19-3160; Rev 1; 3/04 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers Features The MAX9703/MAX9704 mono/stereo class D audio power amplifiers provide class AB amplifier performance with class D efficiency, conserving board space and eliminating the need for a bulky heatsink. Using a class D architecture, these devices deliver up to 15W while offering up to 78% efficiency. Proprietary and patent-protected modulation and switching schemes render the traditional class D output filter unnecessary. The MAX9703/MAX9704 offer two modulation schemes: a fixed-frequency mode (FFM), and a spread-spectrum mode (SSM) that reduces EMI-radiated emissions due to the modulation frequency. The device utilizes a fully differential architecture, a full bridged output, and comprehensive click-and-pop suppression. The MAX9703/MAX9704 feature high 80dB PSRR, low 0.07% THD+N, and SNR in excess of 100dB. Short-circuit and thermal-overload protection prevent the devices from being damaged during a fault condition. The MAX9703 is available in a 32-pin TQFN (5mm x 5mm x 0.8mm) package. The MAX9704 is available in a 32-pin TQFN (7mm x 7mm x 0.8mm) package. Both devices are specified over the extended -40°C to +85°C temperature range. ♦ Filterless Class D Amplifier ♦ Unique Spread-Spectrum Mode Offers 5dB Emissions Improvement Over Conventional Methods ♦ Up to 78% Efficient ♦ 15W Output Power into 8Ω ♦ Up to 20W Peak Power ♦ Low 0.07% THD+N ♦ High PSRR (80dB at 1kHz) ♦ 10V to 25V Single-Supply Operation ♦ Differential Inputs Minimize Common-Mode Noise ♦ Pin-Selectable Gain Reduces Component Count ♦ Industry-Leading Click-and-Pop Suppression ♦ Low Quiescent Current (24mA) ♦ Low-Power Shutdown Mode (0.2µA) ♦ Short-Circuit and Thermal-Overload Protection ♦ Available in Thermally Efficient, Space-Saving Packages 32-Pin TQFN (5mm x 5mm x 0.8mm)–MAX9703 32-Pin TQFN (7mm x 7mm x 0.8mm)–MAX9704 Applications Ordering Information LCD TVs LCD Monitors Hands-Free Car Phone Adaptors Desktop PCs Automotive LCD Projectors PART TEMP RANGE o o PIN-PACKAGE MAX9703ETJ -40 C to +85 C 32 TQFN-EP* MAX9704ETJ -40oC to +85oC 32 TQFN-EP* AMP Mono Stereo *EP = Exposed paddle. Block Diagrams 0.47µF IN+ OUTL+ H-BRIDGE 0.47µF MAX9703 0.47µF MAX9704 INL+ INL- OUTL- INR+ OUTR+ OUT+ H-BRIDGE 0.47µF IN- OUT- 0.47µF H-BRIDGE 0.47µF INR- OUTR- Pin Configurations appear at end of data sheet. ________________________________________________________________ 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. 1 MAX9703/MAX9704 General Description MAX9703/MAX9704 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND.) VDD to PGND, AGND .............................................................30V OUTR_, OUTL_, C1N..................................-0.3V to (VDD + 0.3V) C1P............................................(VDD - 0.3V) to (CHOLD + 0.3V) CHOLD ........................................................(VDD - 0.3V) to +40V All Other Pins to GND.............................................-0.3V to +12V Duration of OUTR_/OUTL_ Short Circuit to GND, VDD ..................................................10s Continuous Input Current (VDD, PGND) ...............................1.6A Continuous Input Current......................................................0.8A Continuous Input Current (all other pins)..........................±20mA Continuous Power Dissipation (TA = +70°C) MAX9703 32-Pin TQFN (derate 21.3mW/°C above +70°C)..........................................................1702.1mW MAX9704 32-Pin TQFN (derate 33.3mW/°C above +70°C)..........................................................2666.7mW Junction Temperature ......................................................+150°C Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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 = 15V, GND = PGND = 0V, SHDN ≥ VIH, AV = 16dB, CSS = CIN = CREG = 0.47µF, C1 = 100nF, C2 = 1µF, FS1 = FS2 = GND (fS = 660kHz), RL connected between OUTL+ and OUTL- and OUTR+ and OUTR-, T A = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 25 V GENERAL Supply Voltage Range VDD Inferred from PSRR test Quiescent Current IDD RL = OPEN Shutdown Current ISHDN Turn-On Time tON Amplifier Output Resistance in Shutdown Input Impedance RIN 10 MAX9703 14 22 MAX9704 24 34 0.2 1.5 CSS = 470nF 100 CSS = 180nF 50 Voltage Gain AV Gain Matching 150 330 AV = 13dB 35 58 80 AV = 16dB 30 48 65 AV = 19.1dB 23 39 55 Output Offset Voltage Common-Mode Rejection Ratio Power-Supply Rejection Ratio (Note 3) Output Power 2 10 15 22 29.4 29.6 29.8 G1 = L, G2 = H 18.9 19.1 19.3 G1 = H, G2 = L 12.8 13 13.2 G1 = H, G2 = H 15.9 16 16.3 0.5 ±6 VOS CMRR fIN = 1kHz, input referred VDD = 10V to 25V PSRR POUT kΩ G1 = L, G2 = L Between channels (MAX9704) 200mVP-P ripple THD+N = 10%, f = 1kHz, TA = +25°C 60 54 µA ms SHDN = GND AV = 29.6dB mA kΩ dB % ±30 mV dB 80 fRIPPLE = 1kHz 80 fRIPPLE = 20kHz 66 RL = 4Ω 7.5 RL = 8Ω, VDD = 20V 20 dB W _______________________________________________________________________________________ 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers (VDD = 15V, GND = PGND = 0V, SHDN ≥ VIH, AV = 16dB, CSS = CIN = CREG = 0.47µF, C1 = 100nF, C2 = 1µF, FS1 = FS2 = GND (fS = 660kHz), RL connected between OUTL+ and OUTL- and OUTR+ and OUTR-, T A = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) PARAMETER Total Harmonic Distortion Plus Noise Signal-to-Noise Ratio SYMBOL THD+N SNR CONDITIONS RL = 8Ω, POUT = 10W, f = 1kHz BW = 22Hz to 22kHz A-weighted Crosstalk MIN fIN = 1kHz, either FFM or SSM, RL = 8Ω, POUT = 4W FFM fOSC η Efficiency Regulator Output UNITS % 94 SSM 88 FFM 97 SSM FS1 = L, FS2 = L MAX 0.07 dB 91 Left to right, right to left, 8Ω load, fIN = 10kHz Oscillator Frequency TYP 65 560 670 FS1 = L, FS2 = H 940 FS1 = H, FS2 = L 470 FS1 = H, FS2 = H (spread-spectrum mode) 670 ±7% POUT = 15W, f = 1kHz, RL = 8Ω VREG dB 800 kHz 78 % 6 V DIGITAL INPUTS (SHDN, FS_, G_) (Note 4) VIH Input Thresholds VIL Input Leakage Current 2.5 0.8 ±1 V µA Note 1: All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design. Note 2: Testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For RL = 8Ω, L = 68µH. For RL = 4Ω, L = 33µH. Note 3: PSRR is specified with the amplifier inputs connected to GND through CIN. Note 4: Do not apply more than 8V to any logic pin. _______________________________________________________________________________________ 3 MAX9703/MAX9704 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (33µH with 4Ω, 68µH with 8Ω, part in SSM mode, 136µH with 16Ω, measurement BW = 22Hz to 22kHz, unless otherwise noted.) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY VDD = 15V RL = 4Ω AV = 16dB VDD = 15V RL = 8Ω AV = 16dB 10 1 THD+N (%) POUT = 4W POUT = 8W 0.1 0.1 POUT = 500mW POUT = 500mW 0.01 0.01 1k 10k 0.01 10 100k 100 1k 10k 100k 10 100 1k 10k 100k FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER VDD = 15V RL = 4Ω AV = 16dB 10 10 MAX9703/04 toc06 VDD = 20V RL = 8Ω AV = 16dB POUT = 8W MAX9703/04 toc05 100 MAX9703/04 toc04 10 100 POUT = 8W 0.1 POUT = 500mW 10 VDD = 20V RL = 8Ω AV = 16dB 1 THD+N (%) THD+N (%) 1 MAX9703/04 toc03 10 MAX9703/04 toc01 10 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY MAX9703/04 toc02 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY VDD = 15V RL = 8Ω AV = 16dB f = 10kHz THD+N (%) THD+N (%) SSM THD+N (%) 1 1 f = 10kHz 1 f = 1kHz 0.1 0.1 0.1 f = 1kHz FFM f = 100Hz f = 100Hz 0.01 0.01 10 100 1k 10k 1 2 3 4 5 6 7 8 9 OUTPUT POWER (W) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER f = 10kHz MAX9703/04 toc07 VDD = 20V RL = 8Ω AV = 16dB 10 OUTPUT POWER (W) EFFICIENCY vs. OUTPUT POWER VDD = 20V RL = 8Ω AV = 16dB f = 1kHz f = 1kHz SSM 0.1 FFM (335kHz) f = 100Hz 6 8 10 12 14 16 18 OUTPUT POWER (W) 4 70 60 50 RL = 4Ω 40 20 VDD = 12V AV = 16dB f = 1kHz 0 0.01 4 80 10 0.01 2 RL = 8Ω 90 30 0.1 0 100 EFFICIENCY (%) THD+N (%) 1 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 10 MAX9703/04 toc08 FREQUENCY (Hz) 100 10 0 100k MAX9703/04 toc09 0.01 THD+N (%) MAX9703/MAX9704 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers 20 0 1 2 3 4 5 6 7 8 9 10111213141516171819 20 OUTPUT POWER (W) 0 1 2 3 4 5 6 7 OUTPUT POWER (W) _______________________________________________________________________________________ 8 9 10 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers 50 40 30 VDD = 15V AV = 16dB f = 1kHz 10 12 RL = 16Ω 10 8 6 AV = 16dB THD+N = 10% 2 8 10 16 18 12 14 20 OUTPUT POWER (W) 16 19 SUPPLY VOLTAGE (V) OUTPUT POWER vs. LOAD RESISTANCE COMMON-MODE REJECTION RATIO vs. FREQUENCY 0 -40 100 -20 MAX9703/04 toc12 -60 -80 -100 -120 10 100 1k 10k 100 -80 RIGHT TO LEFT -100 -40 MAX9703/04 toc17 -20 -60 -80 -100 SSM MODE AV = 16dB UNWEIGHTED fIN = 1kHz POUT = 5W RL = 8Ω 0 -20 -40 -60 -80 -100 -140 -140 100k 100k -120 -120 -120 10k OUTPUT FREQUENCY SPECTRUM 20 OUTPUT MAGNITUDE (dB) -60 FFM MODE AV = 16dB UNWEIGHTED fIN = 1kHz POUT = 5W RL = 8Ω 0 OUTPUT MAGNITUDE (dB) LEFT TO RIGHT 20 1k FREQUENCY (Hz) OUTPUT FREQUENCY SPECTRUM -40 10k 10 100k FREQUENCY (Hz) MAX9703/04 toc16 AV = 16dB 1% THD+N VDD = 15V 8Ω LOAD FREQUENCY (Hz) AV = 16dB RL = 8Ω 200mVP-P INPUT VDD = 15V -40 CROSSTALK vs. FREQUENCY CROSSTALK (dB) 0 -80 10 1k 100 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY -70 100 10 -60 THD+N = 1% 10 THD+N = 1% LOAD RESISTANCE (Ω) -30 LOAD RESISTANCE (Ω) -20 6 1 -50 1 8 25 -20 0 0 22 VDD = 15V RL = 8Ω AV = 16dB -10 CMRR (dB) THD+N = 10% 13 PSRR (dB) VDD = 20V RL = 8Ω AV = 16dB 10 0 10 MAX9703/04 toc14 6 4 MAX9703/04 toc13 24 22 20 18 16 14 12 10 8 6 4 2 2 12 2 0 0 THD+N = 10% 14 4 4 0 OUTPUT POWER (W) RL = 8Ω 16 MAX9703/04 toc18 20 14 VDD = 15V RL = 8Ω AV = 16dB 18 MAX9703/04 toc15 RL = 8Ω 60 16 OUTPUT POWER (W) EFFICIENCY (%) 70 18 OUTPUT POWER (W) 80 20 MAX9703/04 toc11 RL = 16Ω 90 20 MAX9703/04 toc10 100 OUTPUT POWER vs. LOAD RESISTANCE OUTPUT POWER vs. SUPPLY VOLTAGE EFFICIENCY vs. OUTPUT POWER 0 2 4 6 8 10 12 14 16 18 20 FREQUENCY (kHz) 0 2 4 6 8 10 12 14 16 18 20 FREQUENCY (kHz) _______________________________________________________________________________________ 5 MAX9703/MAX9704 Typical Operating Characteristics (continued) (33µH with 4Ω, 68µH with 8Ω, part in SSM mode, 136µH with 16Ω, measurement BW = 22Hz to 22kHz, unless otherwise noted.) Typical Operating Characteristics (continued) (33µH with 4Ω, 68µH with 8Ω, part in SSM mode, 136µH with 16Ω, measurement BW = 22Hz to 22kHz, unless otherwise noted.) -60 -80 -100 -40 -60 -80 -140 0 2 4 100k TURN-ON/TURN-OFF RESPONSE MAX9703/04 toc22 1M 10M OUTPUT SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE 20 15 10 0.30 0.25 0.20 0.15 0.10 0.05 0 10 13 16 19 SUPPLY VOLTAGE (V) 6 0.35 MAX9703/04 toc23 25 0 20ms/div 100M SUPPLY CURRENT vs. SUPPLY VOLTAGE 5 f = 1kHz RL = 8Ω 10M FREQUENCY (Hz) SUPPLY CURRENT (µA) 1V/div SUPPLY CURRENT (mA) 5V/div 1M FREQUENCY (Hz) 30 SHDN -80 100k 100M 35 CSS = 180pF -60 -120 -120 6 8 10 12 14 16 18 20 FREQUENCY (kHz) -40 -100 -100 -120 RBW = 10kHz VDD = 15V -20 MAX9703/04 toc21 MAX9703/04 toc20 -20 0 MAX97703/04 toc24 -40 RBW = 10kHz VDD = 15V OUTPUT AMPLITUDE (dBV) -20 0 OUTPUT AMPLITUDE (dBV) SSM MODE AV = 16dB A-WEIGHTED fIN = 1kHz POUT = 5W RL = 8Ω 0 MAX9703/04 toc19 20 WIDEBAND OUTPUT SPECTRUM (SSM MODE) WIDEBAND OUTPUT SPECTRUM (FFM MODE) OUTPUT FREQUENCY SPECTRUM OUTPUT MAGNITUDE (dB) MAX9703/MAX9704 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers 22 25 10 12 14 16 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 18 20 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers PIN NAME FUNCTION MAX9703 MAX9704 1, 2, 23, 24 1, 2, 23, 24 PGND 3, 4, 21, 22 3, 4, 21, 22 VDD Power-Supply Input 5 5 C1N Charge-Pump Flying Capacitor Negative Terminal 6 6 C1P Charge-Pump Flying Capacitor Positive Terminal 7 7 CHOLD 8, 17, 20, 25, 26, 31, 32 8 N.C. No Connection. Not internally connected. 9 14 REG Internal Regulator Output. Bypass with a 0.47µF capacitor to PGND. 10 13 AGND Analog Ground 11 — IN- Negative Input 12 — IN+ Positive Input 13 12 SS Soft-Start. Connect a 0.47µF capacitor from SS to GND to enable soft-start feature. 14 11 SHDN 15 17 G1 Gain-Select Input 1 16 18 G2 Gain-Select Input 2 18 19 FS1 Frequency-Select Input 1 19 20 FS2 Frequency-Select Input 2 27, 28 — OUT- Negative Audio Output 29, 30 — OUT+ Positive Audio Output — 9 INL- Left-Channel Negative Input — 10 INL+ Left-Channel Positive Input — 15 INR- Right-Channel Negative Input — 16 INR+ Right-Channel Positive Input — 25, 26 OUTR- Right-Channel Negative Audio Output — 27, 28 OUTR+ Right-Channel Positive Audio Output — 29, 30 OUTL- Left-Channel Negative Audio Output — 31, 32 OUTL+ Left-Channel Positive Audio Output — — EP Exposed Paddle. Connect to GND. Power Ground Charge-Pump Hold Capacitor. Connect a 1µF capacitor from CHOLD to VDD. Active-Low Shutdown. Connect SHDN to GND to disable the device. Connect to VDD for normal operation. _______________________________________________________________________________________ 7 MAX9703/MAX9704 Pin Description MAX9703/MAX9704 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers Detailed Description The MAX9703/MAX9704 filterless, class D audio power amplifiers feature several improvements to switchmode amplifier technology. The MAX9703 is a mono amplifier, the MAX9704 is a stereo amplifier. These devices offer class AB performance with class D efficiency, while occupying minimal board space. A unique filterless modulation scheme and spread-spectrum switching mode create a compact, flexible, lownoise, efficient audio power amplifier. The differential input architecture reduces common-mode noise pickup, and can be used without input-coupling capacitors. The devices can also be configured as a single-ended input amplifier. Comparators monitor the device inputs and compare the complementary input voltages to the triangle waveform. The comparators trip when the input magnitude of the triangle exceeds their corresponding input voltage. Operating Modes VIN = 0V OUT- OUT+ Figure 1. MAX9704 Outputs with No Input Signal Applied Fixed-Frequency Modulation (FFM) Mode The MAX9703/MAX9704 feature three FFM modes with different switching frequencies (Table 1). In FFM mode, the frequency spectrum of the class D output consists of the fundamental switching frequency and its associated harmonics (see the Wideband FFT graph in the Typical Operating Characteristics). The MAX9703/ MAX9704 allow the switching frequency to be changed by ±35%, should the frequency of one or more of the harmonics fall in a sensitive band. This can be done at any time and does not affect audio reproduction. Table 1. Operating Modes Spread-Spectrum Modulation (SSM) Mode The MAX9703/MAX9704 feature a unique, patented spread-spectrum 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 FS1 = FS2 = H. In SSM mode, the switching frequency varies randomly by ±7% around the center frequency (670kHz). The modulation scheme remains the same, but the period of the triangle waveform changes from cycle to cycle. 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. Efficiency of a class D amplifier is attributed to the region of operation of the output stage transistors. In a class D amplifier, the output transistors act as currentsteering switches and consume negligible additional power. Any power loss associated with the class D output stage is mostly due to the I*R loss of the MOSFET on-resistance, 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 MAX9704 still exhibits >78% efficiency under the same conditions (Figure 2). 8 FS1 FS2 SWITCHING MODE (kHz) L L 670 L H 940 H L 470 H H 670 ±7% Efficiency _______________________________________________________________________________________ 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers 90 MAX9704 80 EFFICIENCY (%) 70 60 50 CLASS AB 40 30 20 VDD = 15V f = 1kHz RL = 8Ω 10 0 0 2 4 6 8 10 12 14 16 18 20 OUTPUT POWER (W) Figure 2. MAX9704 Efficiency vs. Class AB Efficiency Shutdown The MAX9703/MAX9704 have a shutdown mode that reduces power consumption and extends battery life. Driving SHDN low places the device in low-power (0.2µA) shutdown mode. Connect SHDN to a logic high for normal operation. Click-and-Pop Suppression The MAX9703/MAX9704 feature comprehensive clickand-pop suppression that eliminates audible transients on startup and shutdown. While in shutdown, the Hbridge is pulled to GND through 330kΩ. 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. Following startup, a soft-start function gradually unmutes the input amplifiers. The value of the soft-start capacitor has an impact on the click/pop levels. For optimum performance, CSS should be at least 180nF with a voltage rating of at least 7V. The MAX9703/MAX9704 do not require an output filter. The devices rely 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. Eliminating the output filter results in a smaller, less-costly, more-efficient solution. Because the frequency of the MAX9703/MAX9704 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 can be damaged. For optimum results, use a speaker with a series inductance > 30µH. Typical 8Ω speakers exhibit series inductances in the range of 30µH to 100µH. Optimum efficiency is achieved with speaker inductances > 60µH. Gain Selection Table 2 shows the suggested gain settings to attain a maximum output power from a given peak input voltage and given load. 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 example, an 8mVDC offset across an 8Ω load results in 1mA extra current consumption in a class AB device. In the class D case, an 8mV offset into 8Ω equates to an additional power drain of 8µW. Due to the high efficiency of the class D amplifier, this represents an additional quiescent current draw of: 8µW/(VDD/100 ✕ η), which is in the order of a few microamps. Table 2. Gain Settings GAIN (dB) INPUT DIFF (VRMS) RL (Ω) POUT AT 10% THD+N (W) Filterless Operation 13.0 0.67 4 9 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 16.0 0.48 4 9 19.1 0.33 4 9 29.6 0.10 4 9 13.0 1.23 8 15 16.0 0.86 8 15 19.1 0.61 8 15 29.6 0.19 8 15 Applications Information _______________________________________________________________________________________ 9 MAX9703/MAX9704 EFFICIENCY vs. OUTPUT POWER 100 swings (2 ✕ VDD peak-to-peak) and causes large ripple currents. Any parasitic resistance in the filter components results in a loss of power, lowering the efficiency. MAX9703/MAX9704 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers Input Amplifier Differential Input The MAX9703/MAX9704 feature a differential input structure, making them compatible with many CODECs, and offering improved noise immunity over a single-ended input amplifier. In devices such as PCs, noisy digital signals can be picked up by the amplifier’s input traces. The signals appear at the amplifiers’ inputs as commonmode noise. A differential input amplifier amplifies the difference of the two inputs, any signal common to both inputs is canceled. Single-Ended Input The MAX9703/MAX9704 can be configured as singleended input amplifiers by capacitively coupling either input to GND and driving the other input (Figure 3). Component Selection Input Filter An input capacitor, CIN, in conjunction with the input impedance of the MAX9703/MAX9704, forms a highpass filter that removes the DC bias from an incoming signal. The AC-coupling capacitor allows the amplifier 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 2πRINCIN Choose CIN so f-3dB is well below the lowest frequency of interest. Setting f-3dB too high affects the low-frequency response of the amplifier. Use capacitors with dielectrics that have low-voltage coefficients, such as tantalum or aluminum electrolytic. Capacitors with highvoltage coefficients, such as ceramics, may result in increased distortion at low frequencies. Charge-Pump Capacitor Selection Use capacitors with an ESR less than 100mΩ 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. Flying Capacitor (C1) The value of the flying capacitor (C1) affects the load regulation and output resistance of the charge pump. A C1 value that is too small degrades the device’s ability to provide sufficient current drive. Increasing the value of 10 0.47µF SINGLE-ENDED AUDIO INPUT IN+ MAX9703/ IN- MAX9704 0.47µF Figure 3. Single-Ended Input C1 improves load regulation and reduces the chargepump output resistance to an extent. Above 1µF, the onresistance of the switches and the ESR of C1 and C2 dominate. Hold Capacitor (C2) The output capacitor value and ESR directly affect the ripple at CHOLD. Increasing 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. Output Filter The MAX9703/MAX9704 do not require an output filter and can pass FCC emissions standards with 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 EMIsensitive 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 connect the amplifier to the speaker. Refer to the MAX9704 Evaluation Kit schematic for details of this filter. Sharing Input Sources In certain systems, a single audio source can be shared by multiple devices (speaker and headphone amplifiers). When sharing inputs, it is common to mute the unused device, rather than completely shutting it down, preventing the unused device inputs from distorting the input signal. Mute the MAX9703/MAX9704 by driving SS low through an open-drain output or MOSFET (see the System Diagram). Driving SS low turns off the class D output stage, but does not affect the input bias levels of the MAX9703/MAX9704. Be aware that during normal operation, the voltage at SS can be up to 7V, depending on the MAX9703/MAX9704 supply. ______________________________________________________________________________________ 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers ply connection to VDD is assumed. Additional bulk capacitance should be added as required depending on the application and power-supply characteristics. AGND and PGND should be star connected to system ground. Refer to the MAX9704 Evaluation Kit for layout guidance. 25 OUTR- 26 OUTR- 27 OUTR+ 28 OUTR+ 29 OUTL- 30 OUTL- 31 OUTL+ 32 OUTL+ 25 N.C. 26 N.C. 27 OUT- 28 OUT- 29 OUT+ 30 OUT+ 32 N.C. TOP VIEW 31 N.C. Pin Configurations PGND 1 24 PGND PGND 1 24 PGND PGND 2 23 PGND PGND 2 23 PGND VDD 3 22 VDD VDD 3 22 VDD VDD 4 21 VDD VDD 4 21 VDD 20 FS2 C1N 5 MAX9703 20 N.C. C1N 5 MAX9704 15 16 INR- 14 INR+ 13 REG 12 SS AGND 11 SHDN 9 TQFN (5mm x 5mm) 10 REG INL- G1 INL+ 17 15 8 16 N.C. G2 N.C. G1 17 14 8 SHDN N.C. 13 G2 12 FS1 18 SS 19 7 IN+ 6 CHOLD 11 C1P FS1 IN- FS2 18 10 19 7 AGND 6 9 C1P CHOLD TQFN (7mm x 7mm) Chip Information MAX9703 TRANSISTOR COUNT: 3093 MAX9704 TRANSISTOR COUNT: 4630 PROCESS: BiCMOS ______________________________________________________________________________________ 11 MAX9703/MAX9704 Supply Bypassing/Layout Proper power-supply bypassing ensures low distortion operation. For optimum performance, bypass VDD to PGND with a 0.1µF capacitor as close to each VDD pin as possible. A low-impedance, high-current power-sup- 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers MAX9703/MAX9704 Functional Diagrams 10V TO 25V 100µF 25V 0.1µF 25V 1 2 PGND 0.47µF 0.47µF 0.1µF 25V 3 4 21 22 VDD VDD 23 24 PGND 11 IN+ OUT+ 30 MODULATOR 12 IN- OUT+ 29 OUT- 28 H-BRIDGE OUT- 27 VREG VREG VIH VREG VREG 18 FS1 19 FS2 14 SHDN 15 G1 16 G2 13 SS 0.18µF 10V VREG 0.47µF 10V 9 REG OSCILLATOR GAIN CONTROL SHUTDOWN CONTROL MAX9703 C1P 6 CHARGE PUMP 5 C1 0.1µF 25V C1N 10 AGND CHOLD 7 C2 1µF 25V LOGIC INPUTS SHOWN FOR AV = 16dB (SSM). VIN = LOGIC HIGH > 2.5V. 12 VDD ______________________________________________________________________________________ 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers 10V TO 25V 100µF 25V 0.1µF 25V 1 2 PGND 0.47µF 0.47µF 0.1µF 25V 3 4 21 22 VDD VDD 23 24 PGND 10 INL+ OUTL+ 32 MODULATOR 9 INL- OUTL+ 31 OUTL- 30 H-BRIDGE OUTL- 29 VREG VREG 0.47µF 0.47µF 19 FS1 20 FS2 OSCILLATOR 15 INR+ OUTR+ 26 MODULATOR 16 INR- OUTR+ 25 OUTR- 28 H-BRIDGE OUTR- 27 VIH VREG VREG 11 SHDN 17 G1 18 G2 12 SS 0.18µF 10V VREG 0.47µF 10V 14 REG MAX9704 GAIN CONTROL SHUTDOWN CONTROL C1P 6 CHARGE PUMP 5 C1 0.1µF 25V C1N 13 AGND CHOLD 7 VDD C2 1µF 25V LOGIC INPUTS SHOWN FOR AV = 16dB (SSM). VIN = LOGIC HIGH > 2.5V. ______________________________________________________________________________________ 13 MAX9703/MAX9704 Functional Diagrams (continued) 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers MAX9703/MAX9704 System Diagram VDD 100µF 1µF 0.47µF VDD SHDN INL- OUTL- INL+ OUTL+ 0.47µF CODEC MAX9704 0.47µF INR+ OUTR+ INR- OUTR- 0.47µF 5V SS 100kΩ 0.18µF SHDN 1µF VDD INL1µF 1µF 15kΩ MAX9722B INL+ OUTL INR+ OUTR INR- PVSS SVSS 15kΩ 1µF 30kΩ 30kΩ C1P CIN 1µF 1µF LOGIC INPUTS SHOWN FOR AV = 16dB (SSM). 14 ______________________________________________________________________________________ 1µF 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers 32, 44, 48L QFN.EPS D2 D CL D/2 b D2/2 k E/2 E2/2 CL (NE-1) X e E E2 k L DETAIL A e (ND-1) X e DETAIL B e CL L L1 CL L L e A1 A2 e DALLAS SEMICONDUCTOR A PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE 32, 44, 48, 56L THIN QFN, 7x7x0.8mm APPROVAL DOCUMENT CONTROL NO. 21-0144 REV. D 1 ______________________________________________________________________________________ 2 15 MAX9703/MAX9704 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.) MAX9703/MAX9704 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers 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.) DALLAS SEMICONDUCTOR PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE 32, 44, 48, 56L THIN QFN, 7x7x0.8mm APPROVAL DOCUMENT CONTROL NO. 21-0144 16 ______________________________________________________________________________________ REV. D 2 2 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers b CL 0.10 M C A B D2/2 D/2 PIN # 1 I.D. QFN THIN.EPS D2 0.15 C A D k 0.15 C B PIN # 1 I.D. 0.35x45∞ E/2 E2/2 CL (NE-1) X e E E2 k L DETAIL A e (ND-1) X e DETAIL B e L1 L CL CL L L e e 0.10 C A C A1 0.08 C A3 PACKAGE OUTLINE 16, 20, 28, 32, 40L, THIN QFN, 5x5x0.8mm 21-0140 E 1 ______________________________________________________________________________________ 2 17 MAX9703/MAX9704 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.) MAX9703/MAX9704 15W, Filterless, Spread-Spectrum Mono/Stereo Class D Amplifiers Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) COMMON DIMENSIONS EXPOSED PAD VARIATIONS PKG. 20L 5x5 28L 5x5 32L 5x5 40L 5x5 16L 5x5 SYMBOL MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. A A1 A3 b D E L1 0 0.02 0.05 0 0.20 REF. 0.20 REF. 0.02 0.05 0.02 0.05 0 0.20 REF. 0.20 REF. 0 - 0.05 0.20 REF. 0.25 0.30 0.35 0.25 0.30 0.35 0.20 0.25 0.30 0.20 0.25 0.30 0.15 0.20 0.25 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 e k L 0.02 0.05 0.65 BSC. 0.80 BSC. 0.50 BSC. 0.50 BSC. 0.40 BSC. - 0.25 - 0.25 - 0.25 0.35 0.45 0.25 - 0.25 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 - - - - - N ND NE 16 4 4 20 5 5 JEDEC WHHB WHHC - - - - - - WHHD-1 - 0.30 0.40 0.50 32 8 8 40 10 10 WHHD-2 - 28 7 7 E2 DOWN BONDS MIN. NOM. MAX. T1655-1 T1655-2 3.00 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.10 3.20 T2055-2 T2055-3 3.00 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.10 3.20 T2055-4 T2855-1 T2855-2 T2855-3 T2855-4 T2855-5 T2855-6 T2855-7 T3255-2 T3255-3 T3255-4 3.00 3.15 2.60 3.15 2.60 2.60 3.15 2.60 3.00 3.00 3.00 3.10 3.25 2.70 3.25 2.70 2.70 3.25 2.70 3.10 3.10 3.10 3.10 3.25 2.70 3.25 2.70 2.70 3.25 2.70 3.10 3.10 3.10 T4055-1 3.20 3.30 3.40 3.20 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 D2 PKG. CODES 3.20 3.35 2.80 3.35 2.80 2.80 3.35 2.80 3.20 3.20 3.20 MIN. 3.00 3.15 2.60 3.15 2.60 2.60 3.15 2.60 3.00 3.00 3.00 NOM. MAX. ALLOWED 3.20 3.35 2.80 3.35 2.80 2.80 3.35 2.80 3.20 3.20 3.20 3.30 3.40 NO YES NO YES NO NO NO YES YES NO NO YES NO YES NO YES 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. PACKAGE OUTLINE 16, 20, 28, 32, 40L, THIN QFN, 5x5x0.8mm 21-0140 E 2 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.