19-0701; Rev 5; 3/10 KIT ATION EVALU E L B AVAILA 2.4W, Single-Supply, Class G Power Amplifier The MAX9730 features a mono Class G power amplifier with an integrated inverting charge-pump power supply. The charge pump can supply up to 500mA of peak output current over a 2.7VDC to 5.5VDC supply voltage range, guaranteeing up to 2.4W output power into an 8Ω load. The 2.4W output power allows for transient audio content to remain unclipped as the battery rail collapses over time. The MAX9730 maximizes battery life by offering highperformance efficiency. Maxim’s proprietary output stage provides efficiency levels greater than Class AB devices without the EMI penalties commonly associated with Class D amplifiers. High efficiency allows the MAX9730 to be packaged in a WLP package without derating the output power handling capability. The device utilizes fully differential inputs and outputs, comprehensive click-and-pop suppression, shutdown control, and soft-start circuitry. The MAX9730 is fully specified over the -40°C to +85°C extended temperature range and is available in ultra-small, lead-free, 20-bump WLP (2mm x 2.5mm) and 28-pin TQFN (4mm x 4mm) packages. Applications MP3 Players Personal Media Players Handheld Gaming Consoles Cell Phones Smartphones Notebook Computers Features o 2.7V to 5.5V Operation o Integrated Charge-Pump Power Supply o 63% Efficiency (VCC = 5V, POUT = 1W) o 2.4W Output Power into 8Ω at VCC = 5V o Clickless/Popless Operation o Small Thermally Efficient Packages 2mm x 2.5mm 20-Bump WLP 4mm x 4mm 28-Pin TQFN Ordering Information PIN-PACKAGE TEMP RANGE MAX9730EWP+TG45 PART 20 WLP -40°C to +85°C MAX9730ETI+ 28 TQFN-EP* -40°C to +85°C +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel. G45 indicates protective die coating. *EP = Exposed pad. Typical Application Circuit/Functional Diagram and Pin Configurations appear at end of data sheet. Simplified Block Diagram 2.7V TO 5.5V VCC CPVDD FB+ MAX9730 CIN RIN+ RFB+ IN+ IN- CIN RIN- CLASS G OUTPUT STAGE + - OUT+ OUT- RFBCHARGE PUMP FBGND CPGND ________________________________________________________________ Maxim Integrated Products 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. 1 MAX9730 General Description MAX9730 2.4W, Single-Supply, Class G Power Amplifier ABSOLUTE MAXIMUM RATINGS (Voltages with respect to GND.) VCC, CPVDD .............................................................-0.3V to +6V PVSS, SVSS ...............................................................-6V to +0.3V CPGND..................................................................-0.3V to +0.3V OUT+, OUT-...................................(SVSS - 0.3V) to (VCC + 0.3V) IN+, IN-, FB+, FB- ......................................-0.3V to (VCC + 0.3V) C1N..........................................(PVSS - 0.3V) to (CPGND + 0.3V) C1P.......................................(CPGND - 0.3V) to (CPVDD + 0.3V) FS, SHDN ...................................................-0.3V to (VCC + 0.3V) Continuous Current Into/Out of OUT+, OUT-, VCC, GND, SVSS .....................................800mA CPVDD, CPGND, C1P, C1N, PVSS .................................800mA Any Other Pin ..................................................................20mA Continuous Power Dissipation (TA = +70°C) 20-Bump WLP (derate 10.3mW/°C above +70°C)........827mW 28-Pin TQFN (derate 20.8mW/°C above +70°C) ........1667mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) ................................+300°C Bump Temperature (soldering) Reflow............................+260°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 (VCC = VCPVDD = V SHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS GENERAL Supply Voltage Range VCC Quiescent Current ICC Inferred from PSRR test 2.7 8 Chip Power Dissipation PDISS VOUT = 2.8VRMS, f = 1kHz, RL = 8Ω 0.9 Shutdown Current ISHDN SHDN = GND 0.3 Time from shutdown or power-on to full operation 50 Turn-On Time Input DC Bias Voltage Charge-Pump Oscillator Frequency (Slow Mode) Maximum Capacitive Load tON VBIAS fOSC V 12 mA W 5 1.1 1.24 1.4 ILOAD = 0mA (slow mode) 55 83 110 ILOAD > 100mA (normal mode) 230 330 430 VIH 1.4 200 VIL V kHz pF 0.4 SHDN Input Leakage Current µA ms IN_ inputs CL SHDN Input Threshold (Note 3) 5.5 ±1 V µA SPEAKER AMPLIFIER Output Offset Voltage Common-Mode Rejection Ratio Click-and-Pop Level 2 VOS CMRR VCP TA = +25°C ±3 TMIN ≤ TA ≤ TMAX ±15 ±20 mV fIN = 1kHz (Note 4) 68 dB Peak voltage into/out of shutdown A-weighted, 32 samples per second (Notes 5, 6) -52 dBV _______________________________________________________________________________________ 2.4W, Single-Supply, Class G Power Amplifier (VCC = VCPVDD = V SHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) PARAMETER Voltage Gain SYMBOL AV Continuous Output Power POUT CONDITIONS (Notes 4, 7) THD+N = 1%, f = 1kHz, RL = 8Ω f = 1kHz, 1% THD+N, ZL = 1µF + 10Ω Output Voltage VOUT f = 10kHz, 1% THD+N, ZL = 1µF + 10Ω PSRR Signal-to-Noise Ratio Dynamic Range Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: THD+N SNR DR MAX UNITS 12 12.5 dB 2.4 VCC = 4.2V 1.67 VCC = 3.6V 1.25 VCC = 3.0V 0.8 VCC = 5V 7.1 VCC = 4.2V 5.9 VCC = 3.6V 5.1 VCC = 3.0V 4.2 VCC = 5V 6.5 VCC = 4.2V 5.4 VCC = 3.6V 4.7 VCC = 3.0V 3.8 63 77 f = 1kHz, 200mVP-P ripple 77 0.007 RL = 8Ω, VOUT = 1kHz / 1VRMS 0.12 (Note 9) VRMS dB 58 RL = 8Ω, VOUT = 1kHz / 400mVRMS VOUT = 0.5VRMS, inputs to GND by C1N, A-weighted W 77 f = 217Hz, 200mVP-P ripple f = 20kHz, 200mVP-P ripple Total Harmonic Distortion Plus Noise TYP VCC = 5V VCC = 2.7V to 5.5V Power-Supply Rejection Ratio (Note 4) MIN 11.5 95 22Hz to 22kHz 96 A-weighted 99 % dB dB All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design. Testing performed with resistive and inductive loads to simulate an actual speaker load. For dynamic speakers, RL = 8Ω, 68µH. Designed for 1.8V logic. RIN_ and RFB_ have 0.5% tolerance. Amplifier inputs AC-coupled to GND. Testing performed at room temperature with 8Ω resistive load in series with 68µH inductive load connected across BTL output for speaker amplifier. Mode transitions are controlled by SHDN. VCP is the peak output transient expressed in dBV. Voltage gain is defined as: [VOUT+ - VOUT-] / [VIN+ - VIN-]. Mode A tone burst tested at full amplitude for one cycle and half amplitude for nine cycles. Mode B tone burst tested at full amplitude for three cycles and half amplitude for seven cycles. Full amplitude is defined as 1% THD+N at full battery (VCC = 4.2V). Electrical Characteristics table targets must be met at THD+N = 1% for one cycle (Mode A) and THD+N < 5% for three cycles (Mode B). Dynamic range is calculated by measuring the RMS voltage difference between a -60dBFS output signal and the noise floor, then adding 60dB. Full scale is defined as the output signal needed to achieve 1% THD+N. _______________________________________________________________________________________ 3 MAX9730 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = VCPVDD = VSHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF, RL = 8Ω; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) POUT = 0.37W 0.1 1 10 MAX9730 toc03 0.001 0.01 100 POUT = 0.83W 0.01 0.001 0.01 POUT = 2.08W 0.1 0.01 0.001 0.1 1 10 0.01 100 0.1 1 10 100 FREQUENCY (kHz) FREQUENCY (kHz) FREQUENCY (kHz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER VCC = 3.6V fIN = 10kHz fIN = 10kHz 1 fIN = 1kHz 0.1 0.01 0.01 0.01 fIN = 20Hz 0.001 0.001 0.5 1.0 1.5 0.1 fIN = 20Hz fIN = 20Hz 0.001 fIN = 1kHz THD+N (%) THD+N (%) fIN = 1kHz 0 VCC = 5V 1 0.1 MAX9730 toc06 fIN = 10kHz 10 MAX9730 toc05 VCC = 3V 1 10 MAX9730 toc04 10 0 0.5 1.0 1.5 0 2.0 0.5 1.0 1.5 2.0 2.5 OUTPUT POWER (W) OUTPUT POWER (W) OUTPUT POWER (W) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY POWER EFFICIENCY vs. OUTPUT POWER POWER EFFICIENCY vs. OUTPUT POWER -20 70 70 MAX9730 toc08 VRIPPLE = 200mVP-P MAX9730 toc07 0 -10 60 60 50 -40 -50 -60 3.5 50 EFFICIENCY (%) EFFICIENCY (%) -30 3.0 MAX9730 toc09 THD+N (%) 1 0.1 POUT = 0.33W 0.01 VCC = 5V THD+N (%) 0.1 10 POUT = 0.93W 1 POUT = 0.69W THD+N (%) THD+N (%) VCC = 3.6V MAX9730 toc02 VCC = 3V 1 10 MAX9730 toc01 10 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY PSRR (dB) MAX9730 2.4W, Single-Supply, Class G Power Amplifier 40 30 20 40 30 20 -70 10 -80 -90 0 0.01 0.1 1 FREQUENCY (kHz) 4 10 VCC = 3V fIN = 1kHz 10 100 VCC = 3.6V fIN = 1kHz 0 0 1.0 OUTPUT POWER (W) 1.5 0 0.5 1.0 OUTPUT POWER (W) _______________________________________________________________________________________ 1.5 2.4W, Single-Supply, Class G Power Amplifier POWER EFFICIENCY vs. OUTPUT POWER MAX9730 toc12 MAX9730 toc11 MAX9730 toc10 60 SHDN 5V/div SHDN 5V/div OUT+ - OUT500mV/div OUT+ - OUT500mV/div 50 40 30 20 10 VCC = 5V fIN = 1kHz 0 0 1 3 2 10ms/div 10ms/div OUTPUT POWER (W) SHUTDOWN CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT (mA) 8 6 4 MAX9730 toc14 10 1.0 0.9 SHUTDOWN CURRENT (μA) MAX9730 toc13 12 0.8 0.7 0.6 0.5 0.4 0.3 0.2 2 0.1 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 2.5 6.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) OUTPUT POWER vs. SUPPLY VOLTAGE OUTPUT POWER vs. LOAD RESISTANCE 3.0 MAX9730 toc15 4.0 3.5 3.0 3.0 SUPPLY VOLTAGE (V) OUTPUT POWER (W) 10% THD+N 2.5 2.0 1% THD+N 1.5 fIN = 1kHz POUT AT 1% THD+N 2.5 6.0 MAX9730 toc16 0 OUTPUT POWER (W) EFFICIENCY (%) SHUTDOWN WAVEFORM STARTUP WAVEFORM 70 2.0 VCC = 5V 1.5 1.0 1.0 0.5 0.5 VCC = 3.6V fIN = 1kHz 0 0 2.5 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5.5 6.0 0 20 40 60 80 100 LOAD RESISTANCE (Ω) _______________________________________________________________________________________ 5 MAX9730 Typical Operating Characteristics (continued) (VCC = VCPVDD = VSHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF, RL = 8Ω; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) Typical Operating Characteristics (continued) (VCC = VCPVDD = VSHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF, RL = 8Ω; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) PACKAGE THERMAL DISSIPATION AND OUTPUT POWER vs. TEMPERATURE POUT = 1W 18 16 OUT+ 5V/div 14 OUT5V/div 12 10 8 6 OUT+ - OUT10V/div 4 1% THD+N 2 0 100 1k 10k 100k 3.5 VCC = 5V 3.0 2.5 3.0 OUTPUT POWER 2.0 1.5 2.5 2.0 PACKAGE THERMAL DISSIPATION 1.5 1.0 1.0 0.5 0.5 0 10 200μs/div MAX9730 toc19 3.5 0 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 FREQUENCY (Hz) TEMPERATURE (°C) Pin Description PIN 6 TQFN WLP NAME FUNCTION 1 B2 SHDN 2, 5, 6, 8, 11, 17, 19, 23, 25, 28 — N.C. 3 A2 C1P 4 A3 CPVDD 7 A4 FB- Negative Amplifier Feedback 9 A5 IN- Negative Amplifier Input 10 B5 IN+ Positive Amplifier Input 12 B4 FB+ Positive Amplifier Feedback 13 C5 FS 14, 22 D1, D5 VCC Supply Voltage. Bypass with a 10µF capacitor to GND. 15, 21 C2, C4 SVSS Amplifier Negative Power Supply. Connect to PVSS. 16 D4 OUT- Negative Amplifier Output 18 D3 GND Ground 20 D2 OUT+ 24 C1 PVSS 26 B1 C1N 27 A1 CPGND EP — EP Shutdown No Connection. No internal connection. Charge-Pump Flying Capacitor, Positive Terminal. Connect a 4.7µF capacitor between C1P and C1N. Charge-Pump Positive Supply Charge-Pump Frequency Set. Connect a 100kΩ resistor from FS to GND to set the charge-pump switching frequency. Positive Amplifier Output Charge-Pump Output. Connect a 10µF capacitor between PVSS and CPGND. Charge-Pump Flying Capacitor, Negative Terminal. Connect a 4.7µF capacitor between C1N and C1P. Charge-Pump Ground. Connect to GND. Exposed Pad. Connect the TQFN EP to GND. _______________________________________________________________________________________ OUTPUT POWER (W) 20 PACKAGE THERMAL DISSIPATION (W) MAX9730 toc17 MAX9730 toc18 FREQUENCY RESPONSE CLASS G OUTPUT WAVEFORM GAIN (dB) MAX9730 2.4W, Single-Supply, Class G Power Amplifier 2.4W, Single-Supply, Class G Power Amplifier ply range. In this range, the operation of the device is identical to a traditional single-supply Class AB amplifier where: The MAX9730 Class G power amplifier with inverting charge pump is the latest in linear amplifier technology. The Class G output stage offers the performance of a Class AB amplifier while increasing efficiency to extend battery life. The integrated inverting charge pump generates a negative supply capable of delivering up to 500mA. ILOAD = IN1 As the output signal increases, so a wider supply is needed, the device begins its transition to the higher supply range (VCC to SVSS) for the large signals. To ensure a seamless transition between the low and high supply ranges, both of the lower transistors are on so that: ILOAD = IN1 + IN2 As the output signal continues to increase, the transition to the high supply is complete. The device then operates in the higher supply range, where the operation of the device is identical to a traditional dual-supply Class AB amplifier where: The Class G output stage and the inverting charge pump allow the MAX9730 to deliver an output power that is up to four times greater than a traditional single-supply linear amplifier. This allows the MAX9730 to maintain 0.8W into an 8Ω load as the battery rail collapses. Class G Operation and Efficiency The MAX9730 Class G amplifier is a linear amplifier that operates within a low (VCC to GND) and high (VCC to SVSS) supply range. Figure 1 illustrates the transition from the low to high supply range. For small signals, the device operates within the lower (VCC to GND) sup- ILOAD = IN2 During operation, the output common-mode voltage of the MAX9730 adjusts dynamically as the device transitions between supply ranges. BTL CLASS G SUPPLY TRANSITION VCC VCC IP ON P VCC IP ON RL IN1 N1 ON N2 OFF P IP ON RL IN1 IN2 N1 ON N2 ON P RL IN2 N1 OFF N2 ON SVSS SVSS SVSS LOW SUPPLY RANGE OPERATION IP = IN1 SUPPLY TRANSITION IP = IN1 + IN2 HIGH SUPPLY RANGE OPERATION IP = IN2 Figure 1. Class G Supply Transition _______________________________________________________________________________________ 7 MAX9730 Detailed Description Utilizing a Class G output stage with an inverting charge pump allows the MAX9730 to realize a 2.4W output power with a 5V supply. 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 MAX9730 still exhibits 50% efficiency under the same conditions. Inverting Charge Pump The MAX9730 features an integrated charge pump with an inverted supply rail that can supply greater than 700mA over the positive 2.7V to 5.5V supply range. In the case of the MAX9730, the charge pump generates the negative supply rail (PVSS) needed to create the higher supply range, which allows the output of the device to operate over a greater dynamic range as the battery supply collapses over time. Shutdown Mode The MAX9730 has a shutdown mode that reduces power consumption and extends battery life. Driving SHDN low places the MAX9730 in a low-power (0.3µA) shutdown mode. Connect SHDN to V CC for normal operation. Click-and-Pop Suppression The MAX9730 Class G amplifier features Maxim’s comprehensive, industry-leading click-and-pop suppression. During startup, the click-and-pop suppression circuitry eliminates any audible transient sources internal to the device. Applications Information Differential Input Amplifier The MAX9730 features a differential input configuration, making the device 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 common-mode noise. A differential input amplifier amplifies the difference of the two inputs, and signals common to both inputs are canceled out. When configured for differential inputs, the voltage gain of the MAX9730 is set by: ⎡ ⎛ RFB _ ⎞ ⎤ A V = 20 log⎢4 × ⎜ ⎟ ⎥ (dB) ⎢⎣ ⎝ RIN _ ⎠ ⎥⎦ where AV is the desired voltage gain in dB. RIN+ should be equal to RIN- and RFB+ should be equal to RFB-. The Class G output stage has a fixed gain of 4V/V (12dB). Any gain or attenuation set by the external input stage resistors will add to or subtract from this fixed gain. See Figure 3. MAX9730 EFFICIENCY vs. CLASS AB MAX9730 fig02 100 90 80 EFFICIENCY (%) MAX9730 2.4W, Single-Supply, Class G Power Amplifier 70 RFB+ MAX9730 CIN- 60 RIN+ IN+ 50 IN- 40 30 CINTRADITIONAL CLASS AB 20 MAX9730 FB+ + - RINRFB- 10 FB- 0 0 0.5 1.0 1.5 2.0 OUTPUT POWER (W) Figure 2. MAX9730 Efficiency vs. Class AB Efficiency vs. Class D Efficiency 8 Figure 3. Gain Setting _______________________________________________________________________________________ CLASS G OUTPUT STAGE 2.4W, Single-Supply, Class G Power Amplifier RFB + RFB − = RIN+ RIN− and CIN+ = CIN− Component Selection Input-Coupling Capacitor The AC-coupling capacitors (CIN_) and input resistors (RIN_) form highpass filters that remove any DC bias from an input signal (see the Typical Application Circuit/Functional Diagram). CIN_ blocks DC voltages from the amplifier. The -3dB point of the highpass filter, assuming zero source impedance due to the input signal source, is given by: Hold Capacitor (C2) The output capacitor value and ESR directly affect the ripple at PVSS. Increasing C2 reduces output ripple. Likewise, decreasing the ESR of C2 reduces both ripple and output resistance. A 10µF capacitor is recommended. Charge-Pump Frequency Set Resistor (RFS) The charge pump operates in two modes. When the charge pump is loaded below 100mA, it operates in a slow mode where the oscillation frequency is reduced to 1/4 of its normal operating frequency. Once loaded, the charge-pump oscillation frequency returns to normal operation. In applications where the design may be sensitive to the operating charge-pump oscillation frequency, the value of the external resistor RFS can be changed to adjust the charge-pump oscillation frequency (see Figure 4). 1 (Hz) 2π × RIN _ × CIN _ Charge-Pump Capacitor Selection Use capacitors with an ESR less than 50mΩ 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 CHARGE-PUMP OSCILLATION FREQUENCY vs. RFS 600 ILOAD > 100mA 550 MAX9730 fig04 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 low-voltage coefficient dielectrics. Aluminum electrolytic, tantalum, or film dielectric capacitors are good choices for AC-coupling capacitors. Capacitors with high-voltage coefficients, such as ceramics (non-C0G dielectrics), can result in increased distortion at low frequencies. CHARGE-PUMP OSCILLATION FREQUENCY (kHz) f−3dB = to provide sufficient current drive. Increasing the value of 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. A 4.7µF capacitor is recommended. 500 450 400 350 300 250 200 50 75 100 125 150 RFS (kΩ) Figure 4. Charge-Pump Oscillation Frequency vs. RFS _______________________________________________________________________________________ 9 MAX9730 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: MAX9730 2.4W, Single-Supply, Class G Power Amplifier Thermal Considerations The copper polygon to which the exposed pad is attached should have multiple vias to the opposite side of the PCB, where they connect to GND. Make this polygon as large as possible within the system’s constraints. Class G amplifiers provide much better efficiency and thermal performance than a comparable Class AB amplifier. However, the system’s thermal performance must be considered with realistic expectations and include consideration of many parameters. This section examines Class G amplifiers using general examples to illustrate good design practices. 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, go to the Maxim website at www.maximic.com/ucsp for the application note, UCSP—A WaferLevel Chip-Scale Package. TQFN Considerations 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 become the primary heatsink for the Class G amplifier. Solder the exposed pad to a large copper polygon that is connected to the ground plane. Typical Application Circuit/Functional Diagram VDD SHDN CONTROL SIGNAL 0.1μF * 20kΩ 14, 22 (D1, D5) 4 (A3) 1 (B2) VCC SHDN CPVDD 12 (B4) FB+ MAX9730 CIN 1μF RIN10kΩ RFB+ 10kΩ 10 (B5) IN+ + 9 (A5) INCIN 1μF RIN10kΩ OUT+ 20 (D2) CLASS G OUTPUT STAGE - OUT- 16 (D4) RFB10kΩ GND 18 (D3) ( ) WLP PACKAGE FS 13 (C5) CHARGE PUMP 7 (A4) FBCPGND 27 (A1) C1P C1N 26 (B1) PVSS 3 (A2) 24 (C1) C1 4.7μF RFS 100kΩ SVSS 15, 21 (C2, C4) C2 10μF DEVICE SHOWN WITH AV = 12dB *SYSTEM-LEVEL REQUIREMENT TYPICALLY 10μF 10 ______________________________________________________________________________________ 2.4W, Single-Supply, Class G Power Amplifier TOP VIEW (BUMP SIDE DOWN) N.C. CPGND C1N N.C. PVSS N.C. VCC 27 26 25 24 23 22 + 28 TOP VIEW MAX9730 SHDN 1 21 SVSS N.C. 2 20 OUT+ C1P 3 19 N.C. CPVDD 4 18 GND N.C. 5 17 N.C. N.C. 6 16 OUT- 15 SVSS 8 9 10 11 12 13 14 IN- IN+ N.C. FB+ FS VCC 7 EP* N.C. FB- MAX9730 1 2 3 4 5 CPGND C1P CPVDD FB- IN- C1N SHDN FB+ IN+ PVSS SVSS SVSS FS VCC OUT+ OUT- VCC A B C D GND WLP THIN QFN *EXPOSED PAD. Package Information Chip Information PROCESS: BiCMOS For the latest package outline information and land patterns, 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 PACKAGE CODE DOCUMENT NO. 20 WLP W202A2+1 21-0059 28 TQFN T2844-1 21-0139 ______________________________________________________________________________________ 11 MAX9730 Pin Configurations MAX9730 2.4W, Single-Supply, Class G Power Amplifier Revision History REVISION NUMBER REVISION DATE 0 1/07 Initial release 1 11/07 Include tape and reel note, edit Absolute Maximum Ratings, update TQFN package outline 2 12/07 Update Electrical Characteristics table 3 2/08 Changed UCSP to WLP throughout data sheet including new WLP package outline, added new TOCs 8 and 19 4 5/08 Updated Typcial Application Circuit and fixed various errors 1–6, 10 5 3/10 Removed erroneous bullet in the Features section and corrected errors in the Absolute Maximum Ratings section and the Electrical Characteristics table 1, 2, 3 DESCRIPTION PAGES CHANGED — 1, 2,12, 13 3 1, 2, 4, 6, 10, 11, 14 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. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.