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19-3049; Rev 0; 10/03
ILABLE N KIT AVA EVALUATIO
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
General Description
The MAX9722A/MAX9722B stereo headphone amplifiers are designed for portable equipment where board space is at a premium. The MAX9722A/MAX9722B use a unique, patented DirectDrive architecture to produce a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, which saves cost, board space, and component height. Additionally, the gain of the amplifier is set internally (-2V/V, MAX9722B) or adjusted externally (MAX9722A). The MAX9722A/MAX9722B deliver up to 70mW per channel into a 16 load or 130mW into a 32 load and have low 0.009% THD+N. An 80dB at 217Hz power-supply rejection ratio (PSRR) allows these devices to operate from noisy digital supplies without an additional linear regulator. The MAX9722A/MAX9722B include 8kV ESD protection on the headphone outputs. Comprehensive anticlick-and-pop circuitry suppresses audible clicks and pops on startup and shutdown. A low-power shutdown mode reduces the supply current to 0.1A. The MAX9722A/MAX9722B operate from a single 2.4V to 5.5V supply, consume only 5.5mA of supply current, feature short-circuit and thermal-overload protection, and are specified over the extended -40C to +85C temperature range. The devices are available in tiny 16-pin thin QFN (3mm 3mm 0.8mm) and 16-pin TSSOP packages.
Features
o 2.4V to 5.5V Single-Supply Operation o High PSRR (80dB at 217Hz) Eliminates LDO o No Bulky DC-Blocking Capacitors Required o Ground-Referenced Outputs Eliminate DC Bias Voltage on Headphone Ground Pin o No Degradation of Low-Frequency Response Due to Output Capacitors o Differential Inputs for Enhanced Noise Cancellation o Adjustable Gain (MAX9722A) or Fixed -2V/V Gain (MAX9722B) o 130mW per Channel into 32 o Low 0.009% THD+N o Integrated Click-and-Pop Suppression o Low Quiescent Current (5.5mA) o Short-Circuit and Thermal-Overload Protection o 8kV ESD-Protected Amplifier Outputs (Human Body Model) o Available in a Space-Saving 16-Pin Thin QFN (3mm 3mm 0.8mm) Package
MAX9722A/MAX9722B
Applications
Notebook and Desktop PCs MP3 Players Flat-Panel Monitors Cellular Phones Smart Phones PDAs Portable Audio Equipment
Simplified Diagram
LEFT AUDIO INPUT
DirectDrive OUTPUTS ELIMINATE DC-BLOCKING CAPACITORS.
Ordering Information
PART TEMP RANGE PIN-PACKAGE 16 Thin QFN-EP* (3mm 3mm 0.8mm) 16 TSSOP 16 Thin QFN-EP* (3mm 3mm 0.8mm) 16 TSSOP TOP MARK AAX -- AAY --
RIGHT AUDIO INPUT FIXED GAIN ELIMINATES EXTERNAL RESISTOR NETWORK. SHDN
MAX9722B
MAX9722AETE -40C to +85C MAX9722AEUE -40C to +85C MAX9722BETE -40C to +85C MAX9722BEUE -40C to +85C
*EP = Exposed paddle.
Pin Configurations and Typical Operating Circuit appear at end of data sheet. 1
________________________________________________________________ Maxim Integrated Products
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.
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
ABSOLUTE MAXIMUM RATINGS
PGND to SGND .....................................................-0.3V to +0.3V PVDD and SVDD to PGND or SGND .........................-0.3V to +6V PVSS and SVSS to PGND..........................................+0.3V to -6V IN_ to SGND ................................(SVSS - 0.3V) to (SVDD + 0.3V) OUT_ to PGND ......................................................-3.0V to +3.0V SHDN to SGND..........................(SGND - 0.3V) to (SVDD + 0.3V) C1P to PGND ...........................................-0.3V to (PVDD + 0.3V) C1N to PGND............................................(SVSS - 0.3V) to +0.3V PVDD to SVDD ...........................................................................0V PVSS to SVSS ............................................................................0V Output Short Circuit to GND.......................................Continuous Continuous Power Dissipation (TA = +70C) 16-Pin Thin QFN (derate 14.7mW/C above +70C)....1176mW 16-Pin TSSOP (derate 9.4mW/C above +70C) .........755mW Junction Temperature ......................................................+150C Operating Temperature Range............................-40C to +85C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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
(PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1F, RL = , resistive load referenced to ground, for MAX9722A gain = -1V/V (RIN = RF = 10k), for MAX9722B gain = -2V/V (internally set), TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER GENERAL Supply Voltage Range Quiescent Supply Current Shutdown Supply Current SHDN Input Logic High SHDN Input Logic Low SHDN Input Leakage Current SHDN to Full Operation Time AMPLIFIERS Voltage Gain Gain Matching Input Offset Voltage Input Bias Current Input Impedance Input Common-Mode Voltage Range Common-Mode Rejection Ratio Power-Supply Rejection Ratio (Note 3) Output Power Output Voltage Output Impedance in Shutdown VIS IBIAS RIN VCM CMRR PSRR Input referred, MAX9722A, TA = +25C DC, VDD = 2.4V to 5.5V, input referred f = 217Hz, 100mVP-P ripple, input referred f = 10kHz, 100mVP-P ripple, input referred POUT VOUT RL = 16, THD+N = 1%, TA = +25C RL = 32, THD+N = 1%, TA = +25C RL = 1k 60 AV MAX9722B (Note 2) MAX9722B, between the right and left channels Between IN_+ and IN_-, AC-coupled (MAX9722A) Between IN_+ and IN_-, AC-coupled (MAX9722B) IN_+ and IN_MAX9722B, measured at IN_ 10 -0.5 -60 -80 -70 -90 -80 -50 70 130 2 10 mW VRMS k dB -1.98 -2 2 0.5 1.5 50 14.4 20 +0.7 2.5 5 -2.02 V/V % mV nA k V dB tSON VDD IDD ISHDN VIH VIL -1 +0.05 80 Guaranteed by PSRR test RL = SHDN = SGND 2 0.8 +1 2.4 5.5 0.1 5.5 13 2 V mA A V V A s SYMBOL CONDITIONS MIN TYP MAX UNITS
2
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5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
ELECTRICAL CHARACTERISTICS (continued)
(PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1F, RL = , resistive load referenced to ground, for MAX9722A gain = -1V/V (RIN = RF = 10k), for MAX9722B gain = -2V/V (internally set), TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER Total Harmonic Distortion Plus Noise (Note 4) Signal-to-Noise Ratio Noise Slew Rate Maximum Capacitive Load Charge-Pump Oscillator Frequency Crosstalk ESD Protection Thermal-Shutdown Threshold Thermal-Shutdown Hysteresis SYMBOL THD+N SNR Vn SR CL fOSC RL = 32, VIN = 200mVP-P, f = 10kHz, AV = 1 Human Body Model (OUTR and OUTL) No sustained oscillation 505 CONDITIONS RL = 16, POUT = 55mW, f = 1kHz RL = 32, POUT = 125mW, f = 1kHz RL = 32, POUT = 20mW, f = 22Hz to 22kHz 22Hz to 22kHz bandwidth, input AC grounded MIN TYP 0.03 0.009 100 6 0.5 200 600 78 8 145 5 800 MAX UNITS % dB VRMS V/s pF kHz dB kV C C
MAX9722A/MAX9722B
Note 1: Note 2: Note 3: Note 4:
All specifications are 100% tested at TA = +25C; temperature limits are guaranteed by design. Gain for the MAX9722A is adjustable. The amplifier inputs are AC-coupled to ground through CIN_. Measurement bandwidth is 22Hz to 22kHz.
Typical Operating Characteristics
(MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1F, RL = , gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
MAX9722 toc01
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
MAX9722 toc02
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
VDD = 5V AV = -1V/V RL = 16 POUT = 5mW THD+N (%) 0.1 POUT = 60mW
MAX9722 toc03
10 VDD = 3V AV = -1V/V RL = 16
10 VDD = 3V AV = -1V/V RL = 32 POUT = 5mW THD+N (%) 0.1 POUT = 20mW
10
1 POUT = 15mW
POUT = 5mW
1
1
THD+N (%)
0.1
0.01 POUT = 30mW
0.01
0.01 POUT = 40mW
0.001
0.001
POUT = 40mW
0.001
0.0001 10 100 1k FREQUENCY (Hz) 10k 100k
0.0001 10 100 1k FREQUENCY (Hz) 10k 100k
0.0001 10 100 1k FREQUENCY (Hz) 10k 100k
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3
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
Typical Operating Characteristics (continued)
(MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1F, RL = , gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
MAX9722 toc04
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
MAX9722 toc05
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
VDD = 5V AV = -2V/V RL = 32
MAX9722 toc06
10 VDD = 5V AV = -2V/V RL = 16
10 VDD = 5V AV = -1V/V RL = 32 POUT = 5mW
10
1 POUT = 20mW
POUT = 5mW
1
1
POUT = 5mW
THD+N (%)
THD+N (%)
0.1
0.1
THD+N (%)
POUT = 20mW
0.1
POUT = 20mW
0.01 POUT = 40mW 0.001
0.01 POUT = 80mW
0.01 POUT = 80mW 0.001
0.001
0.0001 10 100 1k FREQUENCY (Hz) 10k 100k
0.0001 10 100 1k FREQUENCY (Hz) 10k 100k
0.0001 10 100 1k FREQUENCY (Hz) 10k 100k
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER
MAX9722 toc07
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER
MAX9722 toc08
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER
MAX9722 toc09
100 10 1 THD+N (%)
100 10 1 THD+N (%)
100 10 1 THD+N (%) f = 1kHz 0.1 0.01 f = 10kHz
f = 1kHz 0.1 0.01 0.001 f = 20Hz
f = 10kHz
f = 10kHz f = 1kHz
0.1 0.01
0.0001 0 10 20 30 40 50 OUTPUT POWER (mW)
VDD = 3V AV = -1V/V RL = 16 60 70
0.001 0.0001 0 10 20
f = 20Hz
VDD = 3V AV = -1V/V RL = 32 50 60 70 80
0.001 0.0001 0 10
f = 20Hz
VDD = 5V AV = -1V/V RL = 16 40 50 60 70
30
40
20
30
OUTPUT POWER (mW)
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER
VDD = 5V AV = -2V/V RL = 16
MAX9722 toc10
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER
MAX9722 toc11
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER
VDD = 5V AV = -2V/V RL = 32 f = 10kHz f = 1kHz
MAX9722 toc12
100 10 1 THD+N (%) 0.1 0.01 0.001 0.0001 0
100 10 1 THD+N (%)
f = 10kHz
VDD = 5V AV = -1V/V RL = 32 f = 10kHz f = 1kHz
100 10 1 THD+N (%) 0.1 0.01 0.001 0.0001
f = 1kHz
0.1 0.01
f = 20Hz
0.001 0.0001
f = 20Hz 0 20 40 60 80 100 120 140
f = 20Hz
10
20
30
40
50
60
70
0
20
40
60
80
100
120
140
OUTPUT POWER (mW)
OUTPUT POWER (mW)
OUTPUT POWER (mW)
4
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5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
Typical Operating Characteristics (continued)
(MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1F, RL = , gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER
MAX9722 toc13
MAX9722A/MAX9722B
TOTAL HARMONIC DISTORTION PLUS NOISE vs. COMMON-MODE VOLTAGE
VDD = 5V AV = -1V/V f = 1kHz DIFFERENTIAL RL = 16
MAX9722 toc14
OUTPUT POWER vs. SUPPLY VOLTAGE
90 80 OUTPUT POWER (mW) 70 60 50 40 30 20 10 f = 1kHz RL = 16 2.4 2.6 2.8 3.0 3.2 3.4 3.6 THD+N = 1% THD+N = 10%
MAX9722 toc15
100 10 1 THD+N (%) 0.1 0.01 0.001 0.0001 0
VDD = 5V AV = -1V/V RL = 16 DIFFERENTIAL
100 10 1 THD+N (%) 0.1 0.01
100
f = 10kHz
f = 1kHz
RL = 32 f = 20Hz 0.001 0.0001 10 20 30 40 50 60 70 -0.5 -0.3 -0.1 0.1 0.3 0.5 OUTPUT POWER (mW) COMMON-MODE VOLTAGE (V)
0 SUPPLY VOLTAGE (V)
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9722 toc16
OUTPUT POWER vs. LOAD RESISTANCE
MAX9722 toc17
OUTPUT POWER vs. LOAD RESISTANCE
180 160 OUTPUT POWER (mW) 140 120 100 80 60 40 20 0 THD+N = 1% THD+N = 10% VDD = 5V f = 1kHz AV = -1V/V
MAX9722 toc18
200 180 160 OUTPUT POWER (mW) 140 120 100 80 60 40 20 0 2.4 2.9 3.4 3.9 4.4 f = 1kHz RL = 32 THD+N = 1% THD+N = 10%
100 90 80 OUTPUT POWER (mW) 70 60 50 40 30 20 10 0 THD+N = 1% THD+N = 10% VDD = 3V f = 1kHz AV = -1V/V
200
4.9
10
100 LOAD RESISTANCE ()
1000
10
100 LOAD RESISTANCE ()
1000
SUPPLY VOLTAGE (V)
POWER DISSIPATION vs. OUTPUT POWER
MAX9722 toc19
POWER DISSIPATION vs. OUTPUT POWER
MAX9722 toc20
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
-10 -20 -30 VDD = 3V AV = -1V/V RL = 32
MAX9722 toc21
300 250 POWER DISSIPATION (mW) 200 150 100 50 0 0 10 20 30 40 50 60 VDD = 3V f = 1kHz POUT = PL + PR RL = 16
600 500 POWER DISSIPATION (mW) 400
VDD = 5V f = 1kHz POUT = PL + PR
0
RL = 16 300 200 100 0 RL = 32
PSRR (dB)
-40 -50 -60 -70 -80 -90 -100 RIGHT LEFT
RL = 32
70
0
20
40
60
80
100
10
100
1k FREQUENCY (Hz)
10k
100k
OUTPUT POWER (mW)
OUTPUT POWER (mW)
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5
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
Typical Operating Characteristics (continued)
(MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1F, RL = , gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.)
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
MAX9722 toc22
CROSSTALK vs. FREQUENCY
MAX9722 toc23
CROSSTALK vs. FREQUENCY
-10 -20 CROSSTALK (dB) -30 -40 -50 -60 -70 -80 RIGHT TO LEFT VDD = 5V AV = -1V/V VIN = 200mVP-P RL = 32
MAX9722 toc24
0 -10 -20 -30 PSRR (dB) -40 -50 -60 -70 -80 -90 -100 10
0 -10 -20 CROSSTALK (dB) -30 -40 -50 -60 -70 -80
VDD = 5V AV = -1V/V RL = 32
VDD = 3V AV = -1V/V VIN = 200mVP-P RL = 32
0
RIGHT TO LEFT
RIGHT
LEFT 100 1k FREQUENCY (Hz) 10k 100k
-90 -100 10 100
LEFT TO RIGHT 1k FREQUENCY (Hz) 10k 100k
-90 -100 10 100
LEFT TO RIGHT 1k FREQUENCY (Hz) 10k 100k
GAIN FLATNESS vs. FREQUENCY
MAX9722 toc25
CHARGE-PUMP OUTPUT RESISTANCE vs. SUPPLY VOLTAGE
9 OUTPUT RESISTANCE () 8 7 6 5 4 3 2 VIN = GND IPVSS = 10mA C1 = C2 = 2.2F NO LOAD
MAX9722 toc26
OUTPUT POWER vs. LOAD RESISTANCE
C1 = C2 = 2.2F 50 OUTPUT POWER (mW) 40 30 20 10 0 C1 = C2 = 0.68F C1 = C2 = 1F C1 = C2 = 0.47F
MAX9722 toc27
4 3 2 GAIN (dB) 1 0 -1 -2 -3 -4 10
VDD = 5V AV = -1V/V RL = 32
10
60
1 0 100 1k FREQUENCY (Hz) 10k 100k 2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2 5.6 SUPPLY VOLTAGE (V) 10 20 30
VDD = 3V f = 1kHz AV = -1V/V THD+N = 1% 40 50
LOAD RESISTANCE ()
OUTPUT SPECTRUM vs. FREQUENCY
MAX9722 toc28
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX9722 toc29
SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE
18 16 SUPPLY CURRENT (nA) 14 12 10 8 6 4 2 0
MAX9722 toc30
10 0 -10 -20 OUTPUT (dBc) -30 -40 -50 -60 -70 -80 -90 -100 0 5 10
SUPPLY CURRENT (mA)
VDD = 5V RL = 32 VOUT = 1mVRMS f = 1kHz AV = -1V/V
8 7 6 5 4 3 2 1 0
20
15
20
0
1
2
3
4
5
0
1
2
3
4
5
FREQUENCY (kHz)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
6
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5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
Typical Operating Characteristics (continued)
(MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1F, RL = , gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.)
MAX9722A/MAX9722B
EXIT SHUTDOWN TRANSIENT
MAX9722 toc31
SHUTDOWN TRANSIENT
MAX9722 toc32
POWER-UP/DOWN TRANSIENT
MAX9722 toc33
SHDN 2V/div
SHDN 2V/div
VDD 2V/div
OUT 500mV/div
OUT 500mV/div
OUT 5mV/div
200s/div
400s/div
20ms/div
Pin Description
PIN THIN QFN 1 2 3 4 5 6 7 8 9, 13 10 11 12 14 15 16 -- TSSOP 3 4 5 6 7 8 9 10 11, 15 12 13 14 16 1 2 -- NAME FUNCTION Charge-Pump Power Supply. Powers charge-pump inverter, charge-pump logic, and oscillator. Connect to positive supply (2.4V to 5.5V). Bypass with a 1F capacitor to PGND as close to the pin as possible. Flying Capacitor Positive Terminal Power Ground. Connect to ground. Flying Capacitor Negative Terminal Charge-Pump Output. Connect to SVSS. Signal Ground. Connect to ground. Noninverting Right-Channel Audio Input Inverting Right-Channel Audio Input Amplifier Positive Power Supply. Connect to positive supply (2.4V to 5.5V). Bypass with a 1F capacitor to SGND as close to the pin as possible. Right-Channel Output Amplifier Negative Power Supply. Connect to PVSS. Left-Channel Output Inverting Left-Channel Audio Input Noninverting Left-Channel Audio Input Active-Low Shutdown Input Exposed Paddle. Leave this connection unconnected or solder to a piece of electrically isolated copper. Do not connect to any voltage potential.
PVDD C1P PGND C1N PVSS SGND INR+ INRSVDD OUTR SVSS OUTL INLINL+ SHDN EP
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7
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
Detailed Description
The MAX9722A/MAX9722B stereo headphone amplifiers feature Maxim's patented DirectDrive architecture, eliminating the large output-coupling capacitors required by conventional single-supply headphone amplifiers. The devices consist of two class AB headphone amplifiers, undervoltage lockout (UVLO)/shutdown control, charge pump, and comprehensive click-and-pop suppression circuitry (see Typical Application Circuit). The charge pump inverts the positive supply (PVDD), creating a negative supply (PVSS). The headphone amplifiers operate from these bipolar supplies with their outputs biased about GND (Figure 1). The benefit of this GND bias is that the amplifier outputs do not have a DC component, typically V DD /2. The large DC-blocking capacitors required with conventional headphone amplifiers are unnecessary, thus conserving board space, reducing system cost, and improving frequency response. The device features an undervoltage lockout that prevents operation from an insufficient power supply and clickand-pop suppression that eliminates audible transients on startup and shutdown. Additionally, the MAX9722A/ MAX9722B feature thermal-overload and short-circuit protection and can withstand 8kV ESD strikes at the output pins.
VDD VOUT
VDD/2 GND
CONVENTIONAL DRIVER-BIASING SCHEME
+VDD OR 3V
VOUT
GND
Differential Input
The MAX9722 can be configured as a differential input amplifier (Figure 2), making it compatible with many CODECs. A differential input offers improved noise immunity over a single-ended input. In devices such as cellular phones, high-frequency signals from the RF transmitter can couple into 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 cancelled. Configured differentially, the gain of the MAX9722 is set by: AV = RF1/RIN1 RIN1 must be equal to RIN2, and RF1 must be equal to RF2. The common-mode rejection ratio (CMRR) is limited by the external resistor matching. For example, the worstcase variation of 1% tolerant resistors results in 40dB CMRR, while 0.1% resistors result in 60dB CMRR. For best matching, use resistor arrays. The RIN1 and RF1 of the MAX9722B are internal, set R IN2 = 15k and R F2 = 30k. However, for best results, use the MAX9722A.
DirectDrive BIASING SCHEME
-VDD OR -3V
Figure 1. Conventional Driver Output Waveform vs. MAX9722A/ MAX9722B Output Waveform
RF1*
RIN1* INRIN2 IN+ RF2 OUT
RIN1 = RIN2, RF1 = RF2 *RIN1 AND RF1 ARE INTERNAL FOR MAX9722B.
Figure 2. Differential Input Configuration
8
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5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
DirectDrive
Conventional single-supply headphone amplifiers have their outputs biased about a nominal DC voltage (typically half the supply) for maximum dynamic range. Large coupling capacitors are needed to block this DC bias from the headphone. Without these capacitors, a significant amount of DC current flows to the headphone, resulting in unnecessary power dissipation and possible damage to both the headphone and the headphone amplifier. Maxim's patented DirectDrive architecture uses a charge pump to create an internal negative supply voltage, allowing the MAX9722A/MAX9722B outputs to be biased about GND. With no DC component, there is no need for the large DC-blocking capacitors. Instead of two large (220F, typ) tantalum capacitors, the MAX9722A/MAX9722B charge pump requires two small ceramic capacitors, conserving board space, reducing cost, and improving the frequency response of the headphone amplifier. See the Output Power vs. Charge-Pump Capacitance and Load Resistance graph in the Typical Operating Characteristics for details of the possible capacitor sizes. There is a low DC voltage on the amplifier outputs due to amplifier offset. However, the offset of the MAX9722A is typically 0.5mV, which, when combined with a 32 load, results in less than 15.6A of DC current flow to the headphones. Previous attempts to eliminate the output-coupling capacitors involved biasing the headphone return (sleeve) to the DC-bias voltage of the headphone amplifiers. This method raises some issues: * The sleeve is typically grounded to the chassis. Using this biasing approach, the sleeve must be isolated from system ground, complicating product design. * During an ESD strike, the amplifier's ESD structures are the only path to system ground. Thus, the amplifier must be able to withstand the full ESD strike. * When using the headphone jack as a line out to other equipment, the bias voltage on the sleeve may conflict with the ground potential from other equipment, resulting in possible damage to the amplifiers. * When using a combination microphone and speaker headset, the microphone typically requires a GND reference. The amplifier DC bias on the sleeve conflicts with the microphone requirements (Figure 3). Low-Frequency Response In addition to the cost and size disadvantages of the DCblocking capacitors required by conventional headMICROPHONE BIAS MICROPHONE AMPLIFIER MICROPHONE AMPLIFIER OUTPUT
MAX9722A/MAX9722B
AUDIO INPUT
AUDIO INPUT
MAX9722
HEADPHONE DRIVER
Figure 3. Earbud Speaker/Microphone Combination Headset Configuration
phone amplifiers, these capacitors limit the amplifier's low-frequency response and can distort the audio signal: 1) The impedance of the headphone load and the DCblocking capacitor form a highpass filter with the -3dB point set by: f-3dB = 1 2RLCOUT
where R L is the impedance of the headphone and COUT is the value of the DC-blocking capacitor. The highpass filter is required by conventional singleended, single power-supply headphone amplifiers to block the midrail DC-bias component of the audio signal from the headphones. The drawback to the filter is that it can attenuate low-frequency signals. Larger values of COUT reduce this effect but result in physically larger, more expensive capacitors. Figure 4 shows the relationship between the size of COUT and the resulting low-frequency attenuation. Note that the -3dB point for a 16 headphone with a 100F blocking capacitor is 100Hz, well within the normal audio band, resulting in low-frequency attenuation of the reproduced signal.
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9
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
LOW-FREQUENCY ROLLOFF (RL = 16)
0 -3 -6 ATTENUATION (dB) -9 -12 -15 -18 -21 -24 -27 -30 10 100 1k FREQUENCY (Hz) 10k 100k 0.0001 10 100 1k FREQUENCY (Hz) 10k 100k 33F 0.001 ALUM/ELEC DirectDrive 330F 220F 100F THD+N (%) 0.1 TANTALUM 0.01 1 10
ADDITIONAL THD+N DUE TO DC-BLOCKING CAPACITORS
Figure 4. Low-Frequency Attenuation for Common DC-Blocking Capacitor Values
Figure 5. Distortion Contributed by DC-Blocking Capacitors
2) The voltage coefficient of the DC-blocking capacitor contributes distortion to the reproduced audio signal as the capacitance value varies and the function of the voltage across the capacitor changes. The reactance of the capacitor dominates at frequencies below the -3dB point and the voltage coefficient appears as frequency-dependent distortion. Figure 5 shows the THD+N introduced by two different capacitor dielectric types. Note that below 100Hz, THD+N increases rapidly. The combination of low-frequency attenuation and frequency-dependent distortion compromises audio reproduction in portable audio equipment that emphasizes low-frequency effects such as in multimedia laptops, MP3, CD, and DVD players. By eliminating the DC-blocking capacitors through DirectDrive technology, these capacitor-related deficiencies are eliminated. Charge Pump The MAX9722A/MAX9722B feature a low-noise charge pump. The 600kHz switching frequency is well beyond the audio range and, thus, does not interfere with the audio signals. Also, the 600kHz switching frequency does not interfere with the 450kHz AM transceivers. The switch drivers feature a controlled switching speed that minimizes noise generated by turn-on and turn-off transients. By limiting the switching speed of the charge pump, the di/dt noise caused by the parasitic bond wire and trace inductance is minimized. Although not typically required, additional high-frequency noise attenuation can be achieved by increasing the value of C2 (see Typical Application Circuit).
10
Click-and-Pop Suppression
In conventional single-supply audio amplifiers, the output-coupling capacitor is a major contributor of audible clicks and pops. Upon startup, the amplifier charges the coupling capacitor to its bias voltage, typically half the supply. Likewise, on shutdown, the capacitor is discharged to GND. This results in a DC shift across the capacitor, which, in turn, appears as an audible transient at the speaker. Since the MAX9722A/MAX9722B do not require output-coupling capacitors, this problem does not arise. Additionally, the MAX9722A/MAX9722B feature extensive click-and-pop suppression that eliminates any audible transient sources internal to the device. The Power-Up/Down Waveform in the Typical Operating Characteristics shows that there is minimal DC shift and no spurious transients at the output upon startup or shutdown. In most applications, the output of the preamplifier driving the MAX9722A/MAX9722B has a DC bias of typically half the supply. At startup, the input-coupling capacitor is charged to the preamplifier's DC-bias voltage through the feedback resistor of the MAX9722A/MAX9722B, resulting in a DC shift across the capacitor and an audible click/pop. Delaying the rise of SHDN 4 to 5 time constants (80ms to 100ms) based on RIN and CIN, relative to the startup of the preamplifier, eliminates this click/pop caused by the input filter.
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5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
Shutdown
The MAX9722A/MAX9722B feature shutdown control allowing audio signals to be shut down or muted. Driving SHDN low disables the amplifiers and the charge pump, sets the amplifier output impedance to 10k, and reduces the supply current. In shutdown mode, the supply current is reduced to 0.1A. The charge pump is enabled once SHDN is driven high.
OUTPUT POWER vs. SUPPLY VOLTAGE
140 OUTPUT POWER (mW) 120 100 80 60 40 20 0 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 SUPPLY VOLTAGE (V) INPUTS IN PHASE fIN = 1kHz RL = 32 THD+N = 10% INPUTS 180 OUT OF PHASE
MAX9722 fig06
MAX9722A/MAX9722B
160
Applications Information
Power Dissipation
Under normal operating conditions, linear power amplifiers can dissipate a significant amount of power. The maximum power dissipation for each package is given in the Absolute Maximum Ratings section under Continuous Power Dissipation or can be calculated by the following equation: PDISSPKG(MAX) = TJ(MAX) - TA JA
Figure 6. Distortion Contributed by DC-Blocking Capacitors
where TJ(MAX) is +145C, TA is the ambient temperature, and JA is the reciprocal of the derating factor in C/W as specified in the Absolute Maximum Ratings section. For example, JA of the thin QFN package is +63.8C/W, and 99.3C/W for the TSSOP package. The MAX9722A/MAX9722B have two power dissipation sources: the charge pump and two amplifiers. If power dissipation for a given application exceeds the maximum allowed for a particular package, either reduce SVDD, increase load impedance, decrease the ambient temperature, or add heatsinking to the device. Large output, supply, and ground traces improve the maximum power dissipation in the package. Thermal-overload protection limits total power dissipation in the MAX9722A/MAX9722B. When the junction temperature exceeds +145C, the thermal-protection circuitry disables the amplifier output stage. The amplifiers are enabled once the junction temperature cools by 5C. This results in a pulsing output under continuous thermal-overload conditions. Output Power The device has been specified for the worst-case scenario--when both inputs are in-phase. Under this condition, the amplifiers simultaneously draw current from the charge pump, leading to a slight loss in SVSS headroom. In typical stereo audio applications, the left and right signals have differences in both magnitude and phase, subsequently leading to an increase in the max-
imum attainable output power. Figure 6 shows the two extreme cases for in- and out-of-phase. In reality, the available power lies between these extremes.
Powering Other Circuits from a Negative Supply
An additional benefit of the MAX9722A/MAX9722B is the internally generated, negative supply voltage (PVSS). This voltage provides the ground-referenced output level. PVSS can, however, be used to power other devices within a design limit current drawn from PVSS to 5mA; exceeding this affects the headphone amplifier operation. A typical application is a negative supply to adjust the contrast of LCD modules. PVSS is roughly proportional to PVDD and is not a regulated voltage. The charge-pump output impedance must be taken into account when powering other devices from PVSS. The charge-pump output impedance plot appears in the Typical Operating Characteristics. For best results, use 1F charge-pump capacitors.
UVLO
The MAX9722A/MAX9722B feature an UVLO function that prevents the device from operating if the supply voltage is less than 2.2V (typ). This feature ensures proper operation during brownout conditions and prevents deep battery discharge. Once the supply voltage reaches the UVLO threshold, the MAX9722A/ MAX9722B charge pump is turned on and the amplifiers are powered.
______________________________________________________________________________________
11
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
Component Selection
Input Filtering The input capacitor (CIN), in conjunction with the input resistor (RIN), forms a highpass filter that removes the DC bias from an incoming signal (see the Typical Application Circuit). The AC-coupling capacitor allows the device to bias the signal to an optimum DC level. Assuming zero source impedance, the -3dB point of the highpass filter is given by: f-3dB = 1 2RINCIN
RF
LEFT AUDIO INPUT
RIN
INL-
MAX9722A
OUTL
INL+ INR+ OUTR RIGHT AUDIO INPUT RIN INRRF
Choose CIN so f-3dB is well below the lowest frequency of interest. For the MAX9722B, use the value of RIN as given in the DC Electrical Characteristics table. Setting f-3dB too high affects the device's low-frequency response. Use capacitors whose dielectrics have low-voltage coefficients, such as tantalum or aluminum electrolytic. Capacitors with high-voltage coefficients, such as ceramics, can result in increased distortion at low frequencies. Charge-Pump Capacitor Selection Use capacitors with an ESR less than 100m for optimum performance. Low-ESR ceramic capacitors minimize the output resistance of the charge pump. For best performance over the extended temperature range, select capacitors with an X7R dielectric. Table 1 lists suggested manufacturers. Flying Capacitor (C1) The value of the flying capacitor (C1) affects the charge pump's load regulation and output resistance. 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 1F, the on-resistance of the switches and the ESR of C1 and C2 dominate. Hold Capacitor (C2) The hold capacitor value and ESR directly affect the ripple at PVSS. Increasing the value of C2 reduces output ripple. Likewise, decreasing the ESR of C2 reduces both ripple and output resistance. Lower capacitance values
Figure 7. Gain Setting for the MAX9722A
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. Power-Supply Bypass Capacitor The power-supply bypass capacitor (C3) lowers the output impedance of the power supply and reduces the impact of the MAX9722A/MAX9722Bs' charge-pump switching transients. Bypass PVDD with C3, the same value as C1, and place it physically close to the PVDD and PGND pins.
Amplifier Gain
The gain of the MAX9722B is internally set at -2V/V. All gain-setting resistors are integrated into the device, reducing external component count. The internally set gain, in combination with DirectDrive, results in a headphone amplifier that requires only five tiny 1F capacitors to complete the amplifier circuit: two for the charge pump, two for audio input coupling, and one for powersupply bypassing (see the Typical Application Circuit). The gain of the MAX9722A amplifier is set externally as shown in Figure 7, the gain is: AV = -RF/RIN Choose feedback resistor values of 10k. Values other than 10k increase output offset voltage due to the input bias current, which, in turn, increases the amount of DC current flow to the load.
Table 1. Suggested Capacitor Manufacturers
SUPPLIER Murata Taiyo Yuden TDK PHONE 770-436-1300 800-348-2496 847-803-6100 FAX 770-436-3030 847-925-0899 847-390-4405 WEBSITE www.murata.com www.t-yuden.com www.component.tdk.com
12
______________________________________________________________________________________
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
Common-Mode Sense
When the headphone jack is used as a line out to interface between other equipment (notebooks, desktops, and stereo receivers), potential differences between the equipment grounds can create ground loops and excessive ground-current flow. The MAX9722A's INR+ and INL+ inputs are connected together to form a common-mode input that senses and corrects for the difference between the headphone return and device ground (see Figure 8). Connect INR+ and INL+ through a resistive voltage-divider between the headphone jack return and SGND of the device. For optimum commonmode rejection, use the same value resistors for R1 and RIN, and R2 and RF. For the MAX9722B, RIN = 15k and R F = 30k. Improve DC CMRR by adding a capacitor between SGND and R 2 (see the Typical Application Circuit). If ground sensing is not required, connect INR+ and INL+ directly to SGND.
MAX9722A/MAX9722B
MAX9722A
LEFT AUDIO INPUT
SHDN
R1
RIGHT AUDIO INPUT
R2
Common-Mode Noise Rejection
Figure 8. Common-Mode Sense Input Eliminates Ground-Loop Noise
Figure 9 shows a theoretical connection between two devices, for example, a notebook computer (transmitter, on the left) and an amplifier (receiver, on the right),
VIN = VAUDIO GND NOISE COMPONENT IN OUTPUT = VNOISE/2 0.1 VNOISE 0.1 VREF_IN = VNOISE/2
EXAMPLE CONNECTION: VAUDIO
IMPROVEMENT FROM ADDING MAX9722 WITH SERIES RESISTANCE
* 0.10 RESISTANCE FROM CABLE SCREEN. * 0.10 RESISTANCE DUE TO GND CABLING AT RECEIVER. * VNOISE REPRESENTS THE POTENTIAL DIFFERENCE BETWEEN THE TWO GNDS.
MAX9722A
VAUDIO
VIN = VAUDIO + (VNOISE x 0.98) GND NOISE COMPONENT IN OUTPUT = VNOISE /100
0.1 RESISTOR IS INSERTED BETWEEN THE JACK SLEEVE AND GND = 9.8 9.8 VNOISE 0.1
VREF_IN = (VNOISE x 0.99)
* 9.8 RESISTOR ADDS TO HP CROSSTALK, BUT DIFFERENTIAL SENSING AT THE JACK SLEEVE CORRECTS FOR THIS (ONE CHANNEL ONLY SHOWN). * CURRENT FLOW (IN SIGNAL CABLE SCREEN) DUE TO VNOISE IS GREATLY REDUCED. * NOISE COMPONENT IN THE RECEIVER OUTPUT IS REDUCED BY 34dB OVER THE PREVIOUS EXAMPLE WITH THE VALUES SHOWN.
Figure 9. Common-Mode Noise Rejection ______________________________________________________________________________________ 13
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
such as the headphone socket used as a line output to a home hi-fi system. In the upper diagram, any difference between the two GND references (represented by VNOISE) causes current to flow through the screen of cable between the two devices. This can cause noise pickup at the receiver due to the potential divider action of the audio screen cable impedance and the GND wiring of the amplifier. Introducing impedance between the jack socket and GND of the notebook helps (as shown in the lower diagram). This has the following effect: Current flow (from GND potential differences) in the cable screen is reduced, which is a safety issue. It allows the MAX9722A/MAX9722B differential sensing to reduce the GND noise seen by the receiver (amplifier). The other side effect is that the differential headphone jack sensing corrects the headphone crosstalk (from introducing the resistance on the jack GND return). Only one channel is depicted in Figure 9. Figure 9 has some example numbers for resistance, but the audio designer has control over only one series resistance applied to the headphone jack return. Note that this resistance can be bypassed for ESD purposes at frequencies much higher than audio if required. The upper limit for this added resistance is the amount of output swing the headphone amplifier tolerates when driving low-impedance loads. Any headphone return current appears as a voltage across this resistor.
10k
1F AUDIO INPUT
10k
INR OUTR
10k INL
10k OUTL
MAX9722A
Figure 10. MAX9722 BTL Configuration
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT VOLTAGE
VDD = 5V AV = -1V/V OUTPUTS DRIVING PIEZOELECTRIC SPEAKER
MAX9722 fig11
100 10 1 THD+N (%) 0.1000 0.0100 f = 20Hz 0.0010 f = 100Hz 0.0001 0 2 4 6 8 10 12 f = 1kHz
Piezoelectric Speaker Amplifier
Low-profile piezoelectric speakers can provide quality sound for portable electronics. However, piezoelectric speakers typically require large voltage swings (>8VP-P) across the speaker element to produce usable sound pressure levels. Power sources in portable devices are usually low voltage in nature. Operating from batteries, conventional amplifiers cannot provide sufficient voltage swing to drive a piezoelectric speaker. However, the MAX9722's DirectDrive architecture can be configured to drive a piezoelectric speaker with up to 12VP-P while operating from a single 5V supply. The stereo MAX9722 features an inverting charge pump that takes the positive 5V supply and creates a negative -5V supply. Each output of the MAX9722 can swing 6VP-P. This may be sufficient to drive a piezoelectric speaker. If a higher output voltage is desired, configuring the MAX9722A as a bridge-tied load (BTL) amplifier (Figure 10) doubles the maximum output swing as seen by the load to 12VP-P. In a BTL configuration, the right channel of the MAX9722 serves as the master amplifier, setting the gain of the device, driving one side of the speaker, and providing signal to the left
14
14
OUTPUT POWER (mW)
Figure 11. MAX9722 THD+N vs. Output Voltage
channel. The left channel is configured as a unity-gain follower, inverting the output of the right channel and driving the other leg of the speaker. Use precision resistors to set the gain of the left channel to ensure low distortion and good matching. The MAX9722 was tested with a Panasonic WM-R57A piezoelectric speaker, and the resulting THD+N curves are shown (Figures 11 and 12). Note in both graphs, as frequency increases, the THD+N increases. This is due
______________________________________________________________________________________
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
VDD = 5V AV = -1V/V 1 VOUT(P-P) = 2V OUTPUTS DRIVING PIEZOELECTRIC SPEAKER
MAX9722 fig12
10
THD+N (%)
0.1
A
500mV/div
0.01
0.001 4s/div 0.0001 10 100 1k FREQUENCY (Hz) 10k 100k
Figure 12. MAX9722 THD+N vs. Frequency
B 500mV/div
to the capacitive nature of the piezoelectric speaker, as frequency increases, the speaker impedance decreases, resulting in a larger current draw from the amplifier. Furthermore, the capacitive nature of the speaker can cause the MAX9722 to become unstable. In these tests, the MAX9722 exhibited instabilities when driving the WM-R57A. A simple inductor/resistor network in series with the speaker isolates the speaker's capacitance from the amplifier, and ensures the device output sees a resistive load of about 10 at high frequency maintaining stability. Although the MAX9722 was not stable with the WM-R57A, a different speaker with different characteristics may result in stable operation, and elimination of the isolation components.
2s/div
Figure 13. MAX9722 Capacitive-Load Stability Waveform: (a) Falling Edge, (b) Rising Edge
10k 1F 10k
Layout and Grounding
Proper layout and grounding are essential for optimum performance. Connect PGND and SGND together at a single point on the PC board. Connect all components associated with the charge pump (C2 and C3) to the PGND plane. Connect PVDD and SVDD together at the device. Connect PVSS and SVSS together at the device. Bypassing of both supplies is accomplished by chargepump capacitors C2 and C3 (see the Typical Application Circuit). Place capacitors C2 and C3 as close to the device as possible. Route PGND and all traces that carry switching transients away from SGND and the traces and components in the audio signal path. Refer to the MAX9722 evaluation kit for layout guidelines.
AUDIO INPUT
INR OUTR
10
10k INL
100H
10k OUTL
MAX9722A
Figure 14. Isolation Network Improves Stability ______________________________________________________________________________________ 15
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
System Diagram
VDD 0.1F 15k 0.1F 15k INR VDD PVDD 0.1F AUX_IN OUT 0.1F 15k OUTR+ OUTR-
1F 1F
BIAS
MAX9710
SHDN OUTLINL CODEC 15k VDD OUTL+ VDD 10k INQ Q VDD 10k 100k 100k IN+ 0.1F SHDN 1F INLVDD 1F INRPVDD SVDD C1P CIN OUTR PVSS SVSS 1F 1F INL+ INR-
MAX4060
BIAS 2.2k 0.1F IN+ IN0.1F
MAX961
MAX9722B OUTL
1F
The thin QFN package features an exposed paddle that improves thermal efficiency of the package. The MAX9722A/MAX9722B do not require additional
heatsinking. Ensure the exposed paddle is isolated from GND or SVDD. Do not connect the exposed paddle to GND or SVDD.
16
______________________________________________________________________________________
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
Typical Application Circuit
2.4V TO 5.5V LEFT CHANNEL AUDIO IN 1 (3) PVDD 9, 13 (11, 15) SVDD 16 (2) SHDN CIN 1F
MAX9722A/MAX9722B
C3 1F
14 (16) INLRF* 30k SVDD 12 OUTL (14)
RIN* 15k
2 (4) C1P
UVLO/ SHUTDOWN CONTROL SVSS CHARGE PUMP
HEADPHONE JACK
C1 1F 4 (6) C1N
CLICK-AND-POP SUPPRESSION SVDD SGND 10 (12)
MAX9722A MAX9722B
RIN 15k SVSS RF 30k
OUTR
PVSS 5 (7) C2 1F
11 (13)
SVSS PGND 3 (5)
SGND 6 (8)
INR+ 7 (9) CIN 1F
INR8 (10)
RIGHT CHANNEL AUDIO IN *FOR MAX9722A, RIN AND RF ARE EXTERNAL TO THE DEVICE. ( ) FOR TSSOP PACKAGE.
______________________________________________________________________________________
17
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
Pin Configurations
SHDN SVDD
INL+ 15
TOP VIEW
INL+ 1 SHDN 2 PVDD 3 C1P 4 PGND 5 C1N 6 PVSS 7 SGND 8 16 INL15 SVDD 14 OUTL
16
14
INL-
PVDD C1P PGND C1N
1 2 3 4 5 6 7 8
13 12 11
OUTL SVSS OUTR SVDD
MAX9722A MAX9722B
13 SVSS 12 OUTR 11 SVDD 10 INR9 INR+
MAX9722A MAX9722B
10 9
PVSS
TSSOP
THIN QFN
Chip Information
TRANSISTOR COUNT: 1100 PROCESS: BiCMOS
18
______________________________________________________________________________________
SGND
INR+
INR-
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown
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.)
TSSOP4.40mm.EPS
MAX9722A/MAX9722B
______________________________________________________________________________________
19
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B
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.)
D2 b
0.10 M C A B
D D/2
D2/2
E/2
E2/2
C L
-A-
E
(NE - 1) X e
E2
L
-B-
e
k (ND - 1) X e
C L
C L
0.10 C 0.08 C
C L
A A2 A1 L L
e
e
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE 12 & 16L, QFN THIN, 3x3x0.8 mm
DOCUMENT CONTROL NO. REV.
APPROVAL
21-0136
1 2
C
EXPOSED PAD VARIATIONS
NOTES: 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. 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 0.20 mm AND 0.25 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 REVISION C.
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE 12 & 16L, QFN THIN, 3x3x0.8 mm
DOCUMENT CONTROL NO. REV.
APPROVAL
21-0136
2 2
C
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.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
12x16L QFN THIN.EPS

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