________________________________

Typical Operating Characteristics

(VCC= V

CPVDD

= V

SHDN

= 3.6V, V

GND

= V

CPGND

= 0V, R

IN+

= R

IN-

= 10kΩ, R

FB+

= R

FB-

= 10kΩ, RFS= 100kΩ, C1 = 4.7µF, C2 =

10µF, Z

L

= 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; TA= T

MIN

to T

MAX

, unless otherwise noted.

Typical values are at T

A

= +25°C.) (Notes 1, 2)

TOTAL HARMONIC DISTORTION PLUS

NOISE vs. FREQUENCY

MAX9788 toc01

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.01

0.1

1

10

0.001
10 100k

V

CC

= 2.7V

V

OUT

= 3V

RMS

V

OUT

= 1.25V

RMS

TOTAL HARMONIC DISTORTION PLUS

NOISE vs. FREQUENCY

MAX9788 toc02

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.01

0.1

1

10

0.001
10 100k

V

CC

= 3.6V

V

OUT

= 1.9V

RMS

V

OUT

= 4V

RMS

TOTAL HARMONIC DISTORTION PLUS

NOISE vs. FREQUENCY

MAX9788 toc03

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.01

0.1

1

10

0.001
10 100k

V

CC

= 5V

V

OUT

= 3V

RMS

V

OUT

= 5.9V

RMS

TOTAL HARMONIC DISTORTION PLUS

NOISE vs. OUTPUT VOLTAGE

MAX9788 toc04

OUTPUT VOLTAGE (V

RMS

)

THD+N (%)

3421

0.01

0.1

1

10

0.001
05

V

CC

= 2.7V

f

IN

= 10kHz

f

IN

= 1kHz

f

IN

= 20Hz

TOTAL HARMONIC DISTORTION PLUS

NOISE vs. OUTPUT VOLTAGE

MAX9788 toc05

OUTPUT VOLTAGE (V

RMS

)

THD+N (%)

53

4

1

2

0.01

0.1

1

10

0.001
06

V

CC

= 3.6V

f

IN

= 10kHz

f

IN

= 1kHz

f

IN

= 20Hz

TOTAL HARMONIC DISTORTION PLUS

NOISE vs. OUTPUT VOLTAGE

MAX9788 toc06

OUTPUT VOLTAGE (V

RMS)

THD+N (%)

7

6

5

4

231

0.01

0.1

1

10

0.001
08

f

IN

= 20Hz

f

IN

= 10kHz

f

IN

= 1kHz

V

CC

= 5V

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

MAX9788 toc07

FREQUENCY (Hz)

PSRR (dB)

10k1k100

-80

-70

-60

-50

-40

-30

-20

-10

0

-90
10 100k

V

RIPPLE

= 200mV

P-P

POWER CONSUMPTION

vs. OUTPUT VOLTAGE

MAX9788 toc08

OUTPUT VOLTAGE (V

RMS

)

POWER CONSUMPTION (mW)

3

2

1

25

50

75

100

0

04

V

CC

= 2.7V

f

IN

= 1kHz

1% THD+N

POWER CONSUMPTION

vs. OUTPUT VOLTAGE

MAX9788 toc09

OUTPUT VOLTAGE (V

RMS

)

4

31 2

25

50

75

100

150

125

175

200

0

05

V

CC

= 3.6V

f

IN

= 1kHz

1% THD+N

POWER CONSUMPTION (mW)