19-5912; Rev 0; 6/11 EVALUATION KIT AVAILABLE MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers General Description The MAX98309/MAX98310 mono 1.4W class AB audio amplifiers offer low quiescent current while maintaining excellent SNR and low 0.008% THD+N. These ICs feature excellent 90dB PSRR and state of the art click-andpop suppression. The ICs are offered with an internally fixed 0dB, 3dB, 6dB, and 9dB gain (MAX98310) or an externally set gain (MAX98309) through external resistors. The MAX98309 feature a 10ms or 100ms pin-selectable turn-on time, while the MAX98310 has a preset 5ms turnon time. The MAX98309/MAX98310 are available in a (1.0mm x 1.0mm) 9-bump, 0.3mm pitch WLP, and are specified over the extended -40NC to +85NC temperature range. Applications Cell Phones/Smartphones Digital Cameras GPS Portable Media Players e-Readers Tablets Benefits and Features S Enhances System Performance Differential Input Improves Noise Immunity Industry-Leading Click-and-Pop Suppression High 90dB PSRR (fIN = 217Hz) S Smaller Solution Size 1mm x 1mm WLP Footprint S Extends Battery Life Low Quiescent Current S Delivers Robust System Design Thermal Overload Protection Short-Circuit Protection S 1.2mA Supply Current (VDD = 3.7V) S 750mW into 8I (VDD = 3.7V) S 2.5V to 5.5V Supply Operation S Pin-Selectable, Internally-Fixed Gain (MAX98310) S 1.8V Logic-Compatible SHDN Input 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/MAX98309.related. Simplified Block Diagram 2.5V TO 5.5V RF 2.5V TO 5.5V 0.1F 0.1F 1F 1F BIAS VDD BIAS VDD BIAS BIAS CIN RIN CIN RIN TON RF MAX98309 OUT+ INBIAS IN+ OUTSHDN CIN CIN MAX98310 VDD IN- IN+ RIN RIN OUT+ BIAS OUTGND GND RF GAIN RF SHDN GND 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. MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers ABSOLUTE MAXIMUM RATINGS VDD to GND................................................................ -0.3V to 6V SHDN to GND............................................................ -0.3V to 6V All Other Pins to GND................................-0.3V to (VDD + 0.3V) Continuous Current VDD, GND, OUT_........................................................ Q750mA IN_, SHDN, BIAS, GAIN, TON.......................................... Q20mA OUT_ Short Circuit to GND or VDD Duration.............Continuous OUT+ to OUT- Short Circuit Duration........................Continuous Continuous Power Dissipation (TA = +70NC) WLP (derate 11.9mW/NC above +70NC)......................848mW Junction Temperature......................................................+150NC Operating Temperature Range........................... -40NC to +85NC Storage Temperature Range............................. -65NC to +150NC Soldering Temperature (reflow).......................................+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) WLP Junction-to-Ambient Thermal Resistance (BJA)......... 94C/W Junction-to-Case Thermal Resistance (BJC)................41C/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 (VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = VDD (0dB), CBIAS = 0.1F, CIN = 0.47F, no load: RIN = RF = 10kI (MAX98309), TA = TMIN to TMAX. Typical values are at TA = +25C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL Supply Voltage Range VDD Undervoltage Lockout UVLO Quiescent Supply Current IVDD Shutdown Supply Current IVDD_SD Turn-On Time tON Gain AV CONDITIONS Guaranteed by PSRR test MIN VDD falling SHDN = VDD 1.8 MAX UNITS 5.5 V 2.3 V VDD = 3.7V 1.2 VDD = 5V 1.9 1.8 2 3 10 22.8 VSHDN = 0V, TA = +25NC MAX98309 shutdown to TON = GND full operation TON = VDD 100 MAX98310 shutdown to full operation 5.7 11.5 MAX98310 -0.25 0 +0.25 GAIN = GND 2.75 3 3.25 GAIN = unconnected 5.75 6 6.25 GAIN = BIAS 8.75 9 9.25 GAIN = VDD 0.80 x VDD MAX98310 mA FA ms GAIN = VDD 0.05 x VDD GAIN = GND Gain Selection Threshold TYP 2.5 GAIN = unconnected 0.16 x VDD 0.24 x VDD GAIN = BIAS 0.35 x VDD 0.69 x VDD dB V Maxim Integrated Products 2 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers ELECTRICAL CHARACTERISTICS (continued) (VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = VDD (0dB), CBIAS = 0.1F, CIN = 0.47F, no load: RIN = RF = 10kI (MAX98309), TA = TMIN to TMAX. Typical values are at TA = +25C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN RINDIFF Input Bias Current IINBIAS Shutdown Input Bias Current IINBIAS_ Output Offset Voltage Click-and-Pop Level SHDN MAX98310 38.2 GAIN = 3dB 31.7 GAIN = 6dB 25.5 MAX98309/MAX98310, SHDN = VDD SHDN = GND, IN_ = VDD or IN_ = GND TA = +25NC (Note 3) KCP RL = 8I, 32 samples per second, A-weighted, TA = +25NC (Notes 3, 4) Common-Mode Bias Voltage VBIAS Voltage at BIAS Input Common-Mode Voltage Range VCM Inferred from CMRR test Common-Mode Rejection Ratio GAIN = 0dB VOS CMRR MAX98310/MAX98310 -5 Q0.2 Into shutdown -66 Out of shutdown -66 0.475 x VDD VRIPPLE = 200mVP-P (Note 3) VDD = 3.7V, 1% THD+N VDD = 3.7V, 10% THD+N Output Power POUT VDD = 5V, 1% THD+N (Note 5) VDD = 5V, 10% THD+N (Note 5) 0.5 x VDD 0.5 Guaranteed over input commonmode voltage range DC 2.5V to 5.5V PSRR UNITS kI Q1 FA +5 FA Q1 mV dBV -50 0.525 x VDD V VDD 0.6 V -76 dB fIN = 1kHz, RL = 8I + 33FH Power-Supply Rejection Ratio MAX 1000 MAX98309, SHDN = VDD Differential Input Resistance TYP -62 73 93 fIN = 217Hz 90 fIN = 1kHz 90 fIN = 10kHz 72 RL = 8I + 68FH 0.750 RL = 4I + 33FH 1.2 RL = 8I + 68FH 0.9 RL = 4I + 33FH 1.5 RL = 8I + 68FH 1.4 RL = 4I + 33FH, thermally limited 2.1 RL = 8I + 68FH 1.7 RL = 4I + 33FH, thermally limited 2.7 dB W Maxim Integrated Products 3 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers ELECTRICAL CHARACTERISTICS (continued) (VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = VDD (0dB), CBIAS = 0.1F, CIN = 0.47F, no load: RIN = RF = 10kI (MAX98309), TA = TMIN to TMAX. Typical values are at TA = +25C, unless otherwise noted.) (Note 2) PARAMETER Total Harmonic Distortion Plus Noise SYMBOL THD+N CONDITIONS fIN = 1kHz, BW = 22Hz to 22kHz fIN = 6kHz, BW = 22Hz to 22kHz Signal-to-Noise Ratio SNR Output Noise Voltage VN MIN RL = 8I + 68FH, POUT = 375mW RL = 4I + 33FH, POUT = 750mW TYP MAX UNITS 0.008 0.06 RL = 8I + 68FH, POUT = 375mW 0.02 % 0.01 A-weighted, VDD = 5V, POUT = 1.4W, RL = 8I + 33FH 110 dB 9 FV 2 A Thermal-Protection Threshold +160 NC Thermal-Protection Hysteresis 15 NC 500 pF A-weighted (Note 3) Overcurrent Protection Threshold Maximum Capacitive Load Drive CL Bridge-tied load capacitance LOGIC INPUT (SHDN, TON) (MAX98309) Input Logic-High VIH 1.8V logic compliant 1.4 V Input Logic-Low VIL 1.8V logic compliant 0.4 V Input Leakage Current High IIH TA = +25NC 1 FA Input Leakage Current Low IIL TA = +25NC 1 FA Note Note Note Note 2: 3: 4: 5: All specifications are 100% tested at TA = +25C; temperature limits are guaranteed by design. Inputs AC-coupled to GND. Mode transitions controlled by SHDN. Thermally limited by package. Maxim Integrated Products 4 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Typical Operating Characteristics (VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1F, CIN = 1F, no load, unless otherwise noted.) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 0.1 0.01 1k 10k 0.01 0.001 0.001 100k 100 1k 10k 100k 10 100 1k 100k TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER POUT = 50mW fIN = 6kHz 1 fIN = 300Hz 0.1 0.01 0.01 MAX98309 toc06 VDD = 5V RL = 8I 10 THD+N (%) POUT = 500mW VDD = 4.2V RL = 4I 10 100 MAX98309 toc05 100 MAX98309 toc04 1 1 0.01 0.001 0.001 1k 10k 0 100k 500 1000 2000 1500 VDD = 3.7V RL = 4I 100 fIN = 6kHz 0.01 VDD = 3.7V RL = 8I 10 THD+N (%) 1 fIN = 300Hz 500 750 1000 1250 1500 1750 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER MAX98309 toc07 100 THD+N (%) 250 OUTPUT POWER (mW) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER 0.1 0 OUTPUT POWER (mW) FREQUENCY (Hz) 10 fIN = 1kHz 0.001 MAX98309 toc08 100 fIN = 6kHz fIN = 300Hz 0.1 fIN = 1kHz 10 10k FREQUENCY (Hz) THD+N (%) THD+N (%) 10 FREQUENCY (Hz) VDD = 3.7V RL = 8I 0.1 POUT = 800mW 0.1 FREQUENCY (kHz) 100 10 POUT = 200mW 1 POUT = 50mW 0.001 100 POUT = 1.2W 0.01 POUT = 50mW 10 1 0.1 VDD = 3.7V RL = 4I 10 THD+N (%) POUT = 300mW VDD = 5V RL = 8I 10 THD+N (%) 1 100 MAX98309 toc02 VDD = 4.2V RL = 4I THD+N (%) 100 MAX98309 toc01 10 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY MAX98309 toc03 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 1 fIN = 6kHz 0.1 fIN = 300Hz 0.01 fIN = 1kHz fIN = 1kHz 0.001 0 400 0.001 800 1200 OUTPUT POWER (mW) 1600 0 200 400 600 800 1000 OUTPUT POWER (mW) Maxim Integrated Products 5 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Typical Operating Characteristics (continued) (VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1F, CIN = 1F, no load, unless otherwise noted.) OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE 3 2 VOS (mV) 1 0 -1 -2 -2 -3 -3 -4 -4 -5 1 2 3 0 5 4 COMMON-MODE VOLTAGE (V) OUTPUT POWER vs. SUPPLY VOLTAGE fIN = 1kHz RL = 8I THD+N = 10% 1500 1000 THD+N = 10% 500 fIN = 1kHz RL = 4I 3000 OUTPUT POWER (mW) OUTPUT POWER (mW) 2000 3.5 2500 THD+N = 10% 2000 1500 THERMALLY LIMITED 1000 THD+N = 1% 500 0 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 2.5 SUPPLY VOLATGE (V) THERMALLY LIMITED 2.0 1.5 THD+N = 10% THD+N = 1% 1.0 4.0 4.5 5.0 5.5 OUTPUT POWER vs. LOAD VDD = 3.7V fIN = 1kHz ZLOAD = LOAD + 68H 1.6 1.4 OUTPUT POWER (mW) 2.5 3.5 1.8 MAX98309 toc13 VDD = 5V fIN = 1kHz ZLOAD = LOAD + 68H 3.0 SUPPLY VOLATGE (V) OUTPUT POWER vs. LOAD 3.0 OUTPUT POWER (W) 1.0 1.5 2.0 2.5 3.0 COMMON-MODE VOLTAGE (V) OUTPUT POWER vs. SUPPLY VOLTAGE 3500 MAX98309 toc11 2500 0.5 MAX98309 toc12 0 1.2 1.0 0.8 THD+N = 10% 0.6 0.4 0.5 MAX98309 toc14 VOS (mV) 0 -1 VDD = 3.7V RL = 8I 3 2 1 MAX98309 toc10 VDD = 5V RL = 8I 4 4 MAX98309 toc09 5 THD+N = 1% 0.2 0 0 1 10 100 LOAD RESISTANCE (I) 1k 1 10 100 1k LOAD RESISTANCE (I) Maxim Integrated Products 6 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Typical Operating Characteristics (continued) (VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1F, CIN = 1F, no load, unless otherwise noted.) POWER DISSIPATION vs. OUTPUT POWER RL = 8I 600 400 200 RL = 4I 500 400 300 RL = 8I 200 100 0 0 1000 1500 0 2000 300 600 900 1200 1500 0 -10 MAX98309 toc18 10 100 1k 10k -70 VDD = 3.7V 100k VDD = 5V 10 100 1k 10k FREQUENCY (Hz) CMRR vs. FREQUENCY (MAX98309) CMRR vs. FREQUENCY (MAX98310) -20 1000k -60 FREQUENCY (Hz) RL = 8I THD + N = 1% 100k 10k -40 -50 -80 -90 -100 -110 -120 VDD = 3.7V 100 1k RL = 8I VRIPPLE = 200mV -20 -30 PSRR (dB) VDD = 5V 0 AV = 0dB PSRR vs. FREQUENCY (MAX98310) 0 MAX98309 toc20 PSRR (dB) RL = 8I VRIPPLE = 200mV -10 AV = 3dB FREQUENCY (Hz) PSRR vs. FREQUENCY (MAX98309) 10 AV = 6dB OUTPUT POWER (mW) OUTPUT POWER (mW) 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 AV = 9dB MAX98309 toc19 500 0 VDD = 3.7V fIN = 1kHz POUT = POUTL + POUTR 12 11 10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 RL = 8I THD + N = 1% -10 -20 -30 100k MAX98309 toc21 800 600 GAIN (dB) RL = 4I MAX98309 toc16 700 1000 -30 -40 CMRR (dB) CMRR (dB) POWER DISSIPATION (mW) 1200 800 POWER DISSIPATION (mW) VDD = 5V fIN = 1kHz POUT = POUTL + POUTR MAX98309 toc15 1400 GAIN vs. FREQUENCY (MAX98310) MAX98309 toc17 POWER DISSIPATION vs. OUTPUT POWER VDD = 3.7V -50 -60 -70 -40 VDD = 3.7V -50 -60 -70 -80 VDD = 5V -80 VDD = 5V -90 -90 -100 -100 10 100 1k FREQUENCY (Hz) 10k 100k 10 100 1k 10k 100k FREQUENCY (Hz) Maxim Integrated Products 7 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Typical Operating Characteristics (continued) (VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1F, CIN = 1F, no load, unless otherwise noted.) TURN-ON TIME (MAX98309) 10ms TURN-ON TIME (MAX98309) 100ms MAX98309 toc22 TURN-ON TIME MAX98310 MAX98309 toc23 2ms/div MAX98309 toc24 20ms/div 1ms/div SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT vs. TEMPERATURE 2.0 1.5 1.0 1.5 VDD = 3.7V 1.0 0.5 0.5 0 0 3.5 4.0 4.5 5.0 5.5 -40 -15 10 35 60 SUPPLY VOLTAGE (V) TEMPERATURE (C) SHUTDOWN CURRENT vs. SUPPLY VOLTAGE SHUTDOWN CURRENT vs. TEMPERATURE MAX98309 toc27 9 8 7 6 5 4 3 2 10 85 MAX98309 toc28 3.0 9 SHUTDOWN CURRENT (A) 2.5 SHUTDOWN CURRENT (A) MAX98309 toc26 VDD = 5V 2.0 SUPPLY CURRENT (mA) 2.5 SUPPLY CURRENT (mA) 2.5 MAX98309 toc25 3.0 8 VDD = 5V 7 6 5 4 VDD = 3.7V 3 2 1 1 0 0 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 -40 -15 10 35 60 85 TEMPERATURE (C) Maxim Integrated Products 8 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Pin Configurations TOP VIEW (BUMP SIDE DOWN) TOP VIEW (BUMP SIDE DOWN) MAX98309 1 2 3 + MAX98310 1 2 3 + A OUT+ SHDN IN- A OUT+ SHDN IN- B GND TON VDD B GND GAIN VDD C OUT- BIAS IN+ C OUT- BIAS IN+ WLP WLP Pin Descriptions PIN NAME FUNCTION MAX98309 MAX98310 A1 A1 OUT+ Amplifier Positive Output A2 A2 SHDN Active-Low Shutdown Input. Connect to GND to place the IC into shutdown. Connect to VDD for normal operation. A3 A3 IN- B1 B1 GND Ground B2 -- TON Turn-On Time Selection. Connect TON to GND for a 10ms turn-on time. Connect TON to VDD for a 100ms turn on time. -- B2 GAIN Gain Select Input. See Table 1 for gain settings. Inverting Audio Input B3 B3 VDD Power Supply Input. Connect a 1FF capacitor from VDD to GND. C1 C1 OUT- Amplifier Negative Output C2 C2 BIAS Common-Mode DC Bias Bypass. Connect a 0.1FF (min) capacitor to GND. C3 C3 IN+ Noninverting Audio Input Maxim Integrated Products 9 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Detailed Description The MAX98309/MAX98310 mono 1.4W Class AB audio amplifiers offer low quiescent current while maintaining excellent SNR and low 0.008% THD+N. Both ICs feature excellent 90dB PSRR and state-of-the-art click-and-pop suppression. Applications Information BTL Amplifier The ICs are offered with an internally fixed 0dB, 3dB, 6dB, and 9dB gain (MAX98310) or an externally set gain (MAX98309) through external resistors. The ICs are designed to drive a load differentially, a configuration referred to as bridge-tied load, or BTL. The BTL configuration (Figure 1) offers advantages over the single-ended configuration, where one side of the load is connected to ground. Driving the load differentially doubles the output voltage compared to a single-ended amplifier under similar conditions. The MAX98309 features a 10ms or 100ms pin-selectable turn-on time, while the MAX98310 has a preset 5ms turnon time. Substituting 2 x VOUT(P-P) for VOUT(P-P) into the following equations yields four times the output power due to doubling of the output voltage: Bias The ICs operate from a single 2.5V to 5.5V power supply and feature an internally generated common-mode bias voltage of VDD/2 reference to ground. BIAS provides both click-and-pop suppression and sets the DC bias level for the audio outputs. Choose the value of the bypass capacitor as described in the BIAS Capacitor section. Do not connect external loads to BIAS as this can affect the overall performance. Turn-On Time The MAX98309 external gain amplifier features a selectable turn-on time for optimized click-and-pop performance. Connect TON to GND for a 10ms turn-on time. Connect TON to VDD for a 100ms turn-on time. The MAX98310 has a preset 5ms turn-on time. Shutdown Mode The ICs feature a 1.8FA low-power shutdown mode that reduces quiescent current consumption. When the active-low shutdown mode is entered, the ICs' internal bias circuitry is disabled, the amplifier outputs go high impedance, and BIAS is driven to GND. Click-and-Pop Suppression The ICs feature Maxim's industry-leading click-andpop suppression circuitry. During startup, the amplifier common-mode bias voltage ramps to the DC bias point. When entering shutdown, the amplifier outputs are high impedance between both outputs. This scheme minimizes the energy present in the audio band. VRMS = VOUT (P -P) 2 2 VRMS 2 POUT = RL Because the differential outputs are biased at midsupply, there is no net DC voltage across the load. This eliminates the need for DC-blocking capacitors required for single-ended amplifiers. These capacitors can be large, expensive, consume board space, and degrade lowfrequency performance. Power Dissipation and Heatsinking Under normal operating conditions, the ICs dissipate a significant amount of power. The maximum power dissipation is given in the Absolute Maximum Ratings or can be calculated by the following equation: PD(MAX) = TJ(MAX) - TA JA where TJ(MAX) is +150NC, TA is the ambient temperature, and BJA is the reciprocal of the derating factor in C/W as specified in the Absolute Maximum Ratings. +1 VOUT(P-P) 2 x VOUT(P-P) -1 VOUT(P-P) Figure 1. BTL Configuration Maxim Integrated Products 10 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers The increase in power delivered by the BTL configuration directly results in an increase in internal power dissipation over the single-ended configuration. The maximum internal power dissipation for a given VDD and load is given by the following equation: PD(MAX) = 2VDD 2 2R L If the internal power dissipation for a given application exceeds the maximum allowed for a given package, reduce power dissipation by increasing the ground plane heatsinking capability and the size of the traces to the device. See the Layout and Grounding section. Other methods for reducing power dissipation are to reduce VDD, increase load impedance, decrease ambient temperature, reduce gain, or reduce input signal. Thermal-overload protection limits total power dissipation in the MAX98309/MAX98310. When the junction temperature exceeds +160NC, the thermal protection circuitry disables the amplifier. Operation returns to normal once the die cools by 15NC. Amplifier Gain Fixed Differential Gain (MAX98310) The MAX98310 features four internally fixed differential gain options selectable by GAIN (Table 1). This simplifies design, decreases required application footprint size, and eliminates external gain-setting resistors. External Differential Gain (MAX98309) The MAX98309 features an external gain option. Resistors RF and RIN. See the Simplified Block Diagram and set the gain of the amplifier as follows: AV = RF RIN Input Filter The fully differential amplifier inputs can be biased at voltages other than midsupply. The common-mode feedback circuit adjusts for input bias, ensuring the outputs are still biased at midsupply. Input capacitors are not required as long as the input voltage is within the specified common-mode range listed in the Electrical Characteristics table. If input capacitors are used, input capacitor CIN, in conjunction with the input resistor RIN, 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 2RIN CIN Setting f-3dB too high affects the low-frequency response of the amplifier. Use capacitors with adequately low voltage coefficients, such as X7R ceramic capacitors with a high voltage rating. Capacitors with higher voltage coefficients result in increased distortion at low frequencies. BIAS Capacitor BIAS is the output of the internally generated VDD/2 bias voltage. The BIAS bypass capacitor, CBIAS, improves PSRR and THD+N by reducing power supply and other noise sources at the common-mode bias node, and also generates the clickless/popless startup DC bias waveform for the speaker amplifiers. Bypass BIAS with a 0.1FF capacitor to GND. Larger values of CBIAS (up to 1FF) improve PSRR. Supply Bypassing where AV is the desired voltage gain. Hence, an RIN of 10kI and an RF of 20kI yields a gain of 2V/V or 6dB. RF can be either fixed or variable, allowing the use of a digitally controlled potentiometer to alter the gain under software control. Table 1. Fixed Differential Gain GAIN CONNECTION GAIN (dB) VDD 0 GND 3 Unconnected 6 BIAS 9 Proper power-supply bypassing ensures low-noise, lowdistortion performance. Connect a 1FF ceramic capacitor from VDD to GND. Add additional bulk capacitance as required by the application. Locate the bypass capacitor as close as possible to the device. Layout and Grounding Good PCB layout is essential for optimizing performance. Use large traces for the power-supply inputs and amplifier outputs to minimize losses due to parasitic trace resistance and route heat away from the device. Good grounding improves audio performance, and prevents any digital switching noise from coupling into the audio signal. Maxim Integrated Products 11 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Ordering Information PART TEMP RANGE GAIN PIN-PACKAGE TOP MARK MAX98309EWL+ -40NC to +85NC External 9 WLP +AIY MAX98310EWL+ -40NC to +85NC Fixed 9 WLP +AIZ +Denotes a lead(Pb)-free/RoHS-compliant package. Maxim Integrated Products 12 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers 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 PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 9 WLP (0.3mm pitch) W91D1+1 21-0486 Refer to Application Note 1891 COMMON DIMENSIONS PIN 1 INDICATOR MARKING E A3 1 A2 A 0.03 A2 0.48 REF 0.025 BASIC 0.21 A See Note 7 SIDE VIEW E 0.03 0.60 BASIC D1 S TOP VIEW 0.05 0.16 b 0.05 S D 0.64 A3 A1 AAAA A A1 E1 0.60 BASIC e 0.30 BASIC SD 0.00 BASIC SE 0.00 BASIC D PKG. CODE MIN MAX MIN MAX W91D1+1 0.95 0.98 0.95 0.98 DEPOPULATED BUMPS NONE E1 e SE B SD C D1 B A 1 2 3 b NOTES: 1. Terminal pitch is defined by terminal center to center value. 2. Outer dimension is defined by center lines between scribe lines. 3. All dimensions in millimeter. 4. Marking shown is for package orientation reference only. 5. Tolerance is 0.02 unless specified otherwise. 6. All dimensions apply to PbFree (+) package codes only. 7. Front - side finish can be either Black or Clear. A BOTTOM VIEW TITLE -DRAWING NOT TO SCALE- APPROVAL PACKAGE OUTLINE 9 BUMPS, WLP PKG. 0.3mm PITCH DOCUMENT CONTROL NO. 21-0486 REV. B 1 1 Maxim Integrated Products 13 MAX98309/MAX98310 Mono 1.4W Class AB Audio Amplifiers Revision History REVISION NUMBER REVISION DATE 0 6/11 DESCRIPTION Initial release PAGES CHANGED -- 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 (c) 2011 Maxim Integrated Products 14 Maxim is a registered trademark of Maxim Integrated Products, Inc.