MAX98308

19-5848; Rev 2; 9/11 EVALUATION KIT AVAILABLE MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier General Description The MAX98307/MAX98308 fully differential mono Class DG multilevel power amplifiers with integrated inverting charge pumps offer highly efficient, high-power audio solutions for portable applications. Class DG multilevel modulation extends the dynamic range of the output signal by employing a charge-pumpgenerated negative rail as needed to extend the supply range. This scheme results in high efficiency over a wide output power range. The ICs combine Maxim’s active emissions limiting edge rate and overshoot control circuitry with multilevel output modulation to greatly reduce EMI. These features eliminate the need for output filtering as compared to traditional Class D devices, reducing component count and cost. The MAX98307’s 16-pin TQFN package features an adjustable gain set by external resistors. The MAX98308’s space-saving 12-bump WLP package features an internally fixed gain of 8.5dB, 11.5dB, 14.5dB, 17.5dB, and 20.5dB set by a single gain input. Both devices operate over the extended -40NC to +85NC temperature range. Benefits and Features S High Efficiency Combined with High Output Power  Class DG Multilevel Modulation Ensures Maximum Efficiency Over Wide Output Power Range S Improves Battery Life  Low 1.85mA Quiescent Current S High Output Power at 1% THD+N  1.54W at VPVDD = 3.6V, 8I + 68µH Load  2.85W at VPVDD = 5V, 8I + 68µH Load S High Output Power at 10% THD+N  1.77W at VPVDD = 3.6V, 8I + 68µH Load  3.3W at VPVDD = 5V, 8I + 68µH Load S 84% Efficiency (VPVDD = 3.6V, at 500mW Output) S Active Emissions Limiting and Class DG Multilevel Output Modulation Eliminates EMI Output Filtering Requirement S Integrated Charge Pump and High Efficiency Results in Small Solution Size S Excellent RF Immunity S Click-and-Pop Suppression S Thermal and Overcurrent Protection S Low-Current Shutdown Mode Ordering Information appears at end of data sheet. For related parts and recommended products to use with this part, refer to www.maxim-ic.com/MAX98307.related. Applications Cellular Phones Smartphones Notebook Computers VoIP Phones Portable Audio Tablet PCs Simplified Block Diagrams SHDN FB+ CHARGE PUMP VCC PVDD PVSS SVSS C1P C1N SHDN GAIN PVDD PVSS C1P MAX98307 IN+ INCLASS DG AMPLIFIER OUT+ IN+ OUTIN- MAX98308 CHARGE PUMP C1N OUT+ CLASS DG AMPLIFIER OUT- FBGND PGND GND PGND ����������������������������������������������������������������� Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier MAX98307 Typical Application Circuit 2.6V TO 5.25 0.1µF 10µF* 0.1µF 10µF SHDN 1 FB+ 12 20kI 0.33µF 10kI 0.33µF 10kI IN+ 11 IN- 10 VCC 13 3 PVDD 7 SVSS PVSS 14 16 C1P 15 C1N 4 OUT+ 4.7µF CHARGE PUMP MAX98307 CLASS DG AMPLIFIER 5 OUT- 20kI FB- 9 2 GND *SYSTEM BULK CAPACITOR 6 PGND 8 N.C. MAX98308 Typical Application Circuit 2.6V TO 5.25 10µF* 0.1µF 10µF SHDN B2 PVDD A3 C1 PVSS A1 C1P MAX98308 GAIN B3 0.33µF 0.33µF CHARGE PUMP B1 C1N A4 OUT+ 4.7µF IN+ C2 IN- C3 CLASS DG AMPLIFIER B4 OUT- A2 GND *SYSTEM BULK CAPACITOR C4 PGND ����������������������������������������������������������������� Maxim Integrated Products 2 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier ABSOLUTE MAXIMUM RATINGS PVDD to GND .......................................................... -0.3V to +6V PGND to GND ..................................................... -0.3V to +0.3V C1N to GND .......................................... (VPVSS - 0.3V) to +0.3V IN+, IN- (MAX98307)................................ -0.3V to (VCC + 0.3V) VCC to PVDD (MAX98307) .................................. -0.3V to +0.3V PVSS to SVSS (MAX97307) .................................. -0.3V to +0.3V PVSS, SVSS to GND (MAX98307)........................... -6V to +0.3V IN+, IN- (MAX98308)............................................... -0.3V to +6V PVSS to GND (MAX98308) ..................................... -6V to +0.3V All Other Pins to GND ...........................-0.3V to (VPVDD + 0.3V) Continuous Current Into/Out of PVDD, VCC, PGND, GND, OUT+, OUT-, C1P, C1N, PVSS, SVSS ...................... Q800mA Continuous Current (all other pins) ................................. Q20mA Duration of OUT+/OUT- Short Circuit to PGND or PVDD ................................................................. Continuous Short-Circuit Duration Between OUT+ and OUT- Pins ............................................ Continuous Continuous Power Dissipation (TA = +70NC) for Multilayer Board TQFN (derate 20.8mW/NC above +70NC).................. 1667mW WLP (derate 13.7mW/NC above +70NC).................... 1100mW Junction Temperature .....................................................+150NC Operating Temperature Range .......................... -40NC to +85NC Storage Temperature Range............................ -65NC to +150NC Lead Temperature (soldering, 10s) (TQFN-EP) ............ +300NC Soldering Temperature (reflow) (WLP) ......................... +260NC 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. PACKAGE THERMAL CHARACTERISTICS (Note 1) TQFN Junction-to-Ambient Thermal Resistance (BJA) .......... 48NC/W Junction-to-Case Thermal Resistance (BJC) ............... 10NC/W WLP Junction-to-Ambient Thermal Resistance (BJA) .......... 73NC/W Junction-to-Case Thermal Resistance (BJC) ............... 30NC/W Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8I + 68FH between OUT+ and OUT-, (MAX98307 RIN+ = RIN- = 10kI, RFB+ = RFB- = 20kI), CIN+ = CIN- = 0.33FF, AV = 14.5dB, AC measurement bandwidth 20Hz to 20kHz, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25NC.) (Notes 2, 3) PARAMETER Power-Supply Range Quiescent Current Shutdown Current Power-Supply Rejection Ratio (Note 4) SYMBOL VPVDD, VCC IDD ISHDN PSRR VPVDD = 3.6V SHDN = GND VPVDD = 2.6V to 5.25V f = 217Hz, 200mVP-P ripple f = 10kHz, 200mVP-P ripple tON VBIAS RIN AV = 20.5dB (maximum gain) 15 Time from shutdown or power-on to full operation MAX98308 MAX98307, RIN = 10kI CONDITIONS Guaranteed by PSRR test MIN 2.6 1.85 0.225 78 78 67 25 50 1.3 22 40 ms 80 V kI dB TYP MAX 5.25 2.7 10 UNITS V mA µA Turn-On Time Input DC Bias Voltage Input Resistance (MAX98308) ����������������������������������������������������������������� Maxim Integrated Products 3 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier ELECTRICAL CHARACTERISTICS (continued) VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8I + 68FH between OUT+ and OUT-, (MAX98307 RIN+ = RIN- = 10kI, RFB+ = RFB- = 20kI), CIN+ = CIN- = 0.33FF, AV = 14.5dB, AC measurement bandwidth 20Hz to 20kHz, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25NC.) (Notes 2, 3) PARAMETER SYMBOL CONDITIONS GAIN = short to GND Voltage Gain (MAX98308) GAIN = 100kI pulldown to GND AV GAIN = short to PVDD GAIN = 100kI pullup to PVDD GAIN = unconnected Common-Mode Rejection Ratio (MAX98308) CMRR fIN = 1kHz ZL = 8I + 68mH, VPVDD = 3.6V fIN = 1kHz, THD+N = 1% ZL = 8I + 68mH, VPVDD = 4.2V ZL = 8I + 68mH, VPVDD = 5.0V ZL = 8I + 68mH, VPVDD = 3.6V fIN = 1kHz, THD+N = 10% ZL = 8I + 68mH, VPVDD = 4.2V ZL = 8I + 68mH, VPVDD = 5.0V ZSPK = 8I + 68mH, VPVDD = 3.6V THD+N ≤ 1% Output Power (MAX98308) POUT ZSPK = 8I + 68mH, VPVDD = 4.2V ZSPK = 8I + 68mH, VPVDD = 5.0V ZSPK = 8I + 68mH, VPVDD = 3.6V ZSPK = 8I + 68mH, VPVDD = 4.2V MIN 20 17 14 11 8 TYP 20.5 17.5 14.5 11.5 8.5 65 1.54 2 2.85 W 1.77 2.3 3.3 1.4 1.92 2.7 1.57 2.13 W MAX 21 18 15 12 9 dB dB UNITS Output Power (MAX98307) POUT THD+N ≤ 10% ����������������������������������������������������������������� Maxim Integrated Products 4 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier ELECTRICAL CHARACTERISTICS (continued) VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8I + 68FH between OUT+ and OUT-, (MAX98307 RIN+ = RIN- = 10kI, RFB+ = RFB- = 20kI), CIN+ = CIN- = 0.33FF, AV = 14.5dB, AC measurement bandwidth 20Hz to 20kHz, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25NC.) (Notes 2, 3) PARAMETER Total Harmonic Distortion Plus Noise Output Offset Voltage SYMBOL THD+N VOS CONDITIONS fIN = 1kHz, POUT = 1W TA = +25°C Peak voltage, A-weighted, 32 samples per second (Notes 4, 5) Into shutdown Out of shutdown MIN TYP 0.05 ±1 -65 dBV -65 340 η ILIM VN VIH VIL TA = +25NC A-weighted 1.4 0.4 ±10 fIN = 1kHz, POUT at 500mW, THD+N = 0.02% fIN = 1kHz, POUT at 1W, THD+N = 0.05% Current Limit Output Noise LOGIC INPUT (SHDN) Input Voltage High Input Voltage Low Input Leakage Current Note Note Note Note 2: 3: 4: 5: 84 82 2 52 ARMS µVRMS V V µA kHz % ±5 MAX UNITS % mV Click-and-Pop Level KCP Output Switching Frequency Efficiency 100% production tested at TA = +25°C. Specifications over temperature limits are guaranteed by design. Testing performed with a resistive load in series with an inductor to simulate an actual speaker. For RL = 8I, L = 68FH. Amplifier inputs AC-coupled to GND. Specified at room temperature with an 8I resistive load in series with a 68FH inductive load connected across the BTL outputs. Mode transitions controlled by SHDN active-low shutdown control. ����������������������������������������������������������������� Maxim Integrated Products 5 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Typical Operating Characteristics (VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8ω + 68FH between OUT+ and OUT-, AV = 14.5dB (MAX98307 RIN+ = RIN- = 10kω, RFB+ = RFB- = 20kω), CIN+ = CIN- = 0.33µF, AC measurement bandwidth 20Hz to 20kHz.) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (MAX98307) MAX98307 toc01 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (MAX98307) MAX98307 toc02 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (MAX98307) VPVDD = 5V fIN = 100kHz MAX98307 toc03 100 10 THD+N (%) 1 0.1 0.01 0.001 0 VPVDD = 3.6V fIN = 100kHz 100 10 THD+N (%) 1 VPVDD = 4.2V fIN = 100kHz 100 10 THD+N (%) 1 fIN = 6kHz fIN = 1kHz fIN = 6kHz 0.1 fIN = 1kHz 0.01 fIN = 6kHz 0.1 0.01 fIN = 1kHz 0.001 0.5 1.0 1.5 2.0 2.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 OUTPUT POWER (W) OUTPUT POWER (W) 0.001 0 1 2 3 4 5 OUTPUT POWER (W) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (MAX98308) MAX98307 toc04 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (MAX98308) MAX98307 toc05 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER (MAX98308) VPVDD = 5V MAX98307 toc06 100 10 THD+N (%) 1 0.1 0.01 0.001 0 VPVDD = 3.6V fIN = 100kHz 100 10 THD+N (%) 1 0.1 0.01 0.001 VPVDD = 4.2V fIN = 100kHz 100 10 fIN = 100kHz THD+N (%) 1 0.1 0.01 0.001 fIN = 6kHz fIN = 1kHz fIN = 6kHz fIN = 1kHz fIN = 6kHz fIN = 1kHz 0.5 1.0 1.5 2.0 2.5 0 0.5 1.0 1.5 2.0 2.5 3.0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 OUTPUT POWER (W) OUTPUT POWER (W) OUTPUT POWER (W) ����������������������������������������������������������������� Maxim Integrated Products 6 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Typical Operating Characteristics (continued) (VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8ω + 68FH between OUT+ and OUT-, AV = 14.5dB (MAX98307 RIN+ = RIN- = 10kω, RFB+ = RFB- = 20kω), CIN+ = CIN- = 0.33µF, AC measurement bandwidth 20Hz to 20kHz.) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (MAX98307) MAX98307 toc07 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (MAX98307) MAX98307 toc08 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (MAX98307) VPVDD = 5V MAX98307 toc09 10 VPVDD = 3.6V 10 VPVDD = 4.2V 10 1 THD+N (%) 1 THD+N (%) 1 THD+N (%) 0.1 POUT = 1.3W 0.1 POUT = 1.6W 0.1 POUT = 2.4W 0.01 POUT = 300mW 0.001 10 100 1k FREQUENCY (kHz) 10k 100k 0.01 POUT = 500mW 0.001 10 100 1k FREQUENCY (kHz) 10k 100k 0.01 POUT = 700mW 0.001 10 100 1k FREQUENCY (kHz) 10k 100k TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (MAX98308) MAX98307 toc10 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (MAX98308) MAX98307 toc11 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY (MAX98308) VPVDD = 5V MAX98307 toc12 10 VPVDD = 3.6V 10 VPVDD = 4.2V 10 1 THD+N (%) 1 THD+N (%) 1 THD+N (%) 0.1 POUT = 1.1W 0.1 POUT = 1.6W 0.1 POUT = 2.4W 0.01 POUT = 300mW 0.001 10 100 1k FREQUENCY (kHz) 10k 100k 0.01 POUT = 500mW 0.001 10 100 1k FREQUENCY (kHz) 10k 100k 0.01 POUT = 700mW 0.001 10 100 1k FREQUENCY (kHz) 10k 100k ����������������������������������������������������������������� Maxim Integrated Products 7 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Typical Operating Characteristics (continued) (VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8ω + 68FH between OUT+ and OUT-, AV = 14.5dB (MAX98307 RIN+ = RIN- = 10kω, RFB+ = RFB- = 20kω), CIN+ = CIN- = 0.33µF, AC measurement bandwidth 20Hz to 20kHz.) OUTPUT POWER vs. LOAD RESISTANCE (MAX98307) MAX98307 toc13 OUTPUT POWER vs. LOAD RESISTANCE (MAX98307) MAX98307 toc14 OUTPUT POWER vs. LOAD RESISTANCE (MAX98307) 3.0 OUTPUT POWER (W) 2.5 1.6 1.4 OUTPUT POWER (W) 1.2 1.0 0.8 0.6 0.4 0.2 0 1 10 VPVDD = 3.6V fIN = 1kHz THD+N = 10% 2.0 OUTPUT POWER (W) 1.5 1.0 0.5 0 VPVDD = 4.2V fIN = 1kHz THD+N = 10% VPVDD = 5V fIN = 1kHz THD+N = 10% 2.0 1.5 1.0 0.5 0 THD+N = 1% THD+N = 1% THD+N = 1% 100 1k 1 10 100 1k 1 10 100 1k LOAD RESISTANCE (I) LOAD RESISTANCE (I) LOAD RESISTANCE (I) OUTPUT POWER vs. LOAD RESISTANCE (MAX98308) MAX98307 toc16 OUTPUT POWER vs. LOAD RESISTANCE (MAX98308) MAX98307 toc17 OUTPUT POWER vs. LOAD RESISTANCE (MAX98308) 3.0 OUTPUT POWER (mW) 2.5 2.0 THD+N = 10% 1.5 1.0 0.5 0 VPVDD = 5V fIN = 1kHz MAX98307 toc18 1.6 1.4 OUTPUT POWER (W) 1.2 1.0 0 0.8 0.6 0.2 0 1 10 100 2.5 2.0 OUTPUT POWER (W) 1.5 VPVDD = 3.6V fIN = 1kHz THD+N = 10% VPVDD = 4.2V fIN = 1kHz 3.5 THD+N = 10% 1.0 0.5 0 THD+N = 1% THD+N = 1% THD+N = 1% 1k 1 10 100 1k 1 10 100 1k LOAD RESISTANCE (I) LOAD RESISTANCE (I) LOAD RESISTANCE (I) ����������������������������������������������������������������� Maxim Integrated Products 8 MAX98307 toc15 1.8 2.5 3.5 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Typical Operating Characteristics (continued) (VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8ω + 68FH between OUT+ and OUT-, AV = 14.5dB (MAX98307 RIN+ = RIN- = 10kω, RFB+ = RFB- = 20kω), CIN+ = CIN- = 0.33µF, AC measurement bandwidth 20Hz to 20kHz.) OUTPUT POWER vs. SUPPLY VOLTAGE (MAX98307) MAX98307 toc19 MAX98307 toc20 3.5 OUTPUT POWER (W) 3.0 2.5 2.0 1.5 1.0 0.5 0 2.6 3.0 3.4 3.8 4.2 4.6 SUPPLY VOLTAGE (V) THD+N = 1% THD+N = 10% fIN = 1kHz fIN = 1kHz 3.0 OUTPUT POWER (W) 2.5 2.0 1.5 1.0 0.5 THERMALLY LIMITED GAIN = VPVDD GAIN = PGND GAIN = 100kI TO PGND 20 AMPLITUDE (dB) 10 GAIN = 100kI TO VPVDD 0 -10 -20 GAIN = UNCONNECTED THD+N = 10% THD+N = 1% 5.0 5.4 0 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4 SUPPLY VOLTAGE (V) 10 100 1k 10k FREQUENCY (kHz) 100k EFFICIENCY vs. OUTPUT POWER (MAX98307) MAX98307 toc22 EFFICIENCY vs. OUTPUT POWER (MAX98307) MAX98307 toc23 EFFICIENCY vs. OUTPUT POWER (MAX98307) 80 70 EFFICIENCY (%) 60 50 40 30 20 10 0 VPVDD = 5V fIN = 1kHz MAX98307 toc24 90 80 70 EFFICIENCY (%) 60 50 40 30 20 10 0 0 0.2 0.4 0.6 0.8 1.0 VPVDD = 3.6V fIN = 1kHz 90 80 70 EFFICIENCY (%) 60 50 40 30 20 10 0 VPVDD = 4.2V fIN = 1kHz 90 1.2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0 0.5 1.0 1.5 2.0 2.5 OUTPUT POWER (W) OUTPUT POWER (W) OUTPUT POWER (W) ����������������������������������������������������������������� Maxim Integrated Products 9 MAX98307 toc21 4.0 OUTPUT POWER vs. SUPPLY VOLTAGE (MAX98308) 3.5 GAIN vs. FREQUENCY (MAX98308) 30 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Typical Operating Characteristics (continued) (VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8ω + 68FH between OUT+ and OUT-, AV = 14.5dB (MAX98307 RIN+ = RIN- = 10kω, RFB+ = RFB- = 20kω), CIN+ = CIN- = 0.33µF, AC measurement bandwidth 20Hz to 20kHz.) EFFICIENCY vs. OUTPUT POWER (MAX98308) MAX98307 toc25 EFFICIENCY vs. OUTPUT POWER (MAX98308) MAX98307 toc26 EFFICIENCY vs. OUTPUT POWER (MAX98308) 80 70 EFFICIENCY (%) 60 50 40 30 20 10 0 VPVDD = 5V fIN = 1kHz MAX98307 toc27 MAX98307 toc30 90 80 70 EFFICIENCY (%) 60 50 40 30 20 10 0 0 0.2 0.4 0.6 0.8 1.0 VPVDD = 3.6V fIN = 1kHz 90 80 70 EFFICIENCY (%) 60 50 40 30 20 10 0 VPVDD = 4.2V fIN = 1kHz 90 1.2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0 0.5 1.0 1.5 2.0 2.5 OUTPUT POWER (W) OUTPUT POWER (W) OUTPUT POWER (W) SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX98307 toc28 SHUTDOWN CURRENT vs. SUPPLY VOLTAGE MAX98307 toc29 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY 0 -10 -20 -30 PSRR (dB) -40 -50 -60 -70 -80 -90 VRIPPLE = 200mVP-P 3.0 2.5 SUPPLY CURRENT (mA) 2.0 1.5 1.0 0.5 0 2.5 3.0 3.5 4.0 4.5 5.0 VPVDD = 3.6V fIN = 1kHz 400 350 SHUTDOWN CURRENT (nA) 300 250 200 150 100 50 0 5.5 2.5 3.0 3.5 4.0 4.5 5.0 5.5 10 100 1k FREQUENCY (Hz) 10k 100k SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) ���������������������������������������������������������������� Maxim Integrated Products 10 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Typical Operating Characteristics (continued) (VPVDD = VCC = VSHDN = 3.6V, VPGND = VGND = 0V, ZL = 8ω + 68FH between OUT+ and OUT-, AV = 14.5dB (MAX98307 RIN+ = RIN- = 10kω, RFB+ = RFB- = 20kω), CIN+ = CIN- = 0.33µF, AC measurement bandwidth 20Hz to 20kHz.) COMMON-MODE REJECTION RATIO vs. FREQUENCY (MAX98307) MAX98307 toc31 COMMON-MODE REJECTION RATIO vs. FREQUENCY (MAX98308) -10 -20 CMRR (dB) -30 -40 -50 -60 -70 -80 MAX98307 toc32 0 -10 -20 -30 CMRR (dB) -40 -50 -60 -70 -80 -90 10 100 1k FREQUENCY (Hz) fIN = 1kHz 0 10k 100k 10 100 1k FREQUENCY (Hz) 10k 100k STARTUP RESPONSE MAX98307 toc33 SHUTDOWN RESPONSE MAX98307 toc34 WIDEBAND vs. FREQUENCY -20 OUTPUT MAGNITUDE (dBV) -40 -60 -80 -100 -120 -140 -160 VPVDD = 3.6V MAX98307 toc35 0 VSHDN 2V/div VSHDN 2V/div ISPEAKER 100mA /div ISPEAKER 100mA /div 20ms/div 20ms/div -180 100k 1G 10G 100G FREQUENCY (Hz) INBAND OUTPUT SPECTRUM VPVDD = 3.6V -20 OUTPUT MAGNITUDE (dBV) -40 -60 -80 -100 -120 -140 10 100 1k FREQUENCY (Hz) 10k 100k MAX98307 toc36 CLIPPING WAVEFORM 10% THD+N MAX98307 toc37 0 OUT+ 1V/div OUT1V/div 200µs/div ���������������������������������������������������������������� Maxim Integrated Products 11 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Pin/Bump Configurations FB+ FB- IN+ TOP VIEW TOP VIEW (BUMPS SIDE DOWN) 1 IN- 12 11 10 9 MAX98308 2 3 GND PVDD 4 + VCC 13 PVSS 14 C1N 15 C1P 16 8 7 N.C. SVSS PGND OUTC PVSS IN+ INPGND A C1P OUT+ MAX98307 + 1 SHDN 2 GND 3 PVDD EP B C1N SHDN GAIN OUT- 6 5 4 OUT+ WLP TQFN Pin/Bump Description PIN MAX98307 1 2 3 4 5 6 7 8 9 10 11 12 — 13 14 15 16 BUMP MAX98308 B2 A2 A3 A4 B4 C4 — — — C3 C2 — B3 — C1 B1 A1 NAME SHDN GND PVDD OUT+ OUTPGND SVSS N.C. FBININ+ FB+ GAIN VCC PVSS C1N C1P FUNCTION Active-Low Shutdown. Connect to GND for shutdown. Connect to PVDD for normal operation. Substrate and Signal Ground Power and Charge-Pump Supply. Bypass to PGND with a 0.1FF capacitor. Positive Amplifier Output Negative Amplifier Output Power Ground Amplifier Negative Power Supply. Connect to PVSS (MAX98307). No Connection. Not internally connected. Connect to GND or leave unconnected. Negative Amplifier Feedback Negative Amplifier Input Positive Amplifier Input Positive Amplifier Feedback See Table 1 MAX98308 Gain Configuration for more information. Signal Supply Charge-Pump Output. Connect a 10FF capacitor between PVSS and PGND. Charge-Pump Flying Capacitor Negative Terminal. Connect a 4.7FF capacitor between C1N and C1P. Charge-Pump Flying Capacitor Positive Terminal. Connect a 4.7FF capacitor between C1N and C1P. ���������������������������������������������������������������� Maxim Integrated Products 12 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Detailed Description The MAX98307/MAX98308 fully differential mono Class DG multilevel power amplifiers with integrated inverting charge pumps offer highly efficient, high-power audio solutions for portable applications. The new Class DG multilevel modulation scheme extends the dynamic range of the output signal by employing a charge-pump-generated negative rail, which is used as needed to extend the supply range. When the negative rail is not needed, the output is drawn entirely from the standard supply. This scheme results in high efficiency over a wide output power range. The power amplifier incorporates active emissions limiting edge rate and overshoot control circuitry in combination with the multilevel output modulation scheme to greatly reduce EMI. These features eliminate the need for output filtering as compared to traditional Class D amplifiers, which reduces an application’s component count. The MAX98307 has an adjustable gain set by external resistors. The MAX98308 has preset fixed gains of 8.5dB, 11.5dB, 14.5dB, 17.5dB, and 20.5dB set by a gain select input (GAIN). The ICs’ filterless Class DG multilevel amplifiers feature a proprietary Maxim output stage that offers higher efficiency over a greater output power range than previous amplifiers. The amplifier combines Class D switching output efficiency and Class G supply level shifting with a multilevel output modulation scheme that with a 5V supply has efficiency better than 80% efficiency over the 0.35W to 2.2W output range. The Class DG multilevel output stage uses pulse-width modulation (PWM), a rail-to-rail digital output signal with variable duty cycle, to approximate an analog input signal as in a Class D amplifier. Rail-to-rail operation ensures that any dissipation at the output is due solely to the RDS(ON) of the power output MOSFETs. The Class DG multilevel output stage also senses the magnitude of the output signal and switches the supply rails as needed to more efficiently supply the required signal power. For a low output signal swing requirement (below the battery supply rail VPVDD), the output range is between VPVDD and ground. When output swing above VPVDD is required, VPVSS, an internal inverting charge-pump-generated negative rail replaces ground as the lower supply. The high output swing range is then VPVDD to VPVSS, approximately double the low swing range. This approach efficiently manages power consumption by switching the operating rails as needed according to the output swing requirements. Additionally, multilevel output modulation is employed in to draw the maximum possible power from the lower impedance battery supply rail, VPVDD, rather than the higher impedance charge-pump-generated rail VPVSS. This is accomplished by generating PWM signals that swing from ground to VPVDD or from ground to VPVSS at either end of the bridge tied load (BTL) rather than continually swinging from VPVDD to VPVSS. The signals are modulated in such a way that VPVSS is used only as necessary to generate low-end signal swing. These combined operations ensure that power dissipation due to RDS(ON) loss and charge-pump impedance is minimized, and that efficiency and output power is maximized across the audio range. Class DG multilevel operation is shown as Figure 1. Class DG Multilevel Operation MAX98307 fig01 OUT+ 5V/div OUT5V/div OUT+ - OUT10V/div 400µs /div Figure 1. Class DG Multilevel Operation ���������������������������������������������������������������� Maxim Integrated Products 13 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier EFFICIENCY vs. OUTPUT POWER 80 70 EFFICIENCY (%) 60 50 40 30 20 10 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 OUTPUT POWER (W) MAX98307 fig02 90 The Class DG multilevel efficiency compares favorably with Class AB and Class G amplifiers as shown in Figure 2. Note that efficiency at 1W is 85%. Traditional Class D amplifiers require the use of external LC filters, or shielding, to meet electromagnetic-interference (EMI) regulation standards. The active emissions limiting edge-rate control circuitry and Class DG multilevel modulation scheme reduce EMI emissions without the need for external filtering components, while maintaining high efficiency (see Figure 3). If the output current of the speaker amplifier exceeds the current limit, the ICs disable the outputs for approximately 100Fs. After 100Fs, the outputs are reenabled. If the fault condition still exists, the ICs continue to disable and reenable the outputs until the fault condition is removed. MAX98307/MAX98308 CLASS DG MULTILEVEL AMPLIFIER EMI Filterless Output Stage CLASS G AMPLIFIER CLASS AB AMPLIFIER VPVDD = 5V fIN = 1kHz Amplifier Current Limit Figure 2. Class DG Multilevel vs. Typical Class G and Class AB Amplifier Efficiency 90 70 50 EN55022B LIMIT 30 10 VERTICAL -10 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) HORIZONTAL Figure 3. EMI Performance with VPVDD = 5V, 12in of Speaker Cable, No Output Filter ���������������������������������������������������������������� Maxim Integrated Products 14 EMISSIONS LEVEL (dBµV/m) MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier The speaker amplifier features Maxim’s comprehensive click-and-pop suppression. During startup, the clickand-pop suppression circuitry reduces any audible transient sources internal to the device. When entering shutdown, the differential speaker outputs quickly and simultaneously ramp down to PGND. The ICs automatically enter thermal shutdown when the die temperature is greater than +160NC and reactivate at less than +135NC. Additionally, if the outputs are shorted to each other or either rail, the amplifier prevents catastrophic loss by disabling the outputs. The ICs feature a low-power shutdown mode, drawing less than 0.225FA (typ) supply current. Drive SHDN low to put the IC into the shutdown state. Click-and-Pop Suppression feature differential amplifiers, their voltage gain is set in differing manners. The MAX98307 employs external feedback resistors as shown in Figure 4. Voltage gain of the input amplifier is set as: R  = 20log FB  (dB) + 8.5dB AV  RIN  where AV is the desired voltage gain in decibels. RIN+ should be equal to RIN-, and RFB+ should be equal to RFB-. In differential input configurations, the common-mode rejection ratio (CMRR) is primarily limited by the external resistor and capacitor matching. Ideally, to achieve the highest possible CMRR, the following external components should be selected where: R FB+ R FB= RIN+ RINand CIN+ = CINThe gain of the MAX98308 is selectable by connecting the gain-select bump GAIN as described in Table 1. Thermal and Short Circuit Protection Shutdown Applications Information Traditional Class DG amplifiers require an output filter. The filter adds cost and size, as well as decreases efficiency and THD+N performance. The ICs’ active emissions limiting and Class DG multilevel output modulation allow for filterless operation while reducing external component count, and thereby, cost. Because the switching frequency of the ICs is well beyond the bandwidth of most speakers, voice coil movement due to the switching frequency is very small. Use a speaker with a series inductance > 10FH. Typical 8I speakers exhibit series inductances in the 20FH to 100FH range. The ICs feature a differential input configuration, making the device compatible with many codecs and offering improved noise immunity as compared to single-ended input amplifiers. In devices such as mobile phones, noisy digital signals can be picked up by an amplifier’s input traces. A differential amplifier amplifies the difference of the two inputs, while signals common to both inputs, such as switching noise, are rejected. While both ICs Filterless Class DG Operation FB+ MAX98307 RFB+ RIN+ IN+ CLASS DG OUTPUT STAGE Differential Input Amplifier RIN- IN- RFBFB- Figure 4. Setting the Voltage Gain of the MAX98307 ���������������������������������������������������������������� Maxim Integrated Products 15 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Table 1. MAX98308 Gain Configuration GAIN Unconnected 100kI to VPVDD Short to VPVDD 100kI to PGND Short to PGND PREAMPLIFIER GAIN (dB) 0 3 6 9 12 OVERALL GAIN (dB) 8.5 11.5 14.5 17.5 20.5 Note: For both ICs, the Class DG output stage has a fixed gain of 8.5dB. Any gain or attenuation set by the external input stage resistors adds to or subtracts from this fixed gain. Component Selection Power-Supply Input (PVDD) PVDD powers the speaker amplifier and has a range of 2.6V to 5.25V. Bypass PVDD with 0.1FF and 10FF capacitors in parallel to PGND. Apply additional bulk capacitance at the device if long input traces between PVDD and the supply are used. Input Coupling Capacitors The AC-coupling capacitors (CIN) and input resistors (RIN) form highpass filters that remove any DC bias from an input signal. See the MAX98307 Typical Application Circuit and MAX98308 Typical Application Circuit. CIN prevents any DC components from the input signal source appearing at the amplifier outputs. The -3dB point of the highpass filter, assuming zero source impedance due to the input signal source, is given by: f 3dB = − Charge-Pump Flying Capacitor The value of the charge-pump flying capacitor affects the load regulation and output resistance of the charge pump. A charge-pump flying capacitor value that is too small (less than 1FF) degrades the amplifier’s ability to provide sufficient current drive. Increasing the value of this flying capacitor and decreasing the ESR improves load regulation and reduces the charge-pump output impedance, which improves the output power and efficiency of the amplifier. A 4.7FF or greater value, low-ESR capacitor is recommended. Charge-Pump Hold Capacitor The charge-pump hold capacitor value and ESR directly affect the ripple at the charge-pump rail, PVSS. Increasing the charge-pump hold capacitor value reduces output ripple. Likewise, decreasing the ESR of this capacitor reduces both ripple and output resistance. A 10FF or greater value, low-ESR capacitor is recommended. Proper layout and grounding are essential for optimum performance. Good grounding improves audio performance and prevents switching noise from coupling into the audio signal. Use wide, low-resistance output traces. As load impedance decreases, the current drawn from the device increases. At higher current, the resistance of the output traces decrease the power delivered to the load. For example, if 2W is delivered from the device output to an 8I load through 100mI of total speaker trace, 1.97W is delivered to the speaker. If power is delivered through 10mI of total speaker trace, 1.998W is delivered to the speaker. Wide output, supply, and ground traces also improve the power dissipation of the device. The ICs are inherently designed for excellent RF immunity. For best performance, add ground fills around all signal traces on top or bottom PCB planes. 1 2π × RIN × CIN Layout and Grounding Choose CIN so that f-3dB is well below the lowest frequency of interest. Setting f-3dB too high affects the amplifier’s low-frequency response. Use capacitors with adequately low voltage coefficient (X5R or X7R recommended) for best low frequency THD+N performance. Charge-Pump Capacitor Selection Use capacitors with an equivalent series resistance (ESR) less than 50mI for optimum performance. LowESR ceramic capacitors minimize the output resistance of the charge pump. For best performance over the extended temperature range, select capacitors with an X7R dielectric and a rated voltage of at least 6.3V. ���������������������������������������������������������������� Maxim Integrated Products 16 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Class DG multilevel amplifiers provide much better efficiency and thermal performance than a comparable Class AB or Class G amplifiers. However, the system’s thermal performance must be considered with realistic expectations and include consideration of many parameters. This section examines Class DG multilevel amplifiers using general examples to illustrate good design practices. MAX98307 (TQFN) Applications Information The exposed pad is the primary route of keeping heat away from the IC. With a bottom-side exposed pad, the PCB and its copper becomes the primary heatsink for the Class DG multilevel amplifier. Solder the exposed pad to a large copper polygon. Add as much copper as possible from this polygon to any adjacent pin on the amplifier as well as to any adjacent components, provided these connections are at the same potential. These copper paths must be as wide as possible. Each of these paths contributes to the overall thermal capabilities of the system. Thermal Considerations The copper polygon to which the exposed pad is attached should have multiple vias to the opposite side of the PCB. Make this polygon as large as possible within the system’s constraints for signal routing. MAX98308 (WLP) Applications Information For the latest application details on WLP construction, dimensions, tape carrier information, PCB techniques, bump-pad layout, and recommended reflow temperature profile, as well as the latest information on reliability testing results, refer to Application Note 1891: Wafer-Level Packaging (WLP) and Its Applications. Ordering Information PART MAX98307ETE+ MAX98308EWC+** GAIN SET External Internal PIN-PACKAGE 16 TQFN-EP* 12 WLP Note: All devices operate over the -40°C to +85°C temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. **Future product–contact factory for availability. ���������������������������������������������������������������� Maxim Integrated Products 17 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Package Information For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE 16 TQFN-EP 12 WLP PACKAGE CODE T1633-5 W121A1+1 OUTLINE NO. 21-0136 21-0449 LAND PATTERN NO. 90-0032 Refer to Application Note 1891 ���������������������������������������������������������������� Maxim Integrated Products 18 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. ���������������������������������������������������������������� Maxim Integrated Products 19 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. ���������������������������������������������������������������� Maxim Integrated Products 20 MAX98307/MAX98308 3.3W Mono Class DG Multilevel Audio Amplifier Revision History REVISION NUMBER 0 1 2 REVISION DATE 6/11 8/11 9/11 Initial release Updated output power conditions in the Electrical Characteristics table Updated Electrical Characteristics table and TOC 20 DESCRIPTION PAGES CHANGED — 4 2, 4, 8 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. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 21 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.