19-0710; Rev 3; 5/08
KIT
ATION
EVALU
BLE
AVAILA
14V
P-P
, Class G Ceramic Speaker Driver
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 high-
performance 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 out-
put-voltage swing required to drive ceramic/piezoelec-
tric speakers.
The device utilizes fully differential inputs and outputs,
comprehensive click-and-pop suppression, shutdown
control, and soft-start circuitry. The MAX9788 is fully spec-
ified 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
Ordering Information
PART
MAX9788EWP+TG45
MAX9788ETI+
PIN-PACKAGE
20 WLP
28 TQFN-EP*
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
+Denotes
a lead-free package.
T = Tape and reel.
G45 indicates protective die coating.
*EP
= Exposed pad.
Applications
Cell Phones
Smartphones
MP3 Players
Personal Media Players
Handheld Gaming
Consoles
Notebook Computers
Typical Application Circuit/Functional Diagram and Pin
Configurations appear at end of data sheet.
Simplified Block Diagram
2.7V TO 5.5V
V
CC
FB+
CPV
DD
MAX9788
C
IN
R
IN+
R
FB+
IN+
IN-
C
IN
R
IN-
R
FB-
FB-
GND
CHARGE
PUMP
CPGND
+
-
CLASS G
OUTPUT
STAGE
OUT+
OUT-
________________________________________________________________
Maxim Integrated Products
1
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.
14V
P-P
, Class G Ceramic Speaker Driver
MAX9788
ABSOLUTE MAXIMUM RATINGS
(Voltages with respect to GND.)
V
CC
, CPV
DD
.............................................................-0.3V to +6V
PV
SS
, SV
SS
...............................................................-6V to +0.3V
CPGND..................................................................-0.3V to +0.3V
OUT+, OUT-...................................(SV
SS
- 0.3V) to (V
CC
+ 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, SV
SS
.....................................800mA
CPV
DD
, CPGND, C1P, C1N, PV
SS
.................................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.
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.
ELECTRICAL CHARACTERISTICS
(V
CC
= V
CPVDD
= V
SHDN
= 3.6V, V
GND
= V
CPGND
= 0V, R
IN+
= R
IN-
= 10kΩ, R
FB+
= R
FB-
= 10kΩ, R
FS
= 100kΩ, C1 = 4.7µF, C2 =
10µF; load connected between OUT+ and OUT-, Z
LOAD
= 10Ω + 1µF, unless otherwise stated; T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Notes 2, 3)
PARAMETER
GENERAL
Supply Voltage Range
Quiescent Current
Shutdown Current
Turn-On Time
Input DC Bias Voltage
Charge-Pump Oscillator
Frequency
SHDN
Input Threshold
(Note 5)
SHDN
Input Leakage Current
SPEAKER AMPLIFIER
Output Offset Voltage
V
OS
T
A
= +25°C
T
MIN
≤
T
A
≤
T
MAX
Peak voltage into/out of shutdown
A-weighted, 32 samples per second
(Notes 6, 7)
(Notes 4, 8)
V
CC
= 5V
Output Voltage
V
OUT
f = 1kHz, 1% THD+N
V
CC
= 4.2V
V
CC
= 3.6V
V
CC
= 3.0V
11.5
-67
12
7.1
5.9
5.1
4.2
V
RMS
12.5
±3
±15
±20
mV
V
CC
I
CC
I
SHDN
t
ON
V
BIAS
SHDN
= GND
Time from shutdown or power-on to full
operation
IN_ inputs (Note 4)
I
LOAD
= 0mA (slow mode)
f
OSC
I
LOAD
> 100mA (normal mode)
V
IH
V
IL
230
1.4
0.4
±1
330
470
V
µA
1.1
55
Inferred from PSRR test
2.7
8
0.3
50
1.24
83
1.4
110
kHz
5.5
12
5
V
mA
µA
ms
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Click-and-Pop Level
Voltage Gain
V
CP
A
V
dBV
dB
2
_______________________________________________________________________________________
14V
P-P
, Class G Ceramic Speaker Driver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= V
CPVDD
= V
SHDN
= 3.6V, V
GND
= V
CPGND
= 0V, R
IN+
= R
IN-
= 10kΩ, R
FB+
= R
FB-
= 10kΩ, R
FS
= 100kΩ, C1 = 4.7µF, C2 =
10µF; load connected between OUT+ and OUT-, Z
LOAD
= 10Ω + 1µF, unless otherwise stated; T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Notes 2, 3)
PARAMETER
SYMBOL
CONDITIONS
V
CC
= 5V
Output Voltage
V
OUT
f = 10kHz, 1% THD+N,
Z
L
= 1µF + 10Ω, no load
V
CC
= 4.2V
V
CC
= 3.6V
V
CC
= 3.0V
V
CC
= 5V
Continuous Output Power
P
OUT
1% THD+N, f = 1kHz,
R
L
= 8Ω
V
CC
= 2.7V to 5.5V
Power-Supply Rejection Ratio
(Note 4)
PSRR
f = 217Hz, 200mV
P-P
ripple
f = 1kHz, 200mV
P-P
ripple
f = 20kHz, 200mV
P-P
ripple
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Common-Mode Rejection Ratio
Dynamic Range
THD+N
SNR
CMRR
DR
Z
L
= 1µF + 10Ω, V
OUT
= 1kHz / 1.9V
RMS
Z
L
= 1µF + 10Ω, V
OUT
= 1kHz / 4.0V
RMS
V
OUT
= 5.1V
RMS
, A-weighted
f
IN
= 1kHz (Note 9)
A-weighted (Note 10)
V
CC
= 5V
V
CC
= 3.6V
V
CC
= 4.2V
V
CC
= 3.6V
V
CC
= 3.0V
63
MIN
TYP
6.5
5.4
4.7
3.3
2.4
1.67
1.25
0.8
77
77
77
58
0.002
0.08
108
68
106
105
%
dB
dB
dB
dB
W
V
RMS
MAX
UNITS
MAX9788
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Testing performed with resistive and capacitive loads to simulate an actual ceramic/piezoelectric speaker load,
Z
L
= 1µF + 10Ω.
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.
1.8V logic compatible.
Amplifier/inputs AC-coupled to GND.
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.
Voltage gain is defined as: [V
OUT+
- V
OUT-
] / [V
IN+
- V
IN-
].
PV
SS
is forced to -3.6V to simulate boosted rail.
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.
_______________________________________________________________________________________
3
14V
P-P
, Class G Ceramic Speaker Driver
MAX9788
Typical Operating Characteristics
(V
CC
= V
CPVDD
= V
SHDN
= 3.6V, V
GND
= V
CPGND
= 0V, R
IN+
= R
IN-
= 10kΩ, R
FB+
= R
FB-
= 10kΩ, R
FS
= 100kΩ, C1 = 4.7µF, C2 =
10µF, Z
L
= 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; T
A
= 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
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX9788 toc02
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
V
CC
= 5V
1
MAX9788 toc03
10
V
CC
= 2.7V
1
10
V
CC
= 3.6V
1
THD+N (%)
10
THD+N (%)
0.1
0.1
THD+N (%)
V
OUT
= 3V
RMS
V
OUT
= 4V
RMS
0.1
V
OUT
= 5.9V
RMS
0.01
V
OUT
= 1.25V
RMS
0.01
V
OUT
= 1.9V
RMS
0.01
V
OUT
= 3V
RMS
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT VOLTAGE
MAX9788 toc04
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT VOLTAGE
V
CC
= 3.6V
f
IN
= 10kHz
f
IN
= 1kHz
0.1
MAX9788 toc05
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT VOLTAGE
V
CC
= 5V
1
THD+N (%)
f
IN
= 10kHz
f
IN
= 1kHz
0.1
MAX9788 toc06
10
V
CC
= 2.7V
1
THD+N (%)
f
IN
= 10kHz
f
IN
= 1kHz
0.1
10
10
1
THD+N (%)
0.01
f
IN
= 20Hz
0.001
0
1
2
3
4
5
OUTPUT VOLTAGE (V
RMS
)
0.01
f
IN
= 20Hz
0.001
0
1
2
3
4
5
6
OUTPUT VOLTAGE (V
RMS
)
0.01
f
IN
= 20Hz
0.001
0
1
2
3
4
5
6
7
8
OUTPUT VOLTAGE (V
RMS)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX9788 toc07
POWER CONSUMPTION
vs. OUTPUT VOLTAGE
MAX9788 toc08
POWER CONSUMPTION
vs. OUTPUT VOLTAGE
175
POWER CONSUMPTION (mW)
150
125
100
75
50
25
0
4
0
1
V
CC
= 3.6V
f
IN
= 1kHz
1% THD+N
2
3
4
OUTPUT VOLTAGE (V
RMS
)
5
MAX9788 toc09
0
-10
-20
-30
PSRR (dB)
-40
-50
-60
-70
-80
-90
10
100
1k
FREQUENCY (Hz)
10k
V
RIPPLE
= 200mV
P-P
100
200
POWER CONSUMPTION (mW)
75
50
25
V
CC
= 2.7V
f
IN
= 1kHz
1% THD+N
0
1
2
3
0
100k
OUTPUT VOLTAGE (V
RMS
)
4
_______________________________________________________________________________________
14V
P-P
, Class G Ceramic Speaker Driver
Typical Operating Characteristics (continued)
(V
CC
= V
CPVDD
= V
SHDN
= 3.6V, V
GND
= V
CPGND
= 0V, R
IN+
= R
IN-
= 10kΩ, R
FB+
= R
FB-
= 10kΩ, R
FS
= 100kΩ, C1 = 4.7µF, C2 =
10µF, Z
L
= 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°C.) (Notes 1, 2)
POWER CONSUMPTION
vs. OUTPUT VOLTAGE
MAX9788 toc10
MAX9788
STARTUP WAVEFORM
MAX9788 toc11
SHUTDOWN WAVEFORM
MAX9788 toc12
350
300
POWER CONSUMPTION (mW)
250
200
150
100
50
0
0
1
2
3
4
5
6
7
V
CC
= 5V
f
IN
= 1kHz
1% THD+N
SHDN
5V/div
SHDN
5V/div
OUT+ - OUT-
500mV/div
OUT+ - OUT-
500mV/div
10ms/div
10ms/div
OUTPUT VOLTAGE (V
RMS
)
CLASS G OUTPUT WAVEFORM
MAX9788 toc13
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9788 toc14
12
10
SUPPLY CURRENT (mA)
8
6
4
2
OUT+
5V/div
OUT-
5V/div
OUT+ - OUT-
10V/div
1% THD+N
0
200μs/div
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
SUPPLY VOLTAGE (V)
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
MAX9788 toc15
SUPPLY CURRENT
vs. OUTPUT VOLTAGE
MAX9788 toc16
1.0
0.9
SHUTDOWN CURRENT (μA)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
70
60
SUPPLY CURRENT (mA)
50
40
30
20
10
0
V
CC
= 5V
f
IN
= 1kHz
0
1
2
3
4
5
6
7
6.0
SUPPLY VOLTAGE (V)
OUTPUT VOLTAGE (V
RMS
)
_______________________________________________________________________________________
5
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