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 14VP-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 UCSP™ (2mm x 2.5mm) packages.
Features
oIntegrated Charge-Pump Power Supply—No
Inductor Required
o14VP-P Voltage Swing into Piezoelectric Speaker
o2.7V to 5.5V Single-Supply Operation
oClickless/Popless Operation
oSmall Thermally Efficient Packages
4mm x 4mm 28-Pin TQFN
2mm x 2.5mm 20-Bump UCSP
MAX9788
14VP-P, Class G Ceramic Speaker Driver
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
MAX9788
+
IN+
FB+
RIN+
CPVDD
2.7V TO 5.5V
RIN-
CIN
CIN
IN-
FB-
OUT+
OUT-
-
CLASS G
OUTPUT
STAGE
CHARGE
PUMP
RFB+
RFB-
VCC
CPGNDGND
Simplified Block Diagram
19-0710; Rev 0; 12/06
For pricing, delivery, and ordering information, please contact Maxim/Dallas 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
PART TEMP RANGE PIN-
PACKAGE
PKG
CODE
MAX9788EBP+T* -40°C to +85°C 20 UCSP-20 B20-7
MAX9788ETI+ -40°C to +85°C 28 TQFN-EP** T2844-1
+
Denotes lead-free package.
*
Future product—contact factory for availability.
**
EP = Exposed pad.
UCSP is a trademark of Maxim Integrated Products, Inc.
MAX9788
14VP-P, Class G Ceramic Speaker Driver
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF;
load connected between OUT+ and OUT-, ZLOAD = 10Ω+ 1µF, unless otherwise stated; TA= TMIN to TMAX, unless otherwise noted.
Typical values are at TA= +25°C.) (Notes 1, 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.
(Voltages with respect to GND.)
VCC, CPVDD .............................................................-0.3V to +6V
PVSS, SVSS ...............................................................-6V to +0.3V
CPGND..................................................................-0.3V to +0.3V
OUT+, OUT-...................................(SVSS - 0.3V) to (VCC + 0.3V)
IN+, IN-, FB+, FB- ......................................-0.3V to (VCC + 0.3V)
C1N .........................................(PVSS - 0.3V) to (CPGND + 0.3V)
C1P ......................................(CPGND - 0.3V) to (CPVDD + 0.3V)
FS, SHDN ...................................................-0.3V to (VCC + 0.3V)
Continuous Current Into/Out of
OUT+, OUT-, VCC, GND, SVSS .....................................800mA
CPVDD, CPGND, C1P, C1N, PVSS.................................800mA
Any Other Pin ..................................................................20mA
Duration of OUT+, OUT- Short Circuit to
VCC, GND, CPVDD, CPGND ..................................Continuous
Continuous Power Dissipation (TA= +70°C)
20-Bump UCSP (derate 10.3mW/°C above +70°C) .....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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
GENERAL
Supply Voltage Range VCC Inferred from PSRR test 2.7 5.5 V
Quiescent Current ICC 812mA
Shutdown Current ISHDN SHDN = GND 0.3 5 µA
Turn-On Time tON Time from shutdown or power-on to full
operation 50 ms
Input DC Bias Voltage VBIAS IN_ inputs (Note 3) 1.1 1.24 1.4 V
ILOAD = 0mA (slow mode) 55 83 110
Charge-Pump Oscillator
Frequency fOSC
ILOAD > 100mA (normal mode) 230 330 470
kHz
VIH 1.4
SHDN Input Threshold
(Note 4) VIL 0.4 V
SHDN Input Leakage Current ±1 µA
SPEAKER AMPLIFIER
TA = +25°C ±3 ±15
Output Offset Voltage VOS TMIN ≤ TA ≤ TMAX ±20 mV
Click-and-Pop Level VCP
Peak voltage into/out of shutdown
A-weighted, 32 samples per second
(Notes 5, 6)
-67 dBV
Voltage Gain AV(Notes 3, 7) 11.5 12 12.5 dB
VCC = 5V 7.1
VCC = 4.2V 5.9
VCC = 3.6V 5.1
Output Voltage VOUT f = 1kHz, 1% THD+N
VCC = 3.0V 4.2
VRMS
MAX9788
14VP-P, Class G Ceramic Speaker Driver
_______________________________________________________________________________________ 3
Note 1: All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Note 2: Testing performed with resistive and capacitive loads to simulate an actual ceramic/piezoelectric speaker load,
ZL= 1µF + 10Ω.
Note 3: 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 4: 1.8V logic compatible.
Note 5: Amplifier/inputs AC-coupled to GND.
Note 6: Testing performed at room temperature with 10Ωresistive load in series with 1µF capacitive load connected across the BTL
output for speaker amplifier. Mode transitions are controlled by SHDN. VCP is the peak output transient expressed in dBV.
Note 7: Voltage gain is defined as: [VOUT+ - VOUT-] / [VIN+ - VIN-].
Note 8: PVSS is forced to -3.6V to simulate boosted rail.
Note 9: 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.
RIN_ and RFB_ 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.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
VCC = 5V 6.5
VCC = 4.2V 5.4
VCC = 3.6V 4.7
Output Voltage VOUT f = 10kHz, 1% THD+N,
ZL = 1µF + 10Ω, no load
VCC = 3.0V 3.3
VRMS
VCC = 5V 2.4
VCC = 4.2V 1.67
VCC = 3.6V 1.25
Continuous Output Power POUT 1% THD+N, f = 1kHz,
RL = 8Ω
VCC = 3.0V 0.8
W
VCC = 2.7V to 5.5V 63 77
f = 217Hz, 200mVP-P ripple 77
f = 1kHz, 200mVP-P ripple 77
Power-Supply Rejection Ratio
(Note 3) PSRR
f = 20kHz, 200mVP-P ripple 58
dB
ZL = 1µF + 10Ω, VOUT = 1kHz / 1.9VRMS 0.002
Total Harmonic Distortion Plus
Noise THD+N ZL = 1µF + 10Ω, VOUT = 1kHz / 4.0VRMS 0.08 %
Signal-to-Noise Ratio SNR VOUT = 5.1VRMS, A-weighted 108 dB
Common-Mode Rejection Ratio CMRR fIN = 1kHz (Note 8) 68 dB
VCC = 5V 106
Dynamic Range DR A-weighted (Note 9) VCC = 3.6V 105 dB
ELECTRICAL CHARACTERISTICS (continued)
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF;
load connected between OUT+ and OUT-, ZLOAD = 10Ω+ 1µF, unless otherwise stated; TA= TMIN to TMAX, unless otherwise noted.
Typical values are at TA= +25°C.) (Notes 1, 2)
MAX9788
14VP-P, Class G Ceramic Speaker Driver
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF,
ZL= 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX, unless otherwise noted.
Typical values are at TA= +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
VCC = 2.7V
VOUT = 3VRMS
VOUT = 1.25VRMS
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX9788 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
10
0.001
10 100k
VCC = 3.6V
VOUT = 1.9VRMS
VOUT = 4VRMS
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX9788 toc03
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
10
0.001
10 100k
VCC = 5V
VOUT = 3VRMS
VOUT = 5.9VRMS
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT VOLTAGE
MAX9788 toc04
OUTPUT VOLTAGE (VRMS)
THD+N (%)
3421
0.01
0.1
1
10
0.001
05
VCC = 2.7V
fIN = 10kHz
fIN = 1kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT VOLTAGE
MAX9788 toc05
OUTPUT VOLTAGE (VRMS)
THD+N (%)
53 4
12
0.01
0.1
1
10
0.001
06
VCC = 3.6V
fIN = 10kHz
fIN = 1kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT VOLTAGE
MAX9788 toc06
OUTPUT VOLTAGE (VRMS)
THD+N (%)
7
6
5
4
231
0.01
0.1
1
10
0.001
08
fIN = 20Hz
fIN = 10kHz
fIN = 1kHz
VCC = 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
VRIPPLE = 200mVP-P
POWER CONSUMPTION
vs. OUTPUT VOLTAGE
MAX9788 toc08
OUTPUT VOLTAGE (VRMS)
POWER CONSUMPTION (mW)
3
2
1
25
50
75
100
0
04
VCC = 2.7V
fIN = 1kHz
1% THD+N
POWER CONSUMPTION
vs. OUTPUT VOLTAGE
MAX9788 toc09
OUTPUT VOLTAGE (VRMS)
4
31 2
25
50
75
100
150
125
175
200
0
05
VCC = 3.6V
fIN = 1kHz
1% THD+N
POWER CONSUMPTION (mW)
MAX9788
14VP-P, Class G Ceramic Speaker Driver
_______________________________________________________________________________________
5
POWER CONSUMPTION
vs. OUTPUT VOLTAGE
MAX9788 toc10
OUTPUT VOLTAGE (VRMS)
POWER CONSUMPTION (mW)
654321
50
100
150
200
250
300
350
0
07
VCC = 5V
fIN = 1kHz
1% THD+N
STARTUP WAVEFORM
MAX9788 toc11
10ms/div
SHDN
5V/div
OUT+ - OUT-
500mV/div
SHUTDOWN WAVEFORM
MAX9788 toc12
10ms/div
SHDN
5V/div
OUT+ - OUT-
500mV/div
Typical Operating Characteristics (continued)
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF,
ZL= 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX, unless otherwise noted.
Typical values are at TA= +25°C.) (Notes 1, 2)
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
MAX9788 toc15
SUPPLY VOLTAGE (V)
SHUTDOWN CURRENT (μA)
5.55.04.0 4.53.53.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
2.5 6.0
SUPPLY CURRENT
vs. OUTPUT VOLTAGE
MAX9788 toc16
OUTPUT VOLTAGE (VRMS)
SUPPLY CURRENT (mA)
6
45
3
2
107
10
20
30
40
50
60
70
0
VCC = 5V
fIN = 1kHz
CLASS G OUTPUT WAVEFORM
MAX9788 toc13
200μs/div
OUT+ - OUT-
10V/div
OUT-
5V/div
OUT+
5V/div
1% THD+N
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9788 toc14
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.55.04.0 4.53.53.0
4
6
8
2
10
12
0
2.5 6.0
MAX9788
14VP-P, Class G Ceramic Speaker Driver
6 _______________________________________________________________________________________
OUTPUT AMPLITUDE
vs. FREQUENCY
MAX9788 toc17
FREQUENCY (Hz)
OUTPUT AMPLITUDE (VRMS)
10k1k100
1
2
3
4
5
6
7
8
0
10 100k
VCC = 3.6V
VCC = 2.7V
VCC = 5V
FREQUENCY RESPONSE
MAX9788 toc18
FREQUENCY (Hz)
GAIN (dB)
10k1k100
2
4
6
8
10
12
14
16
18
20
0
10 100k
VOUT = 2VRMS
Pin Description
Typical Operating Characteristics (continued)
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF,
ZL= 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX, unless otherwise noted.
PIN
TQFN UCSP NAME FUNCTION
1B2SHDN Shutdown
2, 5, 6, 8, 11, 17,
19, 23, 25, 28 — N.C. No Connection. No internal connection.
3 A2 C1P Charge-Pump Flying Capacitor, Positive Terminal. Connect a 4.7µF
capacitor between C1P and C1N.
4 A3 CPVDD Charge-Pump Positive Supply
7 A4 FB- Negative Amplifier Feedback
9 A5 IN- Negative Amplifier Input
10 B5 IN+ Positive Amplifier Input
12 B4 FB+ Positive Amplifier Feedback
13 C5 FS Charge-Pump Frequency Set. Connect a 100kΩ resistor from FS to
GND to set the charge-pump switching frequency.
14, 22 D1, D5 VCC Supply Voltage. Bypass with a 10µF capacitor to GND.
15, 21 C2, C4 SVSS Amplifier Negative Power Supply. Connect to PVSS.
16 D4 OUT- Negative Amplifier Output
18 D3 GND Ground
20 D2 OUT+ Positive Amplifier Output
24 C1 PVSS Charge-Pump Output. Connect a 10µF capacitor between PVSS and
CPGND.
26 B1 C1N Charge-Pump Flying Capacitor, Negative Terminal. Connect a 4.7µF
capacitor between C1N and C1P.
27 A1 CPGND Charge-Pump Ground. Connect to GND.
EP — EP Exposed Pad. Connect the TQFN EP to GND.
MAX9788
14VP-P, Class G Ceramic Speaker Driver
_______________________________________________________________________________________ 7
Detailed Description
The MAX9788 Class G power amplifier with inverting
charge pump is the latest in linear amplifier technology.
The Class G output stage offers improved performance
over a Class AB amplifier while increasing efficiency to
extend battery life. The integrated inverting charge
pump generates a negative supply capable of deliver-
ing greater than 700mA.
The Class G output stage and the inverting charge
pump allow the MAX9788 to deliver a 14VP-P voltage
swing, up to two times greater than a traditional single-
supply linear amplifier.
Class G Operation
The MAX9788 Class G amplifier is a linear amplifier that
operates within a low (VCC to GND) and high (VCC to
SVSS) supply range. Figure 1 illustrates the transition
from the low to high supply range. For small signals,
the device operates within the lower (VCC to GND) sup-
ply range. In this range, the operation of the device
is identical to a traditional single-supply Class AB
amplifier where:
ILOAD = IN1
As the output signal increases so a wider supply is need-
ed, the device begins its transition to the higher supply
range (VCC to SVSS) for the large signals. To ensure a
seamless transition between the low and high supply
ranges, both of the lower transistors are on so that:
ILOAD = IN1 + IN2
As the output signal continues to increase, the transi-
tion to the high supply is complete. The device then
operates in the higher supply range, where the opera-
tion of the device is identical to a traditional dual-sup-
ply Class AB amplifier where:
ILOAD = IN2
During operation, the output common-mode voltage of
the MAX9788 adjusts dynamically as the device transi-
tions between supply ranges.
Utilizing a Class G output stage with an inverting
charge pump allows the MAX9788 to realize a 20VP-P
output swing with a 5V supply.
ON
IN1 IN1
P
N1
N2
IP
ON
OFF
ZL
VCC
SVSS
LOW SUPPLY RANGE OPERATION
IP = IN1
ON
IN2 IN2
P
N1
N2
IP
ON
ON
ZL
VCC
BTL CLASS G SUPPLY TRANSITION
SVSS
SUPPLY TRANSITION
IP = IN1 + IN2
ON P
N1
N2
IP
OFF
ON
ZL
VCC
SVSS
HIGH SUPPLY RANGE OPERATION
IP = IN2
Figure 1. Class G Supply Transition
MAX9788
14VP-P, Class G Ceramic Speaker Driver
8 _______________________________________________________________________________________
Inverting Charge Pump
The MAX9788 features an integrated charge pump with an
inverted supply rail that can supply greater than 700mA
over the positive 2.7V to 5.5V supply range. In the case of
the MAX9788, the charge pump generates the negative
supply rail (PVSS) needed to create the higher supply
range, which allows the output of the device to operate
over a greater dynamic range as the battery supply col-
lapses over time.
Shutdown Mode
The MAX9788 has a shutdown mode that reduces
power consumption and extends battery life. Driving
SHDN low places the MAX9788 in a low-power (0.3µA)
shutdown mode. Connect SHDN to VCC for normal
operation.
Click-and-Pop Suppression
The MAX9788 Class G amplifier features Maxim’s com-
prehensive, industry-leading click-and-pop suppres-
sion. During startup, the click-and-pop suppression
circuitry eliminates any audible transient sources inter-
nal to the device.
Applications Information
Differential Input Amplifier
The MAX9788 features a differential input configuration,
making the device compatible with many CODECs, and
offering improved noise immunity over a single-ended
input amplifier. In devices such as PCs, noisy digital
signals can be picked up by the amplifier’s input
traces. The signals appear at the amplifier’s inputs as
common-mode noise. A differential input amplifier
amplifies the difference of the two inputs and signals
common to both inputs are canceled out. When config-
ured for differential inputs, the voltage gain of the
MAX9788 is set by:
where AVis the desired voltage gain in dB. RIN+ should
be equal to RIN-, and RFB+ should be equal to RFB-.
The Class G output stage has a fixed gain of 4V/V
(12dB). Any gain or attenuation set by the external
input stage resistors will add to or subtract from this
fixed gain. See Figure 2.
In differential input configurations, the common-mode
rejection ratio (CMRR) is primarily limited by the exter-
nal resistor and capacitor matching. Ideally, to achieve
the highest possible CMRR, the following external com-
ponents should be selected where:
and
CC
IN IN+=−
R
R
R
R
FB
IN
FB
IN
+
+
=−
−
AR
RdB
VFB
IN
=×
⎛
⎝
⎜
⎞
⎠
⎟
⎡
⎣
⎢
⎢
⎤
⎦
⎥
⎥
()
20 4log
_
_
MAX9788
+
IN+
FB+
RIN+
RIN-
CIN+
CIN-
IN-
FB-
-
CLASS G
OUTPUT
STAGE
RFB+
RFB-
Figure 2. Gain Setting
Driving a Ceramic Speaker
Applications that require thin cases, such as today’s
mobile phones, demand that external components
have a small form factor. Dynamic loudspeakers that
use a cone and voice coil typically cannot conform to
the height requirements. The option for these applica-
tions is to use a ceramic/piezoelectric loudspeaker.
Ceramic speakers are much more capacitive than a con-
ventional loudspeaker. Typical capacitance values for
such a speaker can be greater than 1µF. High peak-to-
peak voltage drive is required to achieve acceptable
sound pressure levels. The high output voltage require-
ment coupled with the capacitive nature of the speaker
demand that the amplifier supply much more current at
high frequencies than at lower frequencies. Above 10kHz,
the typical speaker impedance can be less than 16Ω.
The MAX9788 is ideal for driving a capacitive ceramic
speaker. The high charge-pump current limit allows for a
flat frequency response out to 20kHz while maintaining
high output voltage swings. See the Frequency Response
graph in the
Typical Operating Characteristics
. Figure 3
shows a typical circuit for driving a ceramic speaker.
A 10Ωseries resistance is recommended between the
amplifier output and the ceramic speaker load to ensure
the output of the amplifier sees some fixed resistance at
high frequencies when the speaker is essentially an
electrical short.
Component Selection
Input-Coupling Capacitor
The AC-coupling capacitors (CIN_) and input resistors
(RIN_) form highpass filters that remove any DC bias
from an input signal (see the
Functional Diagram/
Typical Operating Circuit
). CIN_ blocks DC voltages
from the amplifier input. The -3dB point of the highpass
filter, assuming zero source impedance due to the
input signal source, is given by:
Ceramic speakers generally perform best at frequen-
cies greater than 1kHz. Low frequencies can deflect
the piezoelectric speaker element so that high frequen-
cies cannot be properly reproduced. This can cause
distortion in the speaker’s usable frequency band.
Select a CIN so the f-3dB closely matches the low fre-
quency response of the ceramic speaker. Use capaci-
tors with low-voltage coefficient dielectrics. Aluminum
electrolytic, tantalum, or film dielectric capacitors are
good choices for AC-coupling capacitors. Capacitors
with high-voltage coefficients, such as ceramics (non-
C0G dielectrics), can result in increased distortion at
low frequencies.
Charge-Pump Capacitor Selection
Use capacitors with an ESR less than 50mΩfor opti-
mum performance. Low-ESR ceramic capacitors mini-
mize 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. Increasing the value
of C1 improves load regulation and reduces the charge-
pump output resistance to an extent. Above 1µF, the on-
resistance of the switches and the ESR of C1 and C2
dominate. A 4.7µF capacitor is recommended.
fRC
Hz
dB IN IN
−=××
()
3
1
2π__
MAX9788
14VP-P, Class G Ceramic Speaker Driver
_______________________________________________________________________________________ 9
MAX9788
OUT+ RL
OUT-
CLASS G
OUTPUT
STAGE
Figure 3. Driving a Ceramic Speaker
MAX9788
Hold Capacitor (C2)
The output capacitor value and ESR directly affect the
ripple at PVSS. Increasing C2 reduces output ripple.
Likewise, decreasing the ESR of C2 reduces both rip-
ple and output resistance. A 10µF capacitor is recom-
mended.
Charge-Pump Frequency Set Resistor (R
FS
)
The charge pump operates in two modes. When the
charge pump is loaded below 100mA, it operates in a
slow mode where the oscillation frequency is reduced to
1/4 of its normal operating frequency. Once loaded, the
charge-pump oscillation frequency returns to normal
operation. In applications where the design may be sen-
sitive to the operating charge-pump oscillation frequen-
cy, the value of the external resistor RFS can be changed
to adjust the charge-pump oscillation frequency shown
in Figure 4. A 100kΩresistor is recommended.
Ceramic Speaker Impedance
Characteristics
A 1µF capacitor is a good model for the ceramic
speaker as it best approximates the impedance of a
ceramic speaker over the audio band. When selecting
a capacitor to simulate a ceramic speaker, the voltage
rating or the capacitor must be equal to or higher than
the expected output voltage swing. See Figure 5.
Series Load Resistor
The capacitive nature of the ceramic speaker results in
very low impedances at high frequencies. To prevent
the ceramic speaker from shorting the MAX9788 output
at high frequencies, a series load resistor must be
used. The output load resistor and the ceramic speaker
create a lowpass filter. To set the rolloff frequency of
the output filter, the approximate capacitance of the
speaker must be known. This information can be
obtained from bench testing or from the ceramic
speaker manufacturer. A series load resistor greater
than 10Ωis recommended. Set the lowpass filter cutoff
frequency with the following equation:
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow tempera-
ture profile, as well as the latest information on reliability
testing results, go to the Maxim website at www.maxim-
ic.com/ucsp for the application note,
UCSP—A Wafer-
Level Chip-Scale Package
.
fRC Hz
LP L SPEAKER
=××
()
1
2π
14VP-P, Class G Ceramic Speaker Driver
10 ______________________________________________________________________________________
CHARGE-PUMP OSCILLATION
FREQUENCY vs. RFS
MAX9788 fig04
RFS (kΩ)
CHARGE-PUMP OSCILLATION FREQUENCY (kHz)
12510075
250
300
350
400
450
500
550
600
200
50 150
ILOAD > 100mA
IMPEDANCE vs. FREQUENCY
MAX9788 fig05
FREQUENCY (Hz)
IMPEDANCE (Ω)
1010.10.01
100
1k
10k
100k
1M
10
0.001 100
1μF CAPACITOR
CERAMIC
SPEAKER
Figure 4. Charge-Pump Oscillation Frequency vs. RFS Figure 5. Ceramic Speaker and Capacitor Impedance
MAX9788
14VP-P, Class G Ceramic Speaker Driver
______________________________________________________________________________________ 11
Typical Application Circuit/Functional Diagram
MAX9788
+
IN+
FB+
1 (B2)
0.1μF
4 (A3)
14, 22
(D1, D5)
RIN+
10kΩ
VCC
RIN-
10kΩ
CIN
0.47μF
CIN
0.47μF
IN-
20 (D2)
16 (D4)
FB-
OUT+
13 (C5)
( ) UCSP PACKAGE
DEVICE SHOWN WITH AV = 12dB
*SYSTEM-LEVEL REQUIREMENT TYPICALLY 10μF
FS
OUT-
10 (B5)
7 (A4)
9 (A5)
12 (B4)
18 (D3) 27 (A1) 26 (B1) 3 (A2) 24 (C1) 15, 21
(C2, C4)
-
CLASS G
OUTPUT
STAGE
CHARGE
PUMP
RFB+
10kΩ
RFB-
10kΩ
SHDN
CPGND PVSS SVSS
C1N C1P
C2
10μF
RFS
100kΩ
GND
CPVDD
C1
4.7μF
VDD
*
RL
10Ω
MAX9788
14VP-P, Class G Ceramic Speaker Driver
12 ______________________________________________________________________________________
Pin Configurations
28
27
26
25
24
23
22
8
9
10
11
12
13
14
15
16
17
18
19
20
21
7
6
EP*
*EXPOSED PAD.
5
4
3
2
1
+
MAX9788
THIN QFN
TOP VIEW
N.C.
SHDN
C1P
CPVDD
N.C.
N.C.
FB-
N.C.
CPGND
C1N
N.C.
PVSS
N.C.
VCC
SVSS
OUT+
N.C.
GND
N.C.
OUT-
SVSS
VCC
FS
FB+
N.C.
IN+
IN-
N.C.
TOP VIEW
(BUMP SIDE DOWN)
UCSP
CPVDD
C1P IN-
CPGND
1
A
B
D
23 5
C
FB-
SHDN IN+
C1N FB+
SVSS FS
PVSS SVSS
GND
OUT+ VCC
VCC OUT-
4
MAX9788
Chip Information
PROCESS: BiCMOS
MAX9788
14VP-P, Class G Ceramic Speaker Driver
______________________________________________________________________________________ 13
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
24L QFN THIN.EPS
PACKAGE OUTLINE,
21-0139
2
1
E
12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
MAX9788
14VP-P, Class G Ceramic Speaker Driver
14 ______________________________________________________________________________________
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE,
21-0139
2
2
E
12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
MAX9788
14VP-P, Class G Ceramic Speaker Driver
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________
15
© 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
5x4 UCSP.EPS
WHAT'S NEW
PRODUCTS
SOLUTIONS
DESIGN
APPNOTES
SUPPORT
BUY
COMPANY
MEMBERS
MAX9788
Part Number Table
Notes:
See the MAX9788 QuickView Data Sheet for further information on this product family or download the
MAX9788 full data sheet (PDF, 300kB).
1.
Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.2.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within
one business day.
3.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: See full
data sheet or Part Naming Conventions.
4.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the
product uses.
5.
Part Number
Free
Sample
Buy
Direct
Package:
TYPE PINS SIZE
DRAWING CODE/VAR *
Temp
RoHS/Lead-Free?
Materials Analysis
MAX9788ETI+
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+T
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+C6F
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+T
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
Didn't Find What You Need?
CONTACT US: SEND US AN EMAIL
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WHAT'S NEW
PRODUCTS
SOLUTIONS
DESIGN
APPNOTES
SUPPORT
BUY
COMPANY
MEMBERS
MAX9788
Part Number Table
Notes:
See the MAX9788 QuickView Data Sheet for further information on this product family or download the
MAX9788 full data sheet (PDF, 300kB).
1.
Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.2.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within
one business day.
3.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: See full
data sheet or Part Naming Conventions.
4.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the
product uses.
5.
Part Number
Free
Sample
Buy
Direct
Package:
TYPE PINS SIZE
DRAWING CODE/VAR *
Temp
RoHS/Lead-Free?
Materials Analysis
MAX9788ETI+
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+T
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+C6F
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+T
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
Didn't Find What You Need?
CONTACT US: SEND US AN EMAIL
C opyright 2007 by Maxim I ntegrated P roducts, Dallas Semiconduc tor • Legal Notices • Privacy P olicy
WHAT'S NEW
PRODUCTS
SOLUTIONS
DESIGN
APPNOTES
SUPPORT
BUY
COMPANY
MEMBERS
MAX9788
Part Number Table
Notes:
See the MAX9788 QuickView Data Sheet for further information on this product family or download the
MAX9788 full data sheet (PDF, 300kB).
1.
Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.2.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within
one business day.
3.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: See full
data sheet or Part Naming Conventions.
4.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the
product uses.
5.
Part Number
Free
Sample
Buy
Direct
Package:
TYPE PINS SIZE
DRAWING CODE/VAR *
Temp
RoHS/Lead-Free?
Materials Analysis
MAX9788ETI+
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+T
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+C6F
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+T
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
Didn't Find What You Need?
CONTACT US: SEND US AN EMAIL
C opyright 2007 by Maxim I ntegrated P roducts, Dallas Semiconduc tor • Legal Notices • Privacy P olicy
WHAT'S NEW
PRODUCTS
SOLUTIONS
DESIGN
APPNOTES
SUPPORT
BUY
COMPANY
MEMBERS
MAX9788
Part Number Table
Notes:
See the MAX9788 QuickView Data Sheet for further information on this product family or download the
MAX9788 full data sheet (PDF, 300kB).
1.
Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.2.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within
one business day.
3.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: See full
data sheet or Part Naming Conventions.
4.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the
product uses.
5.
Part Number
Free
Sample
Buy
Direct
Package:
TYPE PINS SIZE
DRAWING CODE/VAR *
Temp
RoHS/Lead-Free?
Materials Analysis
MAX9788ETI+
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+T
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788ETI+C6F
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9788EBP+T
UC SP;18 pin;
Dwg: 21-0095J (PDF)
Use pkgcode/variation: B20+7*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
Didn't Find What You Need?
CONTACT US: SEND US AN EMAIL
C opyright 2007 by Maxim I ntegrated P roducts, Dallas Semiconduc tor • Legal Notices • Privacy P olicy