MAX9787ETI [MAXIM]

2.2W Stereo Audio Power Amplifier with Analog Volume Control; 2.2W立体声音频功率放大器与模拟音量控制
MAX9787ETI
型号: MAX9787ETI
厂家: MAXIM INTEGRATED PRODUCTS    MAXIM INTEGRATED PRODUCTS
描述:

2.2W Stereo Audio Power Amplifier with Analog Volume Control
2.2W立体声音频功率放大器与模拟音量控制

放大器 功率放大器
文件: 总15页 (文件大小:235K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
19-3882; Rev 0; 10/05  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
General Description  
Features  
Class AB, 2.2W, Stereo BTL Speaker Amplifiers  
Analog Volume Control  
The MAX9787 combines a stereo, 2.2W audio power  
amplifier with an analog volume control in a single device.  
A high 90dB PSRR and low 0.01% THD+N ensures clean,  
low-distortion amplification of the audio signal.  
BEEP Input with Glitch Filter  
5V Single-Supply Operation  
The analog volume control can be driven with a poten-  
tiometer, an RC-filtered PWM source, or a DAC output.  
A BEEP input allows the addition of alert signals from  
the controller to the audio path.  
High 90dB PSRR  
Low-Power Shutdown Mode  
Industry-Leading Click-and-Pop Suppression  
Low 0.01% THD+N at 1kHz  
Industry-leading, click-and-pop suppression eliminates  
audible transients during power and shutdown cycles.  
Other features include single-supply voltage, a shut-  
down mode, logic-selectable gain, thermal-overload,  
and output short-circuit protection.  
Short-Circuit and Thermal Protection  
Selectable-Gain Settings  
Space-Saving 28-Pin TQFN (5mm x 5mm x 0.8mm)  
The MAX9787 is offered in a space-saving, thermally  
efficient, 28-pin, thin QFN (5mm x 5mm x 0.8mm) pack-  
age, and is specified over the extended -40°C to +85°C  
temperature range.  
Applications  
Ordering Information  
Portable DVD Players  
Notebook PCs  
Flat-Panel TVs  
Tablet PCs  
PART  
PIN-PACKAGE  
PKG CODE  
LCD Projectors  
MAX9787ETI+  
28 TQFN-EP*  
T2855N-1  
Multimedia Monitors  
Note: This device is specified for -40°C to +85°C operation.  
+Denotes lead-free package.  
*EP = Exposed paddle.  
PC Displays  
Typical Operating Circuit  
Pin Configuration  
TOP VIEW  
+5V  
21 20  
19 18  
17 16  
15  
SHDN 22  
GAIN2 23  
GAIN1 24  
14 N.C.  
13 N.C.  
Σ
12  
V
SS  
MAX9787  
V
25  
11 CPV  
10 C1N  
DD  
SS  
Σ
GND 26  
INR 27  
VOL 28  
9
8
CPGND  
C1P  
BEEP  
*EP  
MAX9787  
VOLUME  
+
1
2
3
4
5
6
7
THIN QFN  
*EXPOSED PAD.  
________________________________________________________________ Maxim Integrated Products  
1
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.  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
ABSOLUTE MAXIMUM RATINGS  
Supply Voltage (V , PV , CPV to GND) .......................+6V  
Continuous Input Current (all other pins) ......................... 20mA  
DD  
DD  
DD  
GND to PGND..................................................................... 0.ꢀV  
Continuous Power Dissipation (T = +70°C)  
A
CPV , C1N, V to GND .........................-6.0V to (GND + 0.ꢀV)  
28-Pin Thin QFN (derate 2ꢀ.8mW/°C above +70°C) .......1.9W  
Junction Temperature......................................................+150°C  
Operating Temperature Range ...........................-40°C to +85°C  
Storage Temperature Range.............................-65°C to +150°C  
Lead Temperature (soldering, 10s) .................................+ꢀ00°C  
SS  
SS  
Any Other Pin .............................................-0.ꢀV to (V  
+ 0.ꢀV)  
DD  
Duration of OUT_ Short Circuit to GND or PV ........Continuous  
DD  
Duration of OUT_+ Short Circuit to OUT_-.................Continuous  
Continuous Current (PV , OUT_, PGND) ...........................1.7A  
DD  
Continuous Current (CPV , C1N, C1P, CPV  
V
)......850mA  
DD  
SS, SS  
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  
= PV  
= CPV  
= 5V, GND = PGND = CPGND = 0V, SHDN = V , C  
= 1µF, C1 = C2 = 1µF, speaker load  
BIAS  
DD  
DD  
DD  
DD  
terminated between OUT_+ and OUT_-, GAIN1 = GAIN2 = VOL = 0V, T = T  
to T  
, unless otherwise noted. Typical values are  
A
MIN  
MAX  
at T = +25°C.) (Note 1)  
A
PARAMETER  
GENERAL  
SYMBOL  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
Supply Voltage Range  
Quiescent Supply Current  
Shutdown Supply Current  
Bias Voltage  
V
, PV  
Inferred from PSRR test  
4.5  
5.5  
29  
5
V
mA  
µA  
V
DD  
DD  
I
14  
0.2  
1.8  
10  
DD  
I
SHDN = GND  
SHDN  
V
1.7  
10  
1.9  
BIAS  
Switching Time  
t
Gain or input switching  
Amplifier inputs (Note 2)  
µs  
k  
ms  
SW  
Input Resistance  
R
20  
ꢀ0  
6
IN  
Turn-On Time  
t
25  
SON  
Measured between OUT_+ and OUT_-,  
= +25°C  
Output Offset Voltage  
V
0.4  
mV  
OS  
T
A
PV  
or V  
= 4.5V to 5.5V (T = +25°C)  
75  
90  
80  
DD  
DD  
A
Power-Supply Rejection Ratio  
(Note ꢀ)  
PSRR  
f = 1kHz, V  
= 200mV  
RIPPLE P-P  
dB  
f = 10kHz, V  
= 200mV  
55  
RIPPLE  
P-P  
R = 8Ω  
0.65  
1.2  
0.8  
1.5  
2.2  
0.01  
0.02  
L
THD+N = 1%,  
f = 1kHz,  
Output Power (Note 4)  
P
W
%
R = 4Ω  
L
OUT  
T
A
= +25°C  
R = Ω  
L
R = 8, P  
= 500mW, f = 1kHz  
= 1W, f = 1kHz  
L
OUT  
Total Harmonic Distortion Plus  
Noise  
THD+N  
R = 4, P  
L
OUT  
2
_______________________________________________________________________________________  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
ELECTRICAL CHARACTERISTICS (continued)  
(V  
= PV  
= CPV  
= 5V, GND = PGND = CPGND = 0V, SHDN = V , C  
= 1µF, C1 = C2 = 1µF, speaker load  
BIAS  
DD  
DD  
DD  
DD  
terminated between OUT_+ and OUT_-, GAIN1 = GAIN2 = VOL = 0V, T = T  
to T  
, unless otherwise noted. Typical values are  
A
MIN  
MAX  
at T = +25°C.) (Note 1)  
A
PARAMETER  
SYMBOL  
CONDITIONS  
= 500mW, BW = 22Hz to  
OUT  
MIN  
TYP  
MAX  
UNITS  
R = 8, P  
22kHz  
L
Signal-to-Noise Ratio  
SNR  
90  
dB  
Noise  
V
BW = 22Hz to 22kHz, A-weighted  
No sustained oscillations  
80  
200  
75  
µV  
RMS  
n
Capacitive-Load Drive  
Crosstalk  
C
pF  
dB  
L
L to R, R to L, f = 10kHz  
Slew Rate  
SR  
1.4  
6
V/µs  
GAIN1 = 0, GAIN2 = 0  
GAIN1 = 1, GAIN2 = 0  
GAIN1 = 0, GAIN2 = 1  
GAIN1 = 1, GAIN2 = 1  
7.5  
9
Gain (Maximum Volume Setting)  
A
dB  
VMAX(SPKR)  
10.5  
CHARGE PUMP  
Charge-Pump Frequency  
VOLUME CONTROL  
VOL Input Impedance  
VOL Input Hysteresis  
Full-Mute Input Voltage  
Channel Matching  
f
500  
550  
600  
kHz  
OSC  
R
100  
10  
MΩ  
mV  
V
VOL  
(Note 5)  
4.29  
0.2  
A = -25dB to +1ꢀ.5dB  
V
dB  
BEEP INPUT  
Beep Signal Minimum Amplitude  
Beep Signal Minimum Frequency  
V
R
B
= ꢀꢀk(Note 6)  
0.ꢀ  
V
P-P  
BEEP  
f
ꢀ00  
Hz  
BEEP  
LOGIC INPUT (SHDN, GAIN1, GAIN2, VOL)  
Logic Input High Voltage  
Logic Input Low Voltage  
Logic Input Current  
V
2
V
V
IH  
V
0.8  
1
IL  
I
µA  
IN  
Note 1: All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.  
Note 2: Guaranteed by design. Not production tested.  
Note 3: PSRR is specified with the amplifier input connected to GND through C  
.
IN  
Note 4: Output power levels are measured with the thin QFN’s exposed paddle soldered to the ground plane.  
Note 5: See Table ꢀ for details of the mute levels.  
Note 6: The value of R dictates the minimum beep signal amplitude (see the BEEP Input section).  
B
_______________________________________________________________________________________  
3
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
Typical Operating Characteristics  
(Measurement BW = 22Hz to 22kHz, T = +25°C, unless otherwise noted.)  
A
TOTAL HARMONIC DISTORTION PLUS NOISE  
vs. FREQUENCY  
TOTAL HARMONIC DISTORTION PLUS NOISE  
vs. FREQUENCY  
TOTAL HARMONIC DISTORTION PLUS NOISE  
vs. FREQUENCY  
10  
1
10  
1
10  
1
V
= 5V  
V
= 5V  
V
= 5V  
CC  
CC  
CC  
R = 3  
R = 4Ω  
R = 8Ω  
L
L
L
A
V
= 10.5dB  
A
= 10.5dB  
A = 10.5dB  
V
V
OUTPUT POWER = 1.5W  
OUTPUT POWER = 1.25W  
OUTPUT POWER = 500mW  
OUTPUT POWER = 100mW  
0.1  
0.01  
0.1  
0.01  
0.1  
0.01  
OUTPUT POWER = 500mW  
OUTPUT POWER = 600mW  
0.001  
0.001  
0.001  
0.0001  
0.0001  
0.0001  
10  
100  
1k  
10k  
100k  
10  
100  
1k  
10k  
100k  
10  
100  
1k  
10k  
100k  
FREQUENCY (Hz)  
FREQUENCY (Hz)  
FREQUENCY (Hz)  
TOTAL HARMONIC DISTORTION PLUS NOISE  
vs. OUTPUT POWER  
TOTAL HARMONIC DISTORTION PLUS NOISE  
vs. OUTPUT POWER  
TOTAL HARMONIC DISTORTION PLUS NOISE  
vs. OUTPUT POWER  
100  
10  
1
100  
10  
1
100  
10  
1
V
= 5V  
V
= 5V  
CC  
L
CC  
L
V
V
= 5V  
CC  
L
V
R = 4Ω  
A
R = 8Ω  
A = 10.5dB  
V
R = 3Ω  
A
= 10.5dB  
= 10.5dB  
f
= 10kHz  
f
= 10kHz  
IN  
IN  
f
= 10kHz  
0.1  
0.1  
0.1  
IN  
0.01  
0.01  
0.01  
f
= 1kHz  
2.0  
f
= 1kHz  
IN  
IN  
f
= 20Hz  
f
= 1kHz  
0.8  
f
= 20Hz  
IN  
IN  
IN  
f
= 20Hz  
IN  
0.001  
0.001  
0.001  
0
0.5  
1.0  
1.5  
2.5  
3.0  
0
2.0  
0
1.2  
0.5  
1.0  
OUTPUT POWER (W)  
1.5  
0.2  
0.4  
0.6  
1.0  
OUTPUT POWER (W)  
OUTPUT POWER (W)  
POWER DISSIPATION vs. OUTPUT POWER  
OUTPUT POWER  
vs. LOAD RESISTANCE  
5
4
3
2
1
0
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
V
= 5V  
V
= 5V  
DD  
CC  
f = 1kHz  
= P  
f = 1kHz  
= 10.5dB  
P
+ P  
OUTR  
A
OUT  
OUTL  
V
R = 4Ω  
L
THD+N = 10%  
THD+N = 1%  
R = 8Ω  
L
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0  
OUTPUT POWER (W)  
1
10  
LOAD RESISTANCE ()  
100  
4
_______________________________________________________________________________________  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
Typical Operating Characteristics (continued)  
(Measurement BW = 22Hz to 22kHz, T = +25°C, unless otherwise noted.)  
A
POWER-SUPPLY REJECTION RATIO  
vs. FREQUENCY  
CROSSTALK vs. FREQUENCY  
0
-10  
-20  
-30  
-40  
-50  
-60  
-70  
-80  
-90  
-100  
0
V
A
= 200mV  
P-P  
= 10.5dB  
V
V
= 5V  
RIPPLE  
V
CC  
-10  
-20  
-30  
-40  
-50  
-60  
-70  
-80  
= 200mV  
RIPPLE  
P-P  
OUTPUT REFERRED  
R = 4Ω  
L
LEFT TO RIGHT  
-90  
-100  
-110  
-120  
RIGHT TO LEFT  
10  
100  
1k  
FREQUENCY (Hz)  
10k  
100k  
10  
100  
1k  
10k  
100k  
FREQUENCY (Hz)  
TURN-ON RESPONSE  
TURN-OFF RESPONSE  
MAX9787 toc11  
MAX9787 toc12  
5V/div  
5V/div  
SHDN  
SHDN  
OUT_+  
AND  
OUT_+  
AND  
2V/div  
2V/div  
OUT_-  
OUT_-  
OUT_+  
- OUT_-  
OUT_+  
- OUT_-  
100mV/div  
20mV/div  
R
= 8Ω  
R
= 8Ω  
L
L
20ms/div  
20ms/div  
SHUTDOWN SUPPLY CURRENT  
vs. SUPPLY VOLTAGE  
SUPPLY CURRENT  
vs. SUPPLY VOLTAGE  
0.35  
0.30  
0.25  
0.20  
0.15  
0.10  
0.05  
0
18  
16  
14  
12  
10  
8
6
4
2
0
4.50  
4.75  
5.00  
5.25  
5.50  
4.50  
4.75  
5.00  
5.25  
5.50  
SUPPLY VOLTAGE (V)  
SUPPLY VOLTAGE (V)  
_______________________________________________________________________________________  
5
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
Pin Description  
PIN  
NAME  
FUNCTION  
1
2
INL  
Left-Channel Audio Input  
BEEP  
Audible Alert Beep Input  
ꢀ, 19  
4
PGND  
OUTL+  
OUTL-  
Power Ground  
Left-Channel Positive Speaker Output  
Left-Channel Negative Speaker Output  
Speaker Amplifier Power Supply  
Charge-Pump Power Supply  
5
6, 15, 16  
7
PV  
DD  
CPV  
DD  
8
C1P  
Charge-Pump Flying-Capacitor Positive Terminal  
Charge-Pump Ground  
9
CPGND  
C1N  
10  
Charge-Pump Flying-Capacitor Negative Terminal  
11  
CPV  
Charge-Pump Output. Connect to V  
.
SS  
SS  
12  
V
SS  
Amplifier Negative Power Supply  
1ꢀ, 14  
17  
N.C.  
OUTR-  
OUTR+  
GND  
No Connection. Not internally connected.  
Right-Channel Negative Speaker Output  
Right-Channel Positive Speaker Output  
Ground  
18  
20, 26  
21  
BIAS  
Common-Mode Bias Voltage. Bypass with a 1µF capacitor to GND.  
22  
SHDN  
GAIN2  
GAIN1  
Shutdown. Drive SHDN low to disable the device. Connect SHDN to V  
Gain Control Input 2  
for normal operation.  
DD  
2ꢀ  
24  
Gain Control Input 1  
25  
V
Power Supply  
DD  
27  
INR  
VOL  
EP  
Right-Channel Audio Input  
28  
Analog Volume Control Input  
Exposed Pad. Connect to GND.  
EP  
6
_______________________________________________________________________________________  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
required, additional high-frequency ripple attenuation  
Detailed Description  
can be achieved by increasing the size of C2 (see the  
The MAX9787 combines a 2.2W bridge-tied load (BTL)  
speaker amplifier and an analog volume control, BEEP  
input, and four-level gain control. The MAX9787 features  
high 90dB, low 0.01% THD+N, industry-leading click-  
pop performance, and a low-power shutdown mode.  
Typical Operating Circuit).  
BIAS  
The MAX9787 features 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.  
Choose the value of the bypass capacitor as described  
in the BIAS Capacitor section. No external load should  
be applied to BIAS. Any load lowers the BIAS voltage,  
affecting the overall performance of the device.  
Each signal path consists of an input amplifier that sets  
the gain of the signal path, and feeds the speaker  
amplifier (Figure 1). The speaker amplifier uses a 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 magni-  
tude, but 180o out of phase.  
Gain Selection  
The GAIN1 and GAIN2 inputs set the maximum gain of  
the speaker and amplifiers (Table 1). The gain of the  
device can vary based upon the voltage at VOL (see  
the Analog Volume Control section). However, the max-  
imum gain cannot be exceeded.  
An analog volume control varies the gain of the ampli-  
fiers based on the DC voltage applied at VOL. An under-  
voltage lockout prevents operation from an insufficient  
power supply. Click-and-pop suppression eliminates  
audible transients on startup and shutdown. The ampli-  
fiers include thermal-overload and short-circuit protec-  
tion. An additional feature of the speaker amplifiers is  
that there is no phase inversion from input to output.  
Analog Volume Control (VOL)  
An analog volume control varies the gain of the device  
in ꢀ1 discrete steps based upon the DC voltage  
Charge Pump  
The MAX9787 features 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 turn-on and turn-off  
transients. Limiting the switching speed of the charge  
pump minimizes the di/dt noise caused by the parasitic  
bond wire and trace inductance. Although not typically  
applied to VOL. The input range of V  
is from 0 (full  
VOL  
volume) to 0.858 x PV  
(full mute), with example step  
DD  
sizes shown in Table 2. Connect the reference of the  
device driving VOL (Figure 2) to PV . Since the vol-  
DD  
ume control ADC is ratiometric to PV , any changes in  
DD  
Table 1. Gain Settings  
SPEAKER MODE  
GAIN2  
GAIN1  
GAIN (dB)  
0
0
1
1
0
1
0
1
6
7.5  
9
IN_  
10.5  
OUT_+  
BIAS  
BIAS  
MAX9787  
PV  
DD  
VOLUME  
OUT_  
V
REF  
VOL  
CONTROL  
DAC  
VOL  
BIAS  
Figure 1. MAX9787 Signal Path  
Figure 2. Volume Control Circuit  
_______________________________________________________________________________________  
7
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
Table 2. Volume Levels  
V
(V)  
SPEAKER MODE GAIN (dB)  
VOL  
GAIN1 = 0,  
GAIN2 = 0  
GAIN1 = 1,  
GAIN2 = 0  
GAIN1 = 0,  
GAIN2 = 1  
GAIN1 = 1,  
GAIN2 = 1  
V
*
V
*
V
*
MIN  
TYP  
MAX  
0
0.ꢀ70  
0.800  
0.915  
1.0ꢀ5  
1.150  
1.265  
1.ꢀ85  
1.500  
1.620  
1.7ꢀ5  
1.855  
1.970  
2.090  
2.205  
2.ꢀ20  
2.440  
2.555  
2.675  
2.790  
2.910  
ꢀ.025  
ꢀ.140  
ꢀ.260  
ꢀ.ꢀ75  
ꢀ.495  
ꢀ.610  
ꢀ.7ꢀ0  
ꢀ.845  
ꢀ.965  
4.080  
4.195  
4.290  
0.742  
0.860  
0.977  
1.094  
1.211  
1.ꢀ28  
1.446  
1.56ꢀ  
1.680  
1.797  
1.914  
2.0ꢀ2  
2.149  
2.266  
2.ꢀ8ꢀ  
2.500  
2.617  
2.7ꢀ5  
2.852  
2.969  
ꢀ.086  
ꢀ.20ꢀ  
ꢀ.ꢀ21  
ꢀ.4ꢀ8  
ꢀ.555  
ꢀ.672  
ꢀ.789  
ꢀ.907  
4.024  
4.141  
4.258  
5.000  
6
5
7.5  
7
9
8.5  
8
10.5  
10  
9.5  
9
0.742  
0.860  
0.977  
1.094  
1.211  
1.ꢀ28  
1.446  
1.56ꢀ  
1.680  
1.797  
1.914  
2.0ꢀ2  
2.149  
2.266  
2.ꢀ8ꢀ  
2.500  
2.617  
2.7ꢀ5  
2.852  
2.969  
ꢀ.086  
ꢀ.20ꢀ  
ꢀ.ꢀ21  
ꢀ.4ꢀ8  
ꢀ.555  
ꢀ.672  
ꢀ.789  
ꢀ.907  
4.024  
4.141  
4.258  
4
6
5
7.5  
7
1
4
8.5  
8
-1  
6
-ꢀ  
1
5
7.5  
7
-5  
-1  
4
-7  
-ꢀ  
6
-9  
-5  
1
5
-11  
-1ꢀ  
-15  
-17  
-19  
-21  
-2ꢀ  
-25  
-27  
-29  
-ꢀ1  
-ꢀꢀ  
-ꢀ5  
-ꢀ7  
-41  
-45  
-48  
-5ꢀ  
-57  
-61  
-65  
MUTE  
-7  
-1  
4
-9  
-ꢀ  
-11  
-1ꢀ  
-15  
-17  
-19  
-21  
-2ꢀ  
-25  
-27  
-29  
-ꢀ1  
-ꢀ  
-5  
1
-7  
-1  
-9  
-ꢀ  
-11  
-1ꢀ  
-15  
-17  
-9  
-5  
-7  
-9  
-11  
-1ꢀ  
-15  
-17  
-19  
-21  
-2ꢀ  
-25  
-27  
-29  
-ꢀ1  
-ꢀꢀ  
-ꢀ5  
MUTE  
-21  
-2ꢀ  
-2  
-27  
-29  
-ꢀ1  
-ꢀꢀ  
-ꢀ5  
-ꢀ7  
-41  
-45  
MUTE  
-ꢀ5  
-ꢀ7  
-41  
-45  
-49  
-5ꢀ  
-57  
MUTE  
*Based on PV = 5V  
DD  
8
_______________________________________________________________________________________  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
PV  
are negated. The gain step sizes are not con-  
roughly the amplitude of V  
times the gain of  
BEEP(OUT)  
DD  
stant; the step sizes are 0.5dB/step at the upper  
extreme, 2dB/step in the midrange, and 4dB/step at the  
lower extreme. Figure ꢀ shows the transfer function of  
the volume control for a 5V supply.  
the selected signal path.  
The input resistor (R ) sets the gain of the BEEP input  
B
amplifier, and thus the amplitude of V  
.
BEEP(OUT)  
Choose R based on:  
B
BEEP Input  
An audible alert beep input (BEEP) accepts a mono  
system alert signal and mixes it into the stereo audio  
V
x R  
0.ꢀ  
IN  
INT  
R
B
path. When the amplitude of V  
exceeds  
BEEP(OUT)  
where R  
is the value of the BEEP amplifier feedback  
800mV  
(Figure 4) and the frequency of the beep sig-  
INT  
P-P  
resistor (47k) and V is the BEEP input amplitude.  
nal is greater than 400Hz, the beep signal is mixed into  
the active audio path (speaker or headphone). If the  
IN  
Note that the BEEP amplifier can be set up as either an  
attenuator, if the original alert signal amplitude is too  
large, or set to gain up the alert signal if it is below  
signal at V  
is either < 800mV  
or <400Hz,  
BEEP(OUT)  
P-P  
the BEEP signal is not mixed into the audio path. The  
amplitude of the BEEP signal at the device output is  
800mV . AC-couple the alert signal to BEEP. Choose  
P-P  
the value of the coupling capacitor as described in the  
Input Filtering section. Multiple beep inputs can be  
summed (Figure 4).  
VOLUME CONTROL  
TRANSFER FUNCTION  
20  
Shutdown  
The MAX9787 features a 0.2µA, low-power shutdown  
mode that reduces quiescent current consumption and  
extends battery life. Driving SHDN low disables the  
drive amplifiers, bias circuitry, and charge pump, and  
drives BIAS and all outputs to GND. Connect SHDN to  
GAIN1 = GAIN2 = 0  
10  
0
AUDIO  
TAPER POT  
-10  
-20  
-30  
-40  
-50  
-60  
-70  
-80  
V
for normal operation.  
DD  
MAX9787  
Click-and-Pop Suppression  
The MAX9787 speaker amplifiers feature 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. When entering shutdown, both ampli-  
fier outputs ramp to GND quickly and simultaneously.  
0
1
2
3
4
5
V
(V)  
VOL  
Figure 3. Volume Control Transfer Function  
R
S1  
0.47µF  
0.47µF  
0.47µF  
47kΩ  
R
INT  
SOURCE 1  
SOURCE 2  
SOURCE 3  
47kΩ  
R
S2  
47kΩ  
SPEAKER AMPLIFIER  
BEEP  
V
OUT(BEEP)  
WINDOW  
INPUTS  
R
S3  
47kΩ  
DETECTOR  
(0.3V THRESHOLD)  
P-P  
MAX9787  
FREQUENCY  
DETECTOR  
BIAS  
(300Hz THRESHOLD)  
Figure 4. Beep Input  
_______________________________________________________________________________________  
9
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
Power Dissipation and Heat Sinking  
Applications Information  
Under normal operating conditions, the MAX9787 can dis-  
sipate a significant amount of power. The maximum power  
dissipation for each package is given in the Absolute  
Maximum Ratings under Continuous Power Dissipation, or  
can be calculated by the following equation:  
BTL Speaker Amplifiers  
The MAX9787 features 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 single-ended configuration,  
where one side of the load is connected to ground.  
Driving the load differentially doubles the output volt-  
age compared to a single-ended amplifier under similar  
conditions. Thus, the device’s differential gain is twice  
the closed-loop gain of the input amplifier. The effective  
gain is given by:  
T
T  
A
J(MAX)  
P
=
DISSPKG(MAX)  
θ
JA  
where TJ(MAX) is +150°C, TA is the ambient temperature,  
o
and θJA is the reciprocal of the derating factor in C/W  
as specified in the Absolute Maximum Ratings section.  
For example, θJA of the TQFN package is +42oC/W. For  
optimum power dissipation, the exposed paddle of the  
package should be connected to the ground plane  
(see the Layout and Grounding section).  
R
F
A
= 2×  
VD  
R
IN  
Substituting 2 X VOUT(P-P) into the following equation  
yields four times the output power due to double the  
output voltage:  
For 8applications, the worst-case power dissipation  
occurs when the output power is 1.1W/channel, result-  
ing in a power dissipation of about 1W. In this case, the  
TQFN packages can be used without violating the max-  
imum power dissipation or exceeding the thermal pro-  
tection threshold.  
V
OUT(PP)  
V
=
=
RMS  
2 2  
2
V
RMS  
Output Power  
The increase in power delivered by the BTL configura-  
tion directly results in an increase in internal power dis-  
sipation over the single-ended configuration.  
P
OUT  
R
L
Since the differential outputs are biased at midsupply,  
there is no net DC voltage across the load. This elimi-  
nates the need for DC-blocking capacitors required for  
single-ended amplifiers. These capacitors can be large  
and expensive, can consume board space, and can  
degrade low-frequency performance.  
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 heatsinking to the device.  
Large output, supply, and ground PC board traces  
improve the maximum power dissipation in the package.  
1000  
V
= 5V  
DD  
R = 16Ω  
V
L
100  
10  
A
= 3dB  
V
+1  
-1  
OUT(P-P)  
OUTPUTS IN PHASE  
1
2 x V  
V
OUT(P-P)  
0.1  
0.01  
0.001  
OUT(P-P)  
OUTPUTS 180° OUT OF PHASE  
0
25  
50  
75  
100  
125  
150  
OUTPUT POWER (mW)  
Figure 5. Bridge-Tied Load Configuration  
Figure 6. Total Harmonic Distortion Plus Noise vs. Output Power  
with Inputs In/Out of Phase  
10 ______________________________________________________________________________________  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
Table 3. Suggested Capacitor Manufacturers  
SUPPLIER  
Taiyo Yuden  
TDK  
PHONE  
FAX  
WEBSITE  
www.t-yuden.com  
www.component.tdk.com  
800-ꢀ48-2496  
807-80ꢀ-6100  
847-925-0899  
847-ꢀ90-4405  
Thermal-overload protection limits total power dissipa-  
tion in these devices. When the junction temperature  
exceeds +160°C, the thermal-protection circuitry dis-  
ables the amplifier output stage. The amplifiers are  
enabled once the junction temperature cools by 15°C.  
This results in a pulsing output under continuous ther-  
mal-overload conditions as the device heats and cools.  
BIAS Capacitor  
BIAS is the output of the internally generated DC bias  
voltage. The BIAS bypass capacitor, CBIAS, 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 amplifiers. Bypass  
BIAS with a 1µF capacitor to GND.  
Power Supplies  
The MAX9787 speaker amplifiers are powered from  
PVDD. PVDD ranges from 4.5V to 5.5V. VSS is the nega-  
tive supply of the amplifiers. Connect VSS to CPVSS. The  
charge pump is powered by CPVDD. CPVDD should be  
the same potential as PVDD. The charge pump inverts  
the voltage at CPVDD, and the resulting voltage  
appears at CPVSS. The remainder of the device is pow-  
Charge-Pump Capacitor Selection  
Use capacitors with an ESR less than 100mfor 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. Table 4  
lists suggested manufacturers.  
ered by VDD  
.
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. Increasing the value of C1 improves  
load regulation and reduces the charge-pump output  
resistance to an extent. See the Output Power vs.  
Charge-Pump Capacitance and Load Resistance  
graph in the Typical Operating Characteristics. Above  
2.2µF, the on-resistance of the switches and the ESR of  
C1 and C2 dominate.  
Component Selection  
Input Filtering  
The input capacitor (CIN), in conjunction with the ampli-  
fier input resistance (RIN), forms a highpass filter that  
removes the DC bias from an incoming signal (see the  
Typical Operating Circuit). The AC-coupling capacitor  
allows the amplifier to bias the signal to an optimum DC  
level. Assuming zero source impedance, the -ꢀdB point  
of the highpass filter is given by:  
1
f
=
ꢀdB  
2πR C  
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. See the Output Power  
vs. Charge-Pump Capacitance and Load Resistance  
graph in the Typical Operating Characteristics.  
IN IN  
RIN is the amplifier’s internal input resistance value  
given in the Electrical Characteristics. Choose CIN such  
that f  
is well below the lowest frequency of interest.  
-ꢀdB  
Setting f  
too high affects the amplifier’s low-fre-  
-ꢀdB  
quency response. Use capacitors with low-voltage  
coefficient dielectrics, such as tantalum or aluminum  
electrolytic. Capacitors with high-voltage coefficients,  
such as ceramics, may result in increased distortion at  
low frequencies.  
______________________________________________________________________________________ 11  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
CPVDD Bypass Capacitor  
The CPVDD bypass capacitor (Cꢀ) lowers the output  
impedance of the power supply and reduces the  
impact of the MAX9787’s charge-pump switching tran-  
sients. Bypass CPVDD with Cꢀ, the same value as C1,  
and place it physically close to the CPVDD and PGND  
(refer to the MAX9750 Evaluation Kit for a suggested  
layout).  
audio signal. Connect CPGND, PGND, and GND  
together at a single point on the PC board. Route  
CPGND and all traces that carry switching transients  
away from GND, PGND, and the traces and compo-  
nents in the audio signal path.  
Connect all components associated with the charge  
pump (C2 and Cꢀ) to the CPGND plane. Connect VSS  
and CPVSS together at the device. Place the charge-  
pump capacitors (C1, C2, and Cꢀ) as close to the  
device as possible. Bypass PVDD with a 0.1µF capaci-  
tor to GND. Place the bypass capacitors as close to the  
device as possible.  
Powering Other Circuits  
from a Negative Supply  
An additional benefit of the MAX9787 is the internally  
generated negative supply voltage (CPVSS). CPVSS pro-  
vides the negative supply for the amplifiers. It can also  
be used to power other devices within a design.  
Current draw from CPVSS should be limited to 5mA;  
exceeding this affects the operation of the amplifier. A  
typical application is a negative supply to adjust the  
contrast of LCD modules.  
Use large, low-resistance output traces. As load imped-  
ance decreases, the current drawn from the device out-  
puts increase. At higher current, the resistance of the  
output traces decrease the power delivered to the load.  
For example, when compared to a 0trace, a 100mΩ  
trace reduces the power delivered to a 4load from  
2.1W to 2W. Large output, supply, and GND traces also  
improve the power dissipation of the device.  
When considering the use of CPVSS in this manner,  
note that the charge-pump voltage of CPVSS is roughly  
proportional to PVDD and is not a regulated voltage. The  
charge-pump output impedance plot appears in the  
Typical Operating Characteristics.  
The MAX9787 thin QFN features and exposed thermal  
pad on its underside. This pad lowers the package’s  
thermal resistance by providing a direct heat conduc-  
tion path from the die to the PC board. Connect the  
exposed thermal pad to GND by using a large pad and  
multiple vias to the GND plane.  
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 head away  
from the device. Good grounding improves audio per-  
formance, minimizes crosstalk between channels, and  
prevents any switching noise from coupling into the  
Chip Information  
TRANSISTOR COUNT: 9591  
PROCESS: BiCMOS  
12 ______________________________________________________________________________________  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
Block Diagram  
4.5V TO 5.5V  
0.1µF  
V
DD  
25  
6, 15, 16  
PV  
DD  
4.5V TO 5.5V  
0.1µF  
MAX9787  
C
1µF  
IN  
4
5
OUTL+  
OUTL-  
GAIN/  
VOLUME  
CONTROL  
INL  
1
BTL  
AMPLIFIER  
LEFT-CHANNEL  
AUDIO INPUT  
C
1µF  
IN  
18  
OUTR+  
GAIN/  
VOLUME  
CONTROL  
INR  
27  
21  
BTL  
AMPLIFIER  
RIGHT-CHANNEL  
AUDIO INPUT  
17 OUTR-  
BIAS  
C
BIAS  
1µF  
VOL 28  
24  
GAIN/  
VOLUME  
CONTROL  
GAIN1  
V
V
DD  
HEADPHONE  
DETECTION  
GAIN2 23  
DD  
1µF  
47kΩ  
BEEP  
DETECTION  
BEEP  
2
SHUTDOWN  
CONTROL  
SHDN  
22  
V
DD  
CPV  
DD  
7
3V TO 5.5V  
1µF  
C1P  
8
C1  
CHARGE  
PUMP  
1µF  
10  
C1N  
9
CPGND  
3, 19  
11  
CPV  
12  
20, 26  
GND  
V
PGND  
SS  
SS  
C2  
1µF  
______________________________________________________________________________________ 13  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
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.)  
D2  
D
b
0.10 M  
C A B  
C
L
D2/2  
D/2  
k
L
MARKING  
AAAAA  
E/2  
E2/2  
C
(NE-1) X  
e
L
E2  
E
PIN # 1 I.D.  
0.35x45°  
DETAIL A  
e/2  
PIN # 1  
I.D.  
e
(ND-1) X  
e
DETAIL B  
e
L
C
L
C
L
L1  
L
L
e
e
0.10  
C
A
0.08  
C
C
A3  
A1  
PACKAGE OUTLINE,  
16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm  
1
-DRAWING NOT TO SCALE-  
I
21-0140  
2
14 ______________________________________________________________________________________  
2.2W Stereo Audio Power Amplifier  
with Analog Volume Control  
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.)  
COMMON DIMENSIONS  
EXPOSED PAD VARIATIONS  
PKG.  
16L 5x5  
20L 5x5  
28L 5x5  
32L 5x5  
40L 5x5  
L
DOWN  
BONDS  
ALLOWED  
D2  
E2  
exceptions  
PKG.  
SYMBOL MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX.  
CODES  
±0.15  
MIN. NOM. MAX. MIN. NOM. MAX.  
3.00 3.10 3.20 3.00 3.10 3.20  
3.00 3.10 3.20 3.00 3.10 3.20  
A
0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80  
0.02 0.05 0.02 0.05 0.02 0.05 0.02 0.05 0.02 0.05  
0.20 REF. 0.20 REF. 0.20 REF. 0.20 REF. 0.20 REF.  
T1655-2  
T1655-3  
YES  
NO  
NO  
**  
**  
**  
**  
A1  
0
0
0
0
0
A3  
b
T1655N-1 3.00 3.10 3.20 3.00 3.10 3.20  
0.25 0.30 0.35 0.25 0.30 0.35 0.20 0.25 0.30 0.20 0.25 0.30 0.15 0.20 0.25  
4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10  
4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10  
T2055-3  
T2055-4  
3.00 3.10 3.20 3.00 3.10 3.20  
3.00 3.10 3.20 3.00 3.10 3.20  
YES  
NO  
D
E
**  
YES  
T2055-5  
T2855-3  
T2855-4  
T2855-5  
3.15 3.25 3.35 3.15 3.25 3.35 0.40  
e
0.80 BSC.  
0.25  
0.65 BSC.  
0.25  
0.50 BSC.  
0.25  
0.50 BSC.  
0.25  
0.40 BSC.  
3.15 3.25 3.35 3.15 3.25 3.35  
2.60 2.70 2.80 2.60 2.70 2.80  
2.60 2.70 2.80 2.60 2.70 2.80  
3.15 3.25 3.35 3.15 3.25 3.35  
YES  
YES  
NO  
**  
**  
**  
k
L
-
-
-
-
-
-
-
-
0.25 0.35 0.45  
0.30 0.40 0.50 0.45 0.55 0.65 0.45 0.55 0.65 0.30 0.40 0.50 0.40 0.50 0.60  
L1  
-
-
-
-
-
-
-
-
-
-
-
-
0.30 0.40 0.50  
NO  
YES  
YES  
T2855-6  
T2855-7  
**  
**  
N
ND  
NE  
16  
4
4
20  
5
5
28  
7
7
32  
8
8
40  
10  
10  
2.80  
2.60 2.70  
2.60 2.70 2.80  
T2855-8  
3.15 3.25 3.35 3.15 3.25 3.35 0.40  
WHHB  
WHHC  
WHHD-1  
WHHD-2  
-----  
JEDEC  
T2855N-1 3.15 3.25 3.35 3.15 3.25 3.35  
NO  
YES  
NO  
YES  
NO  
**  
**  
**  
**  
**  
**  
3.20  
3.00 3.10 .20  
T3255-3  
T3255-4  
T3255-5  
3.00 3.10  
3.00 3.10 3.20 3.00 3.10 .20  
3.20  
NOTES:  
3.00 3.10  
3.00 3.10 3.20  
1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994.  
2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.  
3. N IS THE TOTAL NUMBER OF TERMINALS.  
T3255N-1 3.00 3.10 3.20 3.00 3.10 3.20  
T4055-1 3.20 3.30 3.40 3.20 3.30 3.40  
YES  
**SEE COMMON DIMENSIONS TABLE  
4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL  
CONFORM TO JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE  
OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE TERMINAL #1  
IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE.  
5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN  
0.25 mm AND 0.30 mm FROM TERMINAL TIP.  
6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.  
7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.  
8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.  
9. DRAWING CONFORMS TO JEDEC MO220, EXCEPT EXPOSED PAD DIMENSION FOR  
T2855-3 AND T2855-6.  
10. WARPAGE SHALL NOT EXCEED 0.10 mm.  
11. MARKING IS FOR PACKAGE ORIENTATION REFERENCE ONLY.  
12. NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY.  
13. LEAD CENTERLINES TO BE AT TRUE POSITION AS DEFINED BY BASIC DIMENSION "e", ±0.05.  
PACKAGE OUTLINE,  
16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm  
2
-DRAWING NOT TO SCALE-  
21-0140  
I
2
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  
© 2005 Maxim Integrated Products  
Printed USA  
is a registered trademark of Maxim Integrated Products, Inc.  
Heaney  

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MAXIM

MAX9788EVKIT+

Delivers Greater than 14VP-P into a Ceramic Speaker
MAXIM

MAX9788EWP+TG45

14VP-P,Class G Ceramic Speaker Driver
MAXIM

MAX9788_07

14VP-P,Class G Ceramic Speaker Driver
MAXIM

MAX9788_V01

14VP-P,Class G Ceramic Speaker Driver
MAXIM