View MAX9702EUI_328387.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-3608; Rev 0; 6/05
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
General Description
The MAX9702 combines a highly efficient Class D speaker amplifier with a high-linearity Class AB headphone amplifier. This ensures maximum battery life in speaker mode and maximum performance in headphone mode. The MAX9702 delivers up to 1.8W per channel into an 8 load from a 5V power supply. Maxim's 2nd-generation, spread-spectrum modulation scheme renders the traditional Class D output filter unnecessary. The MAX9702 speaker amplifier offers two modulation schemes: a fixed-frequency (FFM) mode and a spreadspectrum (SSM) mode that reduces EMI-radiated emissions. The MAX9702 speaker amplifier features a fully differential architecture, full-bridged (BTL) output, and comprehensive click-and-pop suppression. The MAX9702 speaker amplifier features high 75dB PSRR, low 0.07% THD+N, and SNR in excess of 97dB. Shortcircuit and thermal-overload protection prevent the device from being damaged during a fault condition. The headphone amplifier uses Maxim's patented DirectDriveTM architecture that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, saving cost, board space, and component height. A high 80dB PSRR and low 0.02% THD+N ensures clean, low-distortion amplification of the audio signal. An I2C interface sets the speaker and headphone gain, mono, stereo, and mute functions. The MAX9702 is available in 28-pin thin QFN-EP (5mm x 5mm x 0.8mm) and 28-pin TSSOP packages. The MAX9702 is specified over the extended -40C to +85C temperature range.
Features
Patented Spread-Spectrum Modulation Reduces EMI Emissions Programmable Mono, Stereo, Mute, and Mix Functions 1.1W Stereo Output (8, VDD = 5V) 48mW Headphone Output (32, VDD = 3.3V) 95% Efficiency (RL = 8, PO = 1.1W) High 73dB PSRR (f = 217Hz) I2C Programmable Gain Up to +21dB Integrated Click-and-Pop Suppression Low-Power Shutdown Mode (0.1A) Short-Circuit and Thermal-Overload Protection 8kV (HBM) ESD-Protected Headphone Driver Outputs
MAX9702
Ordering Information
PART MAX9702EUI+ MAX9702ETI+ PIN-PACKAGE 28 TSSOP 28 TQFN-EP* I2C SLAVE ADDRESS 1001100 1001110 1001100 1001110 PKG CODE U28-1 U28-1 T2855-6 T2855-6
MAX9702BEUI+ 28 TSSOP MAX9702BETI+ 28 TQFN-EP*
Note: All devices specified for -40C to +85C operating temperature range. *EP = Exposed paddle. + Denotes lead-free package.
Simplified Block Diagram
RIGHT MODULATOR AND H-BRIDGE
Applications
Notebook PCs PDAs Handheld Gaming Consoles
INPUT MUX
Cellular Phones
INR INM INL
GAIN CONTROL LEFT MODULATOR AND H-BRIDGE
SHDN SDA SCL
*Purchase of I2C components from Maxim Integrated Products, Inc. or one of its sublicensed Associated Companies, conveys a license under the Philips I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips.
SYNC
I2C CONTROL OSCILLATOR
Pin Configurations appear at end of data sheet.
SYNC_OUT
MAX9702
________________________________________________________________ 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.
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
ABSOLUTE MAXIMUM RATINGS
VDD to GND ...........................................................................+6V PVDD to PGND .......................................................................+6V CPVDD to CPGND..................................................................+6V CPVSS to VSS ......................................................................0.3V CPVSS to CPGND .....................................................-6V to +0.3V VSS to CPGND..........................................................-6V to +0.3V C1N .......................................(CPVSS - 0.3V) to (CPGND + 0.3V) C1P.......................................(CPGND - 0.3V) to (CPVDD + 0.3V) HP_ to GND ............................(CPVSS - 0.3V) to (CPVDD + 0.3V) GND to PGND and CPGND................................................0.3V VDD to PVDD and CPVDD ....................................................0.3V SDA, SCL to GND.....................................................-0.3V to +6V All Other Pins to GND.................................-0.3V to (VDD + 0.3V) Continuous Current In/Out of PVDD, PGND, CPVDD, CPGND, OUT_ ..............................................600mA Continuous Current In/Out of HP_ ..................................120mA Continuous Input Current CPVSS....................................+260mA Continuous Input Current (all other pins) .........................20mA Duration of OUT_ Short Circuit to GND or PVDD .........Continuous Duration of Short Circuit Between OUT__ ..................Continuous Duration of HP_ Short Circuit to GND or PVDD ..................................................................Continuous Continuous Power Dissipation (TA = +70C) 28-Pin Thin QFN (derate 21.3mW/C above +70C)....1702mW 28-Pin TSSOP (derate 12.8mW/C above +70C) .....1026mW Junction Temperature ......................................................+150C Operating Temperature Range ...........................-40oC to +85C Storage Temperature Range .............................-65oC 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 (VDD = 3.3V)
(VDD = PVDD = CPVDD = SHDN = 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD (SSM), speaker gain = +12dB, headphone gain = +1dB. Speaker load RL connected between OUT+ and OUT-, unless otherwise noted, RL = . Headphone load RLH connected between HPR/HPL to GND. CBIAS = 1F to GND, 1F capacitor between C1P and C1N, CVSS = 1F. TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Notes 1, 2)
PARAMETER GENERAL Supply Voltage Range Quiescent Current Shutdown Current Input Resistance Debounced Delay VDD IDD ISHDN RIN tDEBOUNCE Inferred from PSRR test HPS = GND, speaker mode HPS = VDD, headphone mode Hard shutdown, SHDN = GND Soft shutdown (see I2C section) Stereo left and right Mono channel Delay from HPS transition to headphone/speaker turn-on Time from SHDN transition to full operation HPS = GND (SP mode) HPS = VDD (HP mode) 16.5 8.4 2.5 10 7 0.1 22 24 12 65 85 ms 85 0 1.125 TA = +25C TMIN to TMAX VDD = 2.5V to 5.5V PSRR 100mVP-P ripple, VIN = 0V, TA = +25C fRIPPLE = 217Hz fRIPPLE = 20kHz 54 75 75 55 dB 1.25 9 1.375 40 50 ms V 5.5 15 11 10 30 31.5 15.6 V mA mA A k ms SYMBOL CONDITIONS MIN TYP MAX UNITS
Turn-On Time Turn-Off Time Input Bias Voltage SPEAKER AMPLIFIERS (HPS = GND) Output Offset Voltage Power-Supply Rejection Ratio (Note 3)
tON tOFF VBIAS
VOS
mV
2
_______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (VDD = 3.3V) (continued)
(VDD = PVDD = CPVDD = SHDN = 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD (SSM), speaker gain = +12dB, headphone gain = +1dB. Speaker load RL connected between OUT+ and OUT-, unless otherwise noted, RL = . Headphone load RLH connected between HPR/HPL to GND. CBIAS = 1F to GND, 1F capacitor between C1P and C1N, CVSS = 1F. TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Notes 1, 2)
PARAMETER Output Power Total Harmonic Distortion Plus Noise SYMBOL POUT THD+N CONDITIONS THD+N = 1%, TA = +25C, f = 1kHz, VDD = 3.3V RL = 8 RL = 4 MIN TYP 470 700 0.07 0.13 86.5 87.5 91.5 91.5 1000 1250 1100 1340 1150 50 1000 100 Peak voltage, 32 samples/second, A-weighted (Note 3) Into shutdown Out of shutdown 56 48 94 0 +3 +6 +9 +12 +15 +18 +21 0.2 L to R, R to L, f = 10kHz, RL = 8, POUT = 300mW 65 % dB dB dB 2000 kHz pF 1200 1450 kHz dB MAX UNITS mW %
MAX9702
RL = 8 (POUT = 400mW), f = 1kHz RL = 4 (POUT = 600mW), f = 1kHz VOUT = 2VRMS, RL = 8 BW = 22Hz to 22kHz A-weighted FFM SSM FFM SSM
Signal-to-Noise Ratio
SNR
SYNC = GND Oscillator Frequency fS SYNC = float SYNC = VDD SYNC Frequency Lock Range SYNC_OUT Capacitance Drive Click-and-Pop Level fSYNC CSYNC_OUT KCP
Efficiency
POUT = 2 x 500mW, fIN = 1kHz, RL = 8, L = 68H B2 = 0 B2 = 0 B2 = 0 B2 = 0 B2 = 1 B2 = 1 B2 = 1 B2 = 1 B1 = 0 B1 = 0 B1 = 1 B1 = 1 B1 = 0 B1 = 0 B1 = 1 B1 = 1 B0 = 0 B0 = 1 B0 = 0 B0 = 1 B0 = 0 B0 = 1 B0 = 0 B0 = 1
%
Gain (see I2C Section)
AV
Channel-to-Channel Gain Tracking Crosstalk
_______________________________________________________________________________________
3
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
ELECTRICAL CHARACTERISTICS (VDD = 3.3V) (continued)
(VDD = PVDD = CPVDD = SHDN = 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD (SSM), speaker gain = +12dB, headphone gain = +1dB. Speaker load RL connected between OUT+ and OUT-, unless otherwise noted, RL = . Headphone load RLH connected between HPR/HPL to GND. CBIAS = 1F to GND, 1F capacitor between C1P and C1N, CVSS = 1F. TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Notes 1, 2)
PARAMETER SYMBOL TA = +25C TMIN to TMAX VDD = 2.5V to 5.5V PSRR 100mVP-P ripple, VIN = 0V, TA = +25C THD+N = 1%, VDD = 3.3V, TA = +25C fRIPPLE = 217Hz fRIPPLE = 20kHz RL = 32 RL = 16 66 75 73 53 48 47 0.03 0.015 95.5 97.9 fOSC/2 Peak voltage, 32 samples/second, A-weighted (Note 3) 1V output step B4 = 0 Gain (see I2C Section) AV B4 = 0 B4 = 1 B4 = 1 Channel-to-Channel Gain Tracking Capacitance Drive Crosstalk HP_ Resistance to GND Input Voltage High, SHDN, SYNC, HPS Input Voltage High, SCL Input Voltage Low, SHDN, SYNC, HPS CL No sustained oscillations L to R, R to L, f = 10kHz, RL = 16, POUT = 10mW In speaker mode B3 = 0 B3 = 1 B3 = 0 B3 = 1 Into shutdown Out of shutdown 65 85 0.3 -2 +1 +4 +7 0.2 300 70 1 % pF dB k dB dB V/s mW % dB kHz dB CONDITIONS MIN TYP 1.8 MAX 6 8 UNITS
HEADPHONE AMPLIFIERS (HPS = VDD) Output Offset Voltage Power-Supply Rejection Ratio (Note 4) Output Power Total Harmonic Distortion Plus Noise Signal-to-Noise Ratio Charge-Pump Frequency Click-and-Pop Level Slew Rate VOS mV
POUT THD+N SNR fCP KCP SR
RL = 16 (POUT = 40mW, f = 1kHz) RL = 32 (POUT = 32mW, f = 1kHz) VOUT = 1VRMS, RL = 32 BW = 22Hz to 22kHz A-weighted
DIGITAL INPUTS (SHDN, SYNC, SDA, SCL, HPS) VINH VINH VINL 2 0.7 x VDD 0.8 V V V
4
_______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (VDD = 3.3V) (continued)
(VDD = PVDD = CPVDD = SHDN = 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD (SSM), speaker gain = +12dB, headphone gain = +1dB. Speaker load RL connected between OUT+ and OUT-, unless otherwise noted, RL = . Headphone load RLH connected between HPR/HPL to GND. CBIAS = 1F to GND, 1F capacitor between C1P and C1N, CVSS = 1F. TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Notes 1, 2)
PARAMETER Input Voltage Low, SDA, SCL Input Hysteresis, SDA, SCL Input Capacitance SDA, SCL Input Leakage Current, SHDN, SCL Input Leakage Current, HPS SYNC Input Current HPS Pullup Resistance DIGITAL OUTPUTS (SYNC_OUT) Output Voltage High Output Voltage Low Output Fall Time, SDA VOH VOL tF IOH = 3mA IOL = 3mA 2.4 0.4 300 V V ns SYMBOL VINL VHYS CIN IIN IIN In play mode 10 25 600 0.05 x VDD 10 1 CONDITIONS MIN TYP MAX 0.3 x VDD UNITS V V pF A A A k
MAX9702
ELECTRICAL CHARACTERISTICS (VDD = 5V)
(VDD = PVDD = CPVDD = SHDN = 5V, GND = PGND = CPGND = 0V, SYNC = VDD (SSM), speaker gain = +12dB, headphone gain = +1dB. Speaker load RL connected between OUT+ and OUT-, unless otherwise noted, RL = . Headphone load RLH connected between HPR/HPL to GND. CBIAS = 1F to GND, 1F capacitor between C1P and C1N, CVSS = 1F. TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Notes 1, 2)
PARAMETER GENERAL Quiescent Current Shutdown Current IDD ISHDN HPS = GND, speaker mode HPS = VDD, headphone mode Hard shutdown, SHDN = GND Soft shutdown (see I2C section) 14 8 0.2 25 mA A SYMBOL CONDITIONS MIN TYP MAX UNITS
SPEAKER AMPLIFIERS (HPS = GND) Power-Supply Rejection Ratio (Note 3) PSRR 100mVP-P ripple, VIN = 0V, TA = +25C THD+N = 1%, TA = +25C, f = 1kHz fRIPPLE = 217Hz fRIPPLE = 20kHz RL = 8 VDD = 5V RL = 4 1800 73 dB 50 1100 mW
Output Power
POUT
_______________________________________________________________________________________
5
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
ELECTRICAL CHARACTERISTICS (VDD = 5V) (continued)
(VDD = PVDD = CPVDD = SHDN = 5V, GND = PGND = CPGND = 0V, SYNC = VDD (SSM), speaker gain = +12dB, headphone gain = +1dB. Speaker load RL connected between OUT+ and OUT-, unless otherwise noted, RL = . Headphone load RLH connected between HPR/HPL to GND. CBIAS = 1F to GND, 1F capacitor between C1P and C1N, CVSS = 1F. TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25oC.) (Notes 1, 2)
PARAMETER Total Harmonic Distortion Plus Noise SYMBOL THD+N CONDITIONS RL = 8 (POUT = 900mW), f = 1kHz RL = 4 (POUT = 1500mW), f = 1kHz VOUT = 2VRMS, RL = 8 BW = 22Hz to 22kHz A-weighted FFM SSM FFM SSM MIN TYP 0.08 0.18 88 87 91 89 61.5 dB Out of shutdown 44 95 0.2 L to R, R to L, f = 10kHz, RL = 8, POUT = 300mW 100mVP-P ripple, VIN = 0V, TA = +25C fRIPPLE = 217Hz fRIPPLE = 20kHz 65 % % dB dB MAX UNITS %
Signal-to-Noise Ratio
SNR
Click-and-Pop Level Efficiency Channel-to-Channel Gain Tracking Crosstalk
KCP
Peak voltage, 32 samples/second, A-weighted (Note 4)
Into shutdown
POUT = 1W, fIN = 1kHz, RL = 8, L = 68H
HEADPHONE AMPLIFIERS (HPS = VDD) Power-Supply Rejection Ratio (Note 4) Output Power Total Harmonic Distortion Plus Noise Signal-to-Noise Ratio PSRR POUT THD+N SNR 78 53 45 0.03 94.7 97.4 67 dB Out of shutdown 83 0.2 L to R, R to L, f = 10kHz, RL = 32, POUT = 10mW 70 % dB dB mW % dB
THD+N = 1%, TA = +25C, RL = 32 RL = 32 (POUT = 32mW, f = 1kHz) VOUT = 1VRMS, RL = 32 Peak voltage, 32 samples/second, A-weighted (Notes 3, 4) BW = 22Hz to 22kHz A-weighted Into shutdown
Click-and-Pop Level
KCP
Channel-to-Channel Gain Tracking Crosstalk
6
_______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
I2C TIMING CHARACTERISTICS
(VDD = PVDD = CPVDD = SHDN = 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD (SSM), speaker gain = +12dB, headphone gain = +1dB. Speaker load RL connected between OUT+ and OUT-, unless otherwise noted. RL = . Headphone load RLH connected between HPR/HPL and GND. CBIAS = 1F to GND, 1F capacitor between C1P and C1N, CVSS = 1F. TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25oC.) (Figure 9)
PARAMETER Serial Clock Bus Free Time Between a STOP and a START Condition Hold Time (Repeated) START Condition Repeated START Condition Setup Time STOP Condition Setup Time Data Hold Time Data Setup Time SCL Clock Low Period SCL Clock High Period Rise Time of SDA and SCL, Receiving Fall Time of SDA and SCL, Receiving Fall Time of SDA, Transmitting Pulse Width of Spike Suppressed Capacitive Load for Each Bus Line SYMBOL fSCL tBUF tHD, STA tSU, STA tSU, STO tHD,DAT tSU,DAT tLOW tHIGH tR tF tF tSP Cb (Note 5) (Note 5) (Note 5) 1.3 0.6 0.6 0.6 0 100 1.3 0.6 20 + 0.1Cb 20 + 0.1Cb 20 + 0.1Cb 0 300 300 250 50 400 0.9 CONDITIONS MIN TYP MAX 400 UNITS kHz s s s s s ns s s ns ns ns ns pF
MAX9702
Note 1: All devices are 100% production tested at +25C. All temperature limits are guaranteed by design. Note 2: Speaker mode testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For RL = 4, L = 34H, RL = 8, L = 68H. Note 3: Amplifier inputs (STEREO/MONO) connected to GND through CIN. Note 4: Speaker mode testing performed with an 8 resistive load in series with a 68H inductive load connected across BTL output. Headphone mode testing performed with 32 resistive load connected to GND. Mode transitions are controlled by SHDN. KCP level is calculated as: 20 x log[(peak voltage under normal operation at rated power level)/(peak voltage during mode transition, no input signal)]. Units are expressed in dB. Note 5: Cb = total capacitance of one bus line in pF.
_______________________________________________________________________________________
7
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Typical Operating Characteristics
(VDD = PVDD = SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD (SSM), speaker gain = 12dB.)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (SPEAKER MODE)
MAX9702 toc01
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (SPEAKER MODE)
MAX9702 toc02
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (SPEAKER MODE)
VCC = 3.3V RL = 4
MAX9702 toc03
10 VDD = 5V RL = 4
10 VDD = 5V RL = 8
10
1 THD+N (%) THD+N (%) OUTPUT POWER = 1.6W
1 THD+N (%)
1 OUTPUT POWER = 400mW
OUTPUT POWER = 800mW 0.1
0.1 OUTPUT POWER = 200mW
0.1 OUTPUT POWER = 100mW OUTPUT POWER = 200mW
0.01 10 100 1k FREQUENCY (Hz) 10k 100k
0.01 10 100 1k FREQUENCY (Hz) 10k 100k
0.01 10 100 1k FREQUENCY (Hz) 10k 100k
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (SPEAKER MODE)
MAX9702 toc04
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (SPEAKER MODE)
MAX9702 toc05
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (SPEAKER MODE)
VDD = 5V RL = 4 10
MAX9702 toc06
10 VCC = 3.3V RL = 8
10 VDD = 5V RL = 8 POUT = 800mW 1 THD+N (%)
100
1 THD+N (%)
THD+N (%)
OUTPUT POWER = 400mW 0.1 OUTPUT POWER = 100mW 0.01 10 100 1k FREQUENCY (Hz) 10k 100k
FFM 0.1
1
fIN = 20Hz
0.1 SSM 0.01 10 100 1k FREQUENCY (Hz) 10k 100k 0.01 0 0.5 1.0 1.5 2.0 2.5 OUTPUT POWER (W) fIN = 1kHz fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (SPEAKER MODE)
MAX9702 toc07
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (SPEAKER MODE)
MAX9702 toc08
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (SPEAKER MODE)
VDD = 3.3V RL = 8 10 THD+N (%)
MAX9702 toc09
100 VDD = 5V RL = 8 10 THD+N (%)
100 VDD = 3.3V RL = 4 10 THD+N (%)
100
1 fIN = 10kHz 0.1 fIN = 20Hz 0.01 0 300 600 900 1200 1500 OUTPUT POWER (mW) fIN = 1kHz
1
fIN = 20Hz
1 fIN = 10kHz fIN = 20Hz 0.1
0.1 fIN = 1kHz 0.01 0 200 400 600
fIN = 10kHz
0.01 800 1000 0 100 200 300 OUTPUT POWER (mW)
fIN = 1kHz 400 500 600 700
OUTPUT POWER (mW)
8
_______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Typical Operating Characteristics (continued)
(VDD = PVDD = SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD (SSM), speaker gain = 12dB.)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (SPEAKER MODE)
MAX9702 toc10
EFFICIENCY vs. OUTPUT POWER (SPEAKER MODE)
MAX9702 toc11
EFFICIENCY vs. OUTPUT POWER (SPEAKER MODE)
90 80 EFFICIENCY (%) 70 60 50 40 30 RL = 4 RL = 8
MAX9702 toc12
100 VDD = 5V RL = 8 fIN = 1kHz
100 90 80 EFFICIENCY (%) 70 60 50 40 30 RL = 4 RL = 8
100
10
THD+N (%)
1 SSM 0.1 FFM
0.01
20 10
VDD = 5V fIN = 1kHz POUT = POUTL + POUTR 0 0.5 1.0 1.5 2.0 2.5 3.0
20 10 0 0 0.2 0.4
VDD = 3.3V fIN = 1kHz POUT = POUTL + POUTR 0.6 0.8 1.0
0.001 0 300 600 900 1200 1500 OUTPUT POWER (mW)
0 OUTPUT POWER (W)
OUTPUT POWER (W)
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9702 toc13
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9702 toc14
OUTPUT POWER vs. LOAD RESISTANCE
VDD = 5V f = 1kHz 2.0 OUTPUT POWER (W) THD+N = 10%
MAX9702 toc15
3000 2500 OUTPUT POWER (mW) 2000 1500 1000 500 0 2.5 3.0 3.5 4.0 4.5 5.0 RL = 4 fIN = 1kHz THD+N = 10%
2000 RL = 8 fIN = 1kHz OUTPUT POWER (mW) 1500 THD+N = 10%
2.5
1.5
1000 THD+N = 1% 500
1.0 THD+N = 1% 0.5
THD+N = 1%
0 5.5 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V)
0 1 10 LOAD RESISTANCE () 100
OUTPUT POWER vs. LOAD RESISTANCE
MAX9702 toc16
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY (SPEAKER MODE)
MAX9702 toc17
CROSSTALK vs. FREQUENCY (SPEAKER MODE)
-10 -20 CROSSTALK (dB) -30 -40 -50 -60 -70 -80 LEFT TO RIGHT VRIPPLE = 100mVP-P VDD = 3.3V, 5V RL = 8
MAX9702 toc18
1000 VDD = 3.3V f = 1kHz 800 OUTPUT POWER (mW) THD+N = 10%
0 -10 -20 -30 PSRR (dB) VRIPPLE = 100mVP-P RL = 8
0
600
-40 -50 -60 -70 VDD = 3.3V
400
THD+N = 1%
200
-80 -90 VDD = 5V 10 100 1k FREQUENCY (Hz) 10k 100k
-90 -100 10 100
RIGHT TO LEFT 1k FREQUENCY (Hz) 10k 100k
0 1 10 LOAD RESISTANCE () 100
-100
_______________________________________________________________________________________
9
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Typical Operating Characteristics (continued)
(VDD = PVDD = SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD (SSM), speaker gain = 12dB.)
CROSSTALK vs. AMPLITUDE (SPEAKER MODE)
MAX9702 toc19
OUTPUT FREQUENCY SPECTRUM (SPEAKER MODE)
MAX9702 toc20
OUTPUT FREQUENCY SPECTRUM (SPEAKER MODE)
FFM MODE VOUT = -60dBV f = 1kHz RL = 8 A-WEIGHTED
MAX9702 toc21
0 -10 -20 CROSSTALK (dB) -30 -40 -50 -60 -70 -80 -90 -100 -60 -50 -40 -30 -20 -10 0 AMPLITUDE (dB) LEFT TO RIGHT RL = 8 f = 1kHz
0 -20 OUTPUT MAGNITUDE (dBV) -40 -60 -80 -100 -120 FFM MODE VOUT = -60dBV f = 1kHz RL = 8 UNWEIGHTED
0 -20 OUTPUT MAGNITUDE (dBV) -40 -60 -80 -100 -120 -140
RIGHT TO LEFT -140 0 5 10 FREQUENCY (kHz) 15 20 0 5 10 FREQUENCY (kHz) 15 20
OUTPUT FREQUENCY SPECTRUM (SPEAKER MODE)
MAX9702 toc22
OUTPUT FREQUENCY SPECTRUM (SPEAKER MODE)
MAX9702 toc23
WIDEBAND OUTPUT SPECTRUM (FFM MODE, SPEAKER MODE)
0 OUTPUT AMPLITUDE (dBV) -10 -20 -30 -40 -50 -60 -70 RBW = 10kHz INPUT AC GROUNDED
MAX9702 toc24 MAX9702 toc27
0 -20 OUTPUT MAGNITUDE (dBV) -40 -60 -80 -100 -120 -140 0 5 10 FREQUENCY (kHz) 15 SSM MODE VOUT = -60dBV f = 1kHz RL = 8 UNWEIGHTED
0 -20 OUTPUT MAGNITUDE (dBV) -40 -60 -80 -100 -120 -140 SSM MODE VOUT = -60dBV f = 1kHz RL = 8 A-WEIGHTED
10
-80 -90 0 5 10 FREQUENCY (kHz) 15 20 1 10 100 1000 FREQUENCY (MHz)
20
WIDEBAND OUTPUT SPECTRUM (SSM MODE, SPEAKER MODE)
0 OUTPUT AMPLITUDE (dBV) -10 -20 -30 -40 -50 -60 -70 -80 -90 1 10 100 1000 FREQUENCY (MHz) MAX9702 OUTPUT RBW = 10kHz INPUT AC GROUNDED
MAX9702 toc25
TURN-ON/TURN-OFF RESPONSE (SPEAKER MODE)
MAX9702 toc26
SUPPLY CURRENT vs. SUPPLY VOLTAGE (SPEAKER MODE)
20
10
17 SUPPLY CURRENT (mA) SHDN SSM
14
11 FFM 8
f = 1kHz RL = 8 20ms/div
5 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V)
10
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Typical Operating Characteristics (continued)
(VDD = PVDD = SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD (SSM), speaker gain = 12dB.)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (HEADPHONE MODE)
MAX9702 toc29
SHUTDOWN CURRENT vs. SUPPLY VOLTAGE (SPEAKER MODE)
MAX9702 toc28
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (HEADPHONE MODE)
VDD = 3.3V RL = 16 1 THD+N (%) OUTPUT POWER = 15mW 0.1
MAX9702 toc30
0.20
10 VDD = 5V RL = 32 1 THD+N (%)
10
SHUTDOWN CURRENT (A)
0.15
0.10
0.1
OUTPUT POWER = 10mW
0.05
0.01 OUTPUT POWER = 30mW
0.01 OUTPUT POWER = 40mW 0.001 10 100 1k FREQUENCY (Hz) 10k 100k 10 100 1k FREQUENCY (Hz) 10k 100k
0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V)
0.001
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (HEADPHONE MODE)
MAX9702 toc31
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (HEADPHONE MODE)
MAX9702 toc32
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (HEADPHONE MODE)
VDD = 3.3V RL = 16 10
MAX9702 toc33
10 VDD = 3.3V RL = 32 1 THD+N (%)
100 VDD = 5V RL = 32 10
100
THD+N (%)
1 fIN = 1kHz fIN = 10kHz
THD+N (%)
1 fIN = 10kHz 0.1 fIN = 1kHz
0.1
OUTPUT POWER = 10mW
0.1
0.01 OUTPUT POWER = 30mW 0.001 10 100 1k FREQUENCY (Hz) 10k 100k
0.01 fIN = 20Hz
0.01 fIN = 20Hz 0 10 20 30 40 50 60
0.001 0 10 20 30
0.001 40 50 60 OUTPUT POWER (mW)
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (HEADPHONE MODE)
MAX9702 toc34
POWER DISSIPATION vs. OUTPUT POWER (HEADPHONE MODE)
MAX9702 toc35
POWER DISSIPATION vs. OUTPUT POWER (HEADPHONE MODE)
175 POWER DISSIPATION (mW) 150 125 100 75 50 25 0 RL = 32 RL = 16 VDD = 3.3V POUT = POUTR + POUTL
MAX9702 toc36
100 VDD = 3.3V RL = 32 10
350 300 POWER DISSIPATION (mW) 250 200 150 100 50 VDD = 5V RL = 32 POUT = POUTR + POUTL
200
THD+N (%)
1 fIN = 1kHz
0.1
fIN = 10kHz
0.01 fIN = 20Hz 0 0 10 20 30 40 50 60 0 30 60 90 120 150 OUTPUT POWER (mW) OUTPUT POWER (mW)
0.001
0
30
60
90
120
150
OUTPUT POWER (mW)
______________________________________________________________________________________
11
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Typical Operating Characteristics (continued)
(VDD = PVDD = SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD (SSM), speaker gain = 12dB.)
OUTPUT POWER vs. SUPPLY VOLTAGE (HEADPHONE MODE)
MAX9702 toc37
OUTPUT POWER vs. LOAD RESISTANCE (HEADPHONE MODE)
MAX9702 toc38
OUTPUT POWER vs. LOAD RESISTANCE (HEADPHONE MODE)
VDD = 3.3V f = 1kHz
MAX9702 toc39 MAX9702 toc42
80 RL = 32 70 THD+N = 10% OUTPUT POWER (mW) 60 50 40 30 20 10 0 2.5 3.0 3.5 4.0 4.5 5.0 THD+N = 1%
70 60 OUTPUT POWER (mW) 50 40 THD+N = 10% 30 20 THD+N = 1% 10 0 VDD = 5V f = 1kHz
70 60 OUTPUT POWER (mW) 50 40 30 20 10 0
THD+N = 10% THD+N = 1%
5.5
10
100 LOAD RESISTANCE ()
1000
10
100 LOAD RESISTANCE ()
1000
SUPPLY VOLTAGE (V)
OUTPUT POWER vs. CHARGE-PUMP CAPACITANCE (HEADPHONE MODE)
MAX9702 toc40
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY (HEADPHONE MODE)
MAX9702 toc41
OUTPUT FREQUENCY SPECTRUM (HEADPHONE MODE)
0 -20 OUTPUT MAGNITUDE (dBV) -40 -60 -80 -100 -120 VOUT = -60dBV f = 1kHz RL = 32
60 55 OUTPUT POWER (mW) 50 f = 1kHz THD+N = 1%
0 -10 -20 -30 PSRR (dB) -40 -50 -60 -70 -80 VDD = 3.3V VRIPPLE = 100mVP-P INPUTS AC GROUNDED
45 40 C1 = C2 = 0.47F 35 30 25 20 15 20 25 30 35
C1 = C2 = 1F
-90 40 45 50 -100 10 100
VDD = 5V -140 1k FREQUENCY (Hz) 10k 100k 0 5 10 FREQUENCY (kHz) 15 20
LOAD ()
CROSSTALK vs. FREQUENCY (HEADPHONE MODE)
MAX9702 toc43
CROSSTALK vs. AMPLITUDE (HEADPHONE MODE)
-10 -20 CROSSTALK (dBV) -30 -40 -50 -60 -70 -80 -90 -100 -110 100k -60 -50 -40 -30 -20
LEFT TO RIGHT RIGHT TO LEFT
TURN-ON/TURN-OFF RESPONSE (HEADPHONE MODE)
MAX9702 toc45 MAX9702 toc44
0 -10 -20 -30 CROSSTALK (dB) -40 -50 -60 -70 -80 -90 -100 -110 10 100 1k FREQUENCY (Hz) 10k
LEFT TO RIGHT RIGHT TO LEFT
0 RL = 32 f = 1kHz
RL = 32 f = 1kHz VIN = 100mVP-P
SHDN
MAX9702 OUTPUT
f = 1kHz RL = 32 10 100ms/div
-10
0
AMPLITUDE (dBV)
12
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Pin Description
PIN TQFN 1, 22 2 3 4 5 TSSOP 4, 25 5 6 7 8 NAME PVDD SYNC_OUT SCL SDA BIAS FUNCTION H-Bridge Power Supply. Connect to VDD and bypass each PVDD with a 0.1F capacitor to PGND. Clock Signal Output. Float SYNC_OUT if not used. I2C Serial Clock. Connect a pullup resistor to VDD (see I2C Interface section). I2C Serial Data. Connect a pullup resistor to VDD (see I2C Interface section). Common-Mode Voltage. Bypass to GND with a 1F capacitor. Frequency Mode Select: SYNC = GND: Fixed-frequency mode with fS = 1100kHz. SYNC = Float: Fixed-frequency mode with fS = 1340kHz. SYNC = VDD: Spread-spectrum mode with fS = 1150kHz 50kHz. SYNC = Clocked: Fixed-frequency mode with fS = external clock frequency. Charge-Pump Power Supply. Connect to VDD and bypass to CPGND with a 1F capacitor. Charge-Pump Flying-Capacitor Positive Terminal. Connect a 1F capacitor from C1P to C1N. Charge-Pump Power Ground. Connect to PGND. Charge-Pump Flying-Capacitor Negative Terminal. Connect a 1F capacitor from C1N to C1P. Charge-Pump Negative Output. Bypass with a 1F capacitor to CPGND. Headphone Amplifier Negative Supply. Connect to CPVSS. Left-Channel Headphone Output Right-Channel Headphone Output Analog Power Supply. Bypass with a 1F capacitor to GND. Analog Ground. Connect to PGND. Right-Channel Audio Input Left-Channel Audio Input Mono Audio Input Headphone Sense: HPS = VDD: Headphone mode. HPS = GND: Speaker mode. Active-Low Shutdown. Connect to VDD for normal operation. Right-Channel Positive Amplifier Output Right-Channel Negative Amplifier Output Power Ground. Connect to GND. Left-Channel Negative Amplifier Output Left-Channel Positive Amplifier Output Exposed Pad. The external pad lowers the package's thermal impedance by providing a direct heat conduction path from the die to the printed circuit board. The exposed pad is internally connected to VSS. Connect the exposed thermal pad to an isolated plane if possible or VSS.
MAX9702
6
9
SYNC
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 23 24 25, 26 27 28
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 27 1, 28 2 3
CPVDD C1P CPGND C1N CPVSS VSS HPL HPR VDD GND INR INL INM HPS SHDN OUTR+ OUTRPGND OUTLOUTL+
EP
--
EP
______________________________________________________________________________________
13
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Detailed Description
The MAX9702 is a 1.8W, filterless, stereo Class D audio power amplifier and DirectDrive stereo headphone amplifier. The MAX9702 SSM amplifier features significant improvements to switch-mode amplifier technology. The MAX9702 offers Class AB performance with Class D efficiency and minimal board space. The device offers mix, mute, mono and stereo input modes, eight selectable gains, and a low-power shutdown mode--all programmable through an I2C interface. The MAX9702 stereo headphone amplifier features Maxim's patented DirectDrive architecture, which eliminates the large output-coupling capacitors required by conventional single-supply headphone amplifiers. A negative supply (VSS) is created internally by inverting the positive supply (CPVDD). Powering the amplifiers from CPVDD and CPVSS increases the dynamic range of the amplifiers to almost twice that of other single-supply amplifiers, increasing the total available output power. The DirectDrive outputs of the MAX9702 are biased at GND (see Figure 7). The benefit of this 0V bias is that the amplifier outputs do not have a DC component, eliminating the need for large DC-blocking capacitors. Eliminating the DC-blocking capacitors on the output saves board space, system cost, and improves frequency response. The MAX9702 features extensive click-and-pop suppression circuitry on both speaker and headphone amplifiers to eliminate audible clicks-and-pops on startup and shutdown. The MAX9702 features an input multiplexer/mixer that allows three different audio sources to be selected or mixed. An I2C-compatible interface allows serial communication between the MAX9702 and a microcontroller. The MAX9702 is available with two different I2C addresses allowing two MAX9702s to share the same bus (see Table 2). The internal command register controls the shutdown status of the MAX9702, sets the maximum gain of the amplifier, and controls the mono/stereo/mixed/mute MUX inputs (see Table 3). rising edge of the second comparator trip point, generating a minimum-width pulse (tON(MIN),100ns typ) at the output of the second comparator (Figure 1). As the input voltage increases or decreases, the duration of the pulse at one output increases while the other output pulse duration remains the same. This causes the net voltage across the speaker (VOUT+ - VOUT-) to change. The minimum-width pulse helps the device to achieve high levels of linearity.
Operating Modes
Fixed-Frequency (FFM) Mode The MAX9702 features two fixed-frequency modes. Connect SYNC to GND to select a 1.1MHz switching frequency. Float SYNC to select a 1.34MHz switching frequency. The frequency spectrum of the MAX9702 consists of the fundamental switching frequency and its associated harmonics (see the Wideband FFT graph in Typical Operating Characteristics). Program the switching frequency such that the harmonics do not fall within a sensitive frequency band (Table 1). Audio reproduction is not affected by changing the switching frequency. Spread-Spectrum (SSM) Mode The MAX9702 features a unique, patented spreadspectrum mode that flattens the wideband spectral components, improving EMI emissions that may be radiated by the speaker and cables. This mode is enabled by setting SYNC = VDD to enable SSM (Table 1). In SSM mode, the switching frequency varies randomly by 50kHz around the center frequency (1.15MHz). The modulation scheme remains the same, but the period of the sawtooth waveform changes from cycle to cycle (Figure 2). Instead of a large amount of spectral energy present at multiples of the switching frequency, the energy is now spread over a bandwidth that increases with frequency. Above a few megahertz, the wideband spectrum looks like white noise for EMI purposes (Figure 3). A proprietary amplifier topology ensures this does not corrupt the noise floor in the audio bandwidth.
Class D Speaker Amplifier
Spread-spectrum modulation and synchronizable switching frequency significantly reduce EMI emissions. Comparators monitor the audio inputs and compare the complementary input voltages to a sawtooth waveform. The comparators trip when the input magnitude of the sawtooth exceeds their corresponding input voltage. Both comparators reset at a fixed time after the
Table 1. Operating Modes
SYNC GND FLOAT VDD Clocked MODE FFM with fOSC = 1100kHz FFM with fOSC = 1340kHz SSM with fOSC = 1150kHz 50kHz FFM with fOSC = external clock frequency
14
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
tSW
VIN-
VIN+
OUT-
OUT+
tON(MIN)
VOUT+ - VOUT-
Figure 1. MAX9702 Outputs with an Input Signal Applied
______________________________________________________________________________________
15
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
tSW tSW tSW tSW
VIN_-
VIN_+
OUT_-
OUT_+
tON(MIN)
VOUT_+ - VOUT_-
Figure 2. MAX9702 Output with an Input Signal Applied (SSM Mode)
16
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
MAX9702 fig03
50 45 AMPLITUDE (dBV/m) 40 35 30 25 20 15 30 60 80 100 120 140 160 180 200 220 240 260 280 MAX9702 FCC EMI LIMIT
300
FREQUENCY (MHz)
Figure 3. MAX9702 EMI with 76mm of Speaker Cable
External Clock Mode The SYNC input allows the MAX9702 to be synchronized to an external clock, or another Maxim Class D amplifier, creating a fully synchronous system, minimizing clock intermodulation, and allocating spectral components of the switching harmonics to insensitive frequency bands. Applying a TTL clock signal between 1MHz and 2MHz to SYNC synchronizes the MAX9702. The period of the SYNC clock can be randomized, allowing the MAX9702 to be synchronized to another Maxim Class D amplifier operating in SSM mode. SYNC_OUT allows several Maxim Class D amplifiers to be cascaded. The synchronized output minimizes interference due to clock intermodulation caused by the switching spread between single devices using SYNC_OUT. The modulation scheme remains the same when using SYNC_OUT, and audio reproduction is not affected (see Figure 4).
OUTL+ OUTL-
MAX9702
SYNC INPUT SYNC
OUTR+ OUTR-
SYNC_OUT
MAX9700
OUT+ SYNC OUT-
Figure 4. Cascading Two Amplifiers
______________________________________________________________________________________
17
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Filterless Modulation/Common-Mode Idle
The MAX9702 uses Maxim's unique, patented modulation scheme that eliminates the LC filter required by traditional Class D amplifiers, improving efficiency, reducing component count, conserving board space and system cost. Conventional Class D amplifiers output a 50% dutycycle square wave when no signal is present. With no filter, the square wave appears across the load as a DC voltage, resulting in finite load current, increasing power consumption, especially when idling. When no signal is present at the input of the MAX9702, the outputs switch as shown in Figure 5. Because the MAX9702 drives the speaker differentially, the two outputs cancel each other, resulting in no net idle mode voltage across the speaker, minimizing power consumption.
Efficiency
Efficiency of a Class D amplifier is due to the switching operation of the output stage transistors. In a Class D amplifier, the output transistors act as current-steering switches and consume negligible additional power. Any power loss associated with the Class D output stage is mostly due to the I2R loss of the MOSFET onresistance, and quiescent current overhead. The theoretical best efficiency of a linear amplifier is 78%; however, that efficiency is only exhibited at peak output powers. Under normal operating levels (typical music reproduction levels), efficiency falls below 30%, whereas the MAX9702 still exhibits >80% efficiencies under the same conditions (Figure 6).
EFFICIENCY vs. OUTPUT POWER
VIN_ = 0V
100 90 80 EFFICIENCY (%) 70 60 50 40 30 VDD = 5V fIN = 1kHz RL = 8 0 0.1 0.2 0.3 0.4 0.5 CLASS AB MAX9702
OUT_-
OUT_+
20 10 0
OUTPUT POWER (W)
VOUT_+ - VOUT_- = 0V
Figure 5. MAX9702 Outputs with No Input Signal
Figure 6. MAX9702 Efficiency vs. Class AB Efficiency
18
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Headphone Amplifier
In conventional single-supply headphone 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, during shutdown the capacitor is discharged to GND. This results in DC shift across the capacitor, which in turn, appears as an audible transient at the speaker. Since the MAX9702 headphone amplifier does not require output-coupling capacitors, this does not arise. The MAX9702 offers four headphone amplifier gain settings controlled through the I2C interface. Headphone amplifier gains of -2dB, +1dB, +4dB, and +7dB are set by command register bits 3 and 4 (Table 5). Additionally, the MAX9702 features extensive click-andpop suppression that eliminates any audible transient sources internal to the device. In most applications, the output of the preamplifier driving the MAX9702 has a DC bias of typically half the supply. During startup, the input-coupling capacitor is charged to the preamplifier's DC bias voltage through the RF of the MAX9702, resulting in a DC shift across the capacitor and an audible click-and-pop. An internal delay of 40ms eliminates the clicks-and-pops caused by the input filter. Resistance graph in the Typical Operating Characteristics for details of the possible capacitor sizes. There is a low DC voltage on the driver outputs due to amplifier offset. However, the offset of the MAX9702 is typically 1.1mV, which, when combined with a 32 load, results in less than 56A of DC current flow to the headphones. In addition to the cost and size disadvantages of the DC-blocking capacitors required by conventional headphone amplifiers, these capacitors limit the amplifier's low-frequency response and can distort the audio signal. Previous attempts at eliminating the output-coupling capacitors involved biasing the headphone return (sleeve) to the DC bias voltage of the headphone amplifiers. This method raises some issues: 1) The sleeve is typically grounded to the chassis. Using the midrail biasing approach, the sleeve must be isolated from system ground, complicating product design. 2) During an ESD strike, the driver's ESD structures are the only path to system ground. Thus, the driver must be able to withstand the full ESD strike. 3) 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 drivers.
MAX9702
DirectDrive
Traditional single-supply headphone amplifiers have outputs biased at 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 headphone and headphone amplifier. Maxim's patented DirectDrive architecture uses a charge pump to create an internal negative supply voltage. This allows the headphone outputs of the MAX9702 to be biased at GND, almost doubling dynamic range while operating from a single supply. With no DC component, there is no need for the large DC-blocking capacitors. Instead of two large (220F, typ) tantalum capacitors, the MAX9702 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
VDD VDD/2 GND CONVENTIONAL AMPLIFIER BIASING SCHEME +VDD
GND
-VDD DirectDrive BIASING SCHEME
Figure 7. Traditional Amplifier Output vs. MAX9702 DirectDrive Output
______________________________________________________________________________________
19
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Charge Pump The MAX9702 features a low-noise charge pump. The switching frequency of the charge pump is 1/2 the switching frequency of the Class D amplifier. When SYNC is driven externally, the charge pump switches at 1/2 fSYNC. When SYNC = VDD, the charge pump switches with a spread-spectrum pattern. The nominal switching frequency is well beyond the audio range, and thus does not interfere with the audio signals, resulting in an SNR of 97dB. 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 highfrequency noise attenuation can be achieved by increasing the size of C2 (see Typical Application Circuit). The charge pump is active in both speaker and headphone modes. Input Multiplexer/Mixer The MAX9702 features an input multiplexer/mixer that allows three different audio sources to be selected and mixed. Command register bits 5 and 6 select the input channel (see Table 6), and the audio signal is output to the active amplifier. When the mono path is selected (bit 6 = 0, bit 5 = 1), the mono input is present on both the outputs (with a gain according to Tables 4 and 5). When the stereo path is selected, the left and right inputs are present on the outputs (with a gain according to Tables 4 and 5). When in mixer mode, the mono input is added to each of the stereo inputs and present at the output (with a gain according to Tables 4 and 5). The mono and stereo signals are attenuated by 6dB prior to mixing to maintain dynamic range. In mute, none of input signals is present at output. Headphone Sense Input (HPS) The headphone sense input (HPS) monitors the headphone jack, and automatically configures the MAX9702 based on the voltage applied at HPS. A voltage of less than 0.8V sets the MAX9702 to speaker mode. A voltage of greater than 2V disables the bridge amplifiers and enables the headphone amplifiers. For automatic headphone detection, connect HPS to the control pin of a 3-wire headphone jack as shown in Figure 8. With no headphone present, the output impedance of the headphone amplifier pulls HPS to less than 0.8V. When a headphone plug is inserted into the jack, the control pin is disconnected from the tip
MAX9702
contact and HPS is pulled to VDD through the internal 600k pullup resistor. When driving HPS from an external logic source, drive HPS low when the MAX9702 is shut down. Place a 10k resistor in series with HPS and the headphone jack to ensure 8kV ESD protection.
Click-and-Pop Suppression
The MAX9702 features comprehensive click-and-pop suppression that eliminates audible transients on startup and shutdown. While in shutdown, the H-bridge is in a high-impedance state. During startup or power-up, the input amplifiers are muted and an internal loop sets the modulator bias voltages to the correct levels, preventing clicks and pops when the H-bridge is subsequently enabled.
Current-Limit and Thermal Protection
The MAX9702 features current limiting and thermal protection to protect the device from short circuits and overcurrent conditions. The headphone amplifier pulses in the event of an overcurrent condition. The speaker amplifiers' current-limiting protection clamps the output current without shutting down the outputs. This can result in a distorted output. The MAX9702 has thermal protection that disables the device into shutdown at +120C until the temperature decreases to +110C.
VDD MAX9702 100k SHUTDOWN CONTROL HPS I2C CONTROL HPL HPR 10k 10k
SHDN
SDA SCL
Figure 8. HPS Configuration
20
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
SDA tSU, DAT tLOW SCL tHD, STA tR START CONDITION tHIGH tF REPEATED START CONDITION STOP CONDITION START CONDITION tHD, DAT tSU, STA tBUF tHD, STA tSP tSU, STO
Figure 9. 2-Wire Serial-Interface Timing Diagram
S
Sr
P
SCL
SDA
dition. Each word transmitted over the bus is 8 bits long and is always followed by an acknowledge clock pulse. The MAX9702 SDA line operates as both an input and an open-drain output. A pullup resistor, greater than 500, is required on the SDA bus. The MAX9702 SCL line operates as an input only. A pullup resistor, greater than 500, is required on SCL if there are multiple masters on the bus, or if the master in a single-master system has an open-drain SCL output. Series resistors in line with SDA and SCL are optional. Series resistors protect the digital inputs of the MAX9702 from highvoltage spikes on the bus lines, and minimize crosstalk and undershoot of the bus signals. Bit Transfer One data bit is transferred during each SCL cycle. The data on SDA must remain stable during the high period of the SCL pulse. Changes in SDA while SCL is high are control signals (see the START and STOP Conditions section). SDA and SCL idle high when the I2C bus is not busy. START and STOP Conditions A master device initiates communication by issuing a START condition. A START condition is a high-to-low transition on SDA with SCL high. A STOP condition is a low-to-high transition on SDA while SCL is high (Figure 10). A START (S) condition from the master signals the beginning of a transmission to the MAX9702. The master terminates transmission and frees the bus by issuing a STOP (P) condition. The bus remains active if a REPEATED START (Sr) condition is generated instead of a STOP condition.
21
Figure 10. START, STOP, and REPEATED START Conditions
I2C Interface
The MAX9702 features an I 2C 2-wire serial interface consisting of a serial data line (SDA) and a serial clock line (SCL). SDA and SCL facilitate communication between the MAX9702 and the master at clock rates up to 400kHz. Figure 9 shows the 2-wire interface timing diagram. The MAX9702 is a receive-only slave device relying on the master to generate the SCL signal. The MAX9702 cannot write to the SDA bus except to acknowledge the receipt of data from the master. The MAX9702 does not acknowledge a read command from the master. The master, typically a microcontroller, generates SCL and initiates data transfer on the bus. A master device communicates to the MAX9702 by transmitting the proper address followed by the data word. Each transmit sequence is framed by a START (S) or REPEATED START (Sr) condition and a STOP (P) con-
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
Early STOP Conditions The MAX9702 recognizes a STOP condition at any point during data transmission except if the STOP condition occurs in the same high pulse as a START condition. Slave Address The MAX9702 is available with one of two preset slave addresses (see Table 2). The address is defined as the 7 most significant bits (MSBs) followed by the Read/Write bit. The address is the first byte of information sent to the MAX9702 after the START condition. The MAX9702 is a slave device only capable of being written to. The Read/Write bit must always be a zero when configuring the MAX9702. The MAX9702 does not acknowledge the receipt of its address even if R/W is set to 1. Acknowledge The acknowledge bit (ACK) is a clocked 9th bit that the MAX9702 uses to handshake receipt each byte of data (see Figure 11). The MAX9702 pulls down SDA during the master-generated 9th clock pulse. The SDA line must remain stable and low during the high period of the acknowledge clock pulse. Monitoring ACK allows for detection of unsuccessful data transfers. An unsuccessful data transfer occurs if a receiving device is busy or if a system fault has occurred. In the event of an unsuccessful data transfer, the bus master may reattempt communication. Write Data Format A write to the MAX9702 includes transmission of a START condition, the slave address with the R/W bit set to zero (see Table 2), 1 byte of data to configure the command register, and a STOP condition. Figure 12 illustrates the proper format for one frame.
START CONDITION SCL 1 2 CLOCK PULSE FOR ACKNOWLEDGMENT
8 NOT ACKNOWLEDGE
9
SDA ACKNOWLEDGE
Figure 11. Acknowledge
COMMAND BYTE IS STORED ON RECEIPT OF STOP CONDITION ACKNOWLEDGE FROM MAX9702 S SLAVE ADDRESS R/W 0
B7 B6 B5 B4 B3 B2 B1 B0
A COMMAND BYTE ACKNOWLEDGE FROM MAX9702
AP
Figure 12. Write Data Format Example
The MAX9702 only accepts write data, but it acknowledges the receipt of its address byte with the R/W bit set high. The MAX9702 does not write to the SDA bus in the event that the R/W bit is set high. Subsequently, the master reads all 1s from the MAX9702. Always set the R/W bit to zero to avoid this situation.
Table 2. MAX9702 Address Map
PART MAX9702 MAX9702B MAX9702 SLAVE ADDRESS A6 1 1 A5 0 0 A4 0 0 A3 1 1 A2 1 1 A1 0 1 A0 0 0 R/W 0 0
22
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Command Register The MAX9702 has one command register that is used to set speaker and headphone gain, select an input mode, and enable/disable shutdown. Table 3 describes the function of the bits contained in the command register. Programmable Speaker Gain The MAX9702 has eight internally set speaker gains selected by B0-B2 (see Table 4). Programmable Headphone Gain The MAX9702 has four headphone gain settings selected by B3 and B4 (see Table 5). Programmable Input Modes The MAX9702 features a multiplexer that selects between the stereo and mono inputs. The mux also acts as a mixer when the mono and stereo inputs are enabled at the same time. The MUTE function disables the input signal to the output. All modes are selected through B5 and B6 (see Table 6). The MIX function attenuates and mixes the MONO and STEREO signals. Each input signal is attenuated by 6dB prior to being mixed. This attenuation preserves headroom at the output. The output signal is represented by the following equation when in MIX mode:
MAX9702
(OUT _ + (-)OUT _ _ ) or HP _ = IN _ + INM x A V 2
where AV is the amplifier gain.
Table 3. Command Bits and Description
BIT B0 B1 B2 B3 B4 B5 B6 B7 FUNCTION Speaker gain-setting bit Speaker gain-setting bit Speaker gain-setting bit Headphone gain-setting bit Headphone gain-setting bit MONO enable bit (0 = Mute) STEREO enable bit (0 = Mute) Shutdown bit (1 = normal, 0 = shutdown) DEFAULT 0 0 1 1 0 0 1 1
Table 5. Programmable Headphone Gain
B4 0 0 1 1 B3 0 1 0 1 FUNCTION Headphone gain Headphone gain (default) Headphone gain Headphone gain GAIN (dB) -2 +1 +4 +7
Table 6. Programmable Input Modes
B6 0 0 1 1 B5 0 1 0 1 FUNCTION MUTE (no input on the output) MONO (MONO input sent to the output) STEREO (left and right inputs sent to the outputs) (default) MIX (MONO and STEREO inputs are mixed and output)
Table 4. Programmable Speaker Gain
B2 0 0 0 0 1 1 1 1 B1 0 0 1 1 0 0 1 1 B0 0 1 0 1 0 1 0 1 FUNCTION Speaker gain Speaker gain Speaker gain Speaker gain Speaker gain Speaker gain Speaker gain Speaker gain GAIN (dB) +0 +3 +6 +9 +12 +15 +18 +21
______________________________________________________________________________________
23
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Shutdown The MAX9702 features a 0.1A shutdown mode that reduces power consumption to extend battery life. Shutdown is controlled by the hardware or software interface. Drive SHDN low to disable the drive amplifiers, bias circuitry, charge pump, and set the headphone amplifier output impedance to 1k. Similarly, the MAX9702 enters shutdown when bit 7 (B7) in the control register is set to zero. Connect SHDN to VDD and set bit 7 = 1 for normal operation (see Table 7). The I2C interface is active and the contents of the command register are not affected when in shutdown. This allows the master to write to the MAX9702 while in shutdown.
MAX9702
example, an 8mV DC offset across an 8 load results in 1mA extra current consumption in a Class AB device. In the Class D case, an 8mV offset into 8 equates to an additional power drain of 8W. Due to the high efficiency of the Class D amplifier, this represents an additional quiescent current draw of 8W/(V DD /100 x ), which is on the order of a few microamps.
DC-Coupled Input
The input amplifier can accept DC-coupled inputs that are biased to the amplifier's bias voltage. DC-coupling eliminates the input-coupling capacitors, reducing component count to potentially one external component (see the System Diagram). However, the highpass filtering effect of the capacitors is lost, allowing low-frequency signals to feed through to the load.
Table 7. Shutdown Control (SHDN)
B7 0 1 Soft shutdown Normal operation FUNCTION
Power Supplies
The MAX9702 has different supplies for each portion of the device, allowing for the optimum combination of headroom power dissipation and noise immunity. The speaker amplifiers are powered from PVDD. PVDD can range from 2.5V to 5.5V and must be connected to the same potential as VDD. The headphone amplifiers are powered from VDD and VSS. VDD is the positive supply of the headphone amplifiers and can range from 2.5V to 5.5V. VSS is the negative supply of the headphone amplifiers. Connect VSS to CPVSS. The charge pump is powered by CPVDD. Connect CPVDD to VDD for normal operation. The charge pump inverts the voltage at CPVDD, and the resulting voltage appears at CPVSS. The remainder of the device is powered by VDD.
Applications Information
Filterless Class D Operation
Traditional Class D amplifiers require an output filter to recover the audio signal from the amplifier's PWM output. The filters add cost, increase the solution size of the amplifier, and can decrease efficiency. The traditional PWM scheme uses large differential output swings 2 x VDD(P-P) and causes large ripple currents. Any parasitic resistance in the filter components results in a loss of power, lowering the efficiency. The MAX9702 does not require an output filter. The device relies on the inherent inductance of the speaker coil and the natural filtering of both the speaker and the human ear to recover the audio component of the square wave output. By eliminating the output filter, this results in a smaller, less costly, more efficient solution. Because the frequency of the MAX9702 output is well beyond the bandwidth of most speakers, voice coil movement due to the square wave frequency is very small. Although this movement is small, a speaker not designed to handle the additional power may be damaged. For optimum results, use a speaker with a series inductance >10H. Typical 8 speakers, for portable audio applications, exhibit series inductances in the range of 20H to 100H.
Component Selection
Input Filter An input capacitor, CIN, in conjunction with the input impedance of the MAX9702 forms a highpass filter that removes the DC bias from an incoming signal. The ACcoupling capacitor allows the amplifier to automatically bias the signal to an optimum DC level. Assuming zerosource impedance, the -3dB point of the highpass filter is given by: f-3dB = 1 2RINCIN
Class D Output Offset
Unlike a Class AB amplifier, the output offset voltage of Class D amplifiers does not noticeably increase quiescent current draw when a load is applied. This is due to the power conversion of the Class D amplifier. For
24
Choose CIN such that f-3dB is well below the lowest frequency of interest. Use capacitors whose dielectrics have low-voltage coefficients, such as tantalum or aluminum electrolytic. Capacitors with high-voltage coefficients, such as ceramics, may result in increased distortion at low frequencies.
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Other considerations when designing the input filter include the constraints of the overall system and the actual frequency band of interest. Although high-fidelity audio calls for a flat-gain response between 20Hz and 20kHz, portable voice-reproduction devices such as cellular phones and two-way radios need only concentrate on the frequency range of the spoken human voice (typically 300Hz to 3.5kHz). In addition, speakers used in portable devices typically have a poor response below 300Hz. Taking these two factors into consideration, the input filter may not need to be designed for a 20Hz to 20kHz response, saving both board space and cost due to the use of smaller capacitors. Output Filter The MAX9702 does not require an output filter. The device passes FCC emissions standards with 75mm of unshielded speaker cables. However, output filtering can be used if a design is failing radiated emissions due to board layout or cable length, or the circuit is near EMI-sensitive devices. Use a ferrite bead filter when radiated frequencies above 10MHz are of concern. Use an LC filter when radiated frequencies below 10MHz are of concern, or when long leads (>200mm) connect the amplifier to the speaker. Figure 13 shows optional speaker amplifier output filters.
MAX9702
22 0.033F OUTL+ OUTL800 AT 100MHz 100pF 15H 0.15F OUTLOUTL15H 0.033F 0.068F 22 0.068F
100pF OUTL+ OUTL+
MAX9702
MAX9702
100pF
MAX9702
22 0.033F 0.068F 0.15F
OUTR+ OUTR-
OUTR+ OUTR800 AT 100MHz 100pF
OUTR+ OUTR-
15H
15H 0.033F 0.068F 22
(a) TYPICAL APPLICATION <75mm OF SPEAKER CABLE.
(b) COMMON-MODE CHOKE FOR APPLICATIONS USING CABLE LENGTHS GREATER THAN 75mm.
(c) LC FILTER WHEN USING CABLE LENGTHS LONGER THAN 200mm IN APPLICATIONS THAT ARE SENSITIVE TO EMI BELOW 10MHz.
Figure 13. Optional Speaker Amplifier Output Filter
______________________________________________________________________________________
25
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
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 1F capacitor to GND. 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. Most surface-mount ceramic capacitors satisfy the ESR requirement. For best performance over the extended temperature range, select capacitors with an X7R dielectric. Table 8 lists suggested manufacturers. Flying Capacitor (C1) The value of the flying capacitor (C1) affects the 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 reduces the charge-pump output resistance to an extent. Above 1F, the on-resistance of the switches and the ESR of C1 and C2 dominate. 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. CPVDD Bypass Capacitor The CPVDD bypass capacitor (C3) lowers the output impedance of the power supply and reduces the impact of the MAX9702's charge-pump switching transients. Bypass CPVDD with C3 to PGND and place it physically close to the CPVDD and PGND. Use a value for C3 that is equal to C1.
Supply Bypassing, 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. Large traces also aid in moving heat away from the package. Proper grounding improves audio performance, minimizes crosstalk between channels, and prevents any switching noise from coupling into the audio signal. Connect PGND and GND together at a single point on the PC board. Route all traces that carry switching transients away from GND and the traces/components in the audio signal path. Connect all of the power-supply inputs (CPVDD, VDD, and PVDD) together. Bypass PVDD with a 0.1F capacitor to PGND and CPVDD with a 1F capacitor to PGND. Bypass V DD with 1F capacitor to GND. Place the bypass capacitors as close to the MAX9702 as possible. Place a bulk capacitor between PVDD and PGND, if needed. Use large, low-resistance output traces. Current drawn from the outputs increases as load impedance decreases. High-output trace resistance decreases the power delivered to the load. Large output, supply, and GND traces allow more heat to move from the MAX9702 to the air, decreasing the thermal impedance of the circuit if possible or connect to VSS. The MAX9702 thin QFN-EP package features an exposed thermal pad on its underside. This pad lowers the package's thermal impedance by providing a directheat conduction path from the die to the printed circuit board. The exposed pad is internally connected to VSS. Connect the exposed thermal pad to an isolated plane.
Table 8. Suggested Capacitor Manufacturers
SUPPLIER Taiyo Yuden TDK PHONE 800-348-2496 807-803-6100 FAX 847-925-0899 847-390-4405 WEBSITE www.t-yuden.com www.component.tdk.com
26
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Functional Diagram/Typical Operating Circuit
2.5V TO 6.5V
MAX9702
1F VDD 6 SYNC (9) 15 (18)
10F* PVDD 1, 22 (4, 25)
0.1F
2 (5) 5 (8)
VDD
OSCILLATOR AND SAWTOOTH
SYNC_OUT BIAS CBIAS 1F
CIN 1F
18 INL (21)
CIN 1F
CLASS D MODULATOR AND H-BRIDGE
28 (3) OUTL+ 18 (21) OUTL-
19 INM (22) CLASS D MODULATOR AND H-BRIDGE 23 (26) OUTR+ 24 (27) OUTR-
CIN 1F
17 INR (20)
INPUT MUX
VDD
BASEBAND PROCESSOR VDD
21 SHDN (24) 4 SDA (7) 3 SCL (6)
20 (23) HPS 13 (16) HPL I2C 14 (17) HPR
C3 1F
7 CPVDD (10) 8 C1P (11) C1 10 1F (13) C1N 9 CPGND (12)
CHARGE PUMP BIAS GENERATOR 11 12 (14) (15) CPVSS VSS C2 1F 16 (19) GND 25, 26 (1, 28) PGND MAX9702
( ) TSSOP PIN *BULK CAPACITANCE IF NEEDED
______________________________________________________________________________________
27
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
System Diagram
VDD
*CBULK 10F VDD 0.1F AUX_IN 1F VDD INL CPVDD
1F
0.1F
PVDD OUTL+ OUTL-
MAX4063 OUT
2.2k BIAS 2.2k OUT CODEC/ BASEBAND PROCESSOR
INM
MAX9702
OUTR+ OUTR-
INR
0.1F IN+ IN0.1F 4.7k 4.7k
SYNC SYNC_OUT
HPS HPL HPR
PVDD BIAS C VSS CPVSS C2 1F 1F 0.1F
C1P C1N
C1 1F *BULK CAPACITANCE IF NEEDED
28
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
Pin Configurations
TOP VIEW
SHDN GND HPS INM VDD INR INL
PGND 1 OUTL- 2 OUTL+ 3 PVDD OUTR+ OUTRPGND PGND OUTLOUTL+ 28 PGND 27 OUTR26 OUTR+ 25 PVDD 24 SHDN
MAX9702
21 22 23 24 25 26 27 28 1
PVDD
20
19
18
17
16
15 14 13 12
HPR HPL VSS CPVSS C1N CPGND C1P
PVDD 4 SYNC_OUT 5 SCL 6 SDA 7 BIAS 8 SYNC 9
MAX9702
23 HPS 22 INM 21 INL 20 INR 19 GND 18 VDD 17 HPR 16 HPL 15 VSS
MAX9702
11 10 9 8
CPVDD 10 C1P 11 CPGND 12 C1N 13 CPVSS 14
2
SYNC_OUT
3
SCL
4
SDA
5
BIAS
6
SYNC
7
CPVDD
THIN QFN
TSSOP
Chip Information
TRANSISTOR COUNT: 10,435 PROCESS: BiCMOS
______________________________________________________________________________________
29
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
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.)
QFN THIN.EPS
L
D2 D D/2 MARKING k L E/2 E2/2 E (NE-1) X e
C L C L
b D2/2
0.10 M C A B
XXXXX
E2
PIN # 1 I.D.
DETAIL A
e (ND-1) X e
e/2
PIN # 1 I.D. 0.35x45 DETAIL B
e
L1
L
C L
C L
L
e 0.10 C A 0.08 C
e
C
A1 A3 PACKAGE OUTLINE, 16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm
-DRAWING NOT TO SCALE-
21-0140
H
1
2
30
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
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.)
MAX9702
COMMON DIMENSIONS
PKG. 16L 5x5 20L 5x5 28L 5x5 32L 5x5 40L 5x5 SYMBOL MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX.
EXPOSED PAD VARIATIONS PKG. CODES T1655-1 T1655-2 T1655N-1 T2055-2 T2055-3 T2055-4 T2055-5 T2855-1 T2855-2 T2855-3 T2855-4 T2855-5 T2855-6 T2855-7 T2855-8 T2855N-1 T3255-2 T3255-3 T3255-4 T3255N-1 T4055-1
D2
MIN. NOM. MAX. MIN.
E2
NOM. MAX.
L
0.15
A A1 A3 b D E e k L
DOWN BONDS ALLOWED
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 0.02 0.05 0 0.02 0.05 0 0.02 0.05 0 0.02 0.05 0 0.02 0.05 0.20 REF. 0.20 REF. 0.25 0.30 0.35 0.25 0.30 0.35 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 0.80 BSC. 0.65 BSC. 0.25 - 0.25 0.20 REF. 0.20 0.25 0.30 4.90 5.00 5.10 4.90 5.00 5.10 0.50 BSC. 0.25 0.20 REF. 0.20 0.25 0.30 4.90 5.00 5.10 4.90 5.00 5.10 0.50 BSC. 0.25 0.20 REF. 0.15 0.20 0.25 4.90 5.00 5.10 4.90 5.00 5.10 0.40 BSC. 0.25 0.35 0.45
3.00 3.00 3.00 3.00 3.00 3.00 3.15 3.15 2.60 3.15 2.60 2.60 3.15 2.60 3.15 3.15 3.00 3.00 3.00 3.00 3.20
3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.25 3.25 2.70 3.25 2.70 2.70 3.25 2.70 3.25 3.25 3.10 3.10 3.10 3.10 3.35 3.35 2.80 3.35 2.80 2.80 3.35 2.80 3.35 3.35 3.20 3.20 3.20 3.20 3.15 3.15 2.60 3.15 2.60 2.60 3.15 2.60 3.15 3.15 3.00 3.00 3.00 3.00
3.10 3.10 3.10 3.10 3.10 3.10 3.25 3.25 2.70 3.25 2.70 2.70 3.25 2.70 3.25 3.25 3.10 3.10 3.10 3.10 3.30
3.20 3.20 3.20 3.20 3.20 3.20 3.35 3.35 2.80 3.35 2.80 2.80 3.35 2.80 3.35 3.35 3.20 3.20 3.20 3.20 3.40
** ** ** ** ** ** 0.40 ** ** ** ** ** ** ** 0.40 ** ** ** ** ** **
NO YES NO NO YES NO YES NO NO YES YES NO NO YES YES NO NO YES NO NO YES
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 - 0.30 0.40 0.50 16 20 28 32 N 40 ND 4 5 7 8 10 4 5 7 8 10 NE WHHB WHHC WHHD-1 WHHD-2 ----JEDEC L1
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 0.25 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 T2855-1, 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.
3.30 3.40 3.20
** SEE COMMON DIMENSIONS TABLE
PACKAGE OUTLINE, 16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm
-DRAWING NOT TO SCALE-
21-0140
H
2
2
The MAX9702 thin QFN-EP package features an exposed thermal pad on its underside. This pad lowers the package's thermal impedance by providing a direct-heat conduction path from the die to the printed circuit board. The exposed pad is internally connected to VSS. Connect the exposed thermal pad to an isolated plane.
______________________________________________________________________________________
31
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier MAX9702
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.)
TSSOP4.40mm.EPS
PACKAGE OUTLINE, TSSOP 4.40mm BODY
21-0066
G
1
1
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.
32 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

▲Up To Search▲

Price & Availability of MAX9702EUI

	To Download MAX9702EUI Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .