MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics General Description The MAX13330/MAX13331 stereo headphone amplifiers are designed for automotive applications requiring output short-circuit and ESD protection to battery/ground with diagnostics. These devices use Maxim's unique DirectDrive(R) architecture to produce a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, saving board space and component height. The gain of the amplifier is set internally (-1.5V/V) on the MAX13330 or adjusted externally with resistors on the MAX13331. The MAX13330/MAX13331 deliver 120mW per channel into a 16 load or 135mW into a 32 load and have a low 0.01% THD+N. Low output impedance and the efficient integrated charge pump allows the device to drive loads as low as 8, enabling the use of small loudspeakers. An 80dB at 217Hz PSRR allows these devices to operate from noisy digital supplies without an additional linear regulator. These devices include 15kV Human Body Model ESD protection and shortcircuit protection up to +45V at the headphone outputs. Comprehensive click-and-pop circuitry suppresses audible clicks and pops on startup and shutdown. A low-power shutdown mode reduces the supply current to 3A (typ). The MAX13330/MAX13331 are specified from -40C to +105C AEC-Q100 Level 2 automotive temperature range and are available in a 16-pin QSOP package. Applications Features o 4V to 5.5V Single-Supply Operation o 2MHz Charge Pump Prevents AM Radio Interference o Ground-Referenced Outputs Eliminate Bulky DCBlocking Capacitors o Short-to-Ground and Battery (VBAT up to +45V) Output Protection, Load Dump Protection o Short-Circuit Diagnostic Output o Adjustable Gain (MAX13331) or Fixed -1.5V/V Gain (MAX13330) o 125mW per Channel into 32 at 0.01% THD+N o Integrated Click-and-Pop Suppression o High PSRR Eliminates LDO o No Degradation of Low-Frequency Response Due to Output Capacitors o 15kV Human Body Model ESD Protection for Output Pins Ordering Information PART GAIN MAX13330GEE/V+T -1.5V/V DirectDrive is a registered trademark of Maxim Integrated Products, Inc. PINPACKAGE -40C to +105C 16 QSOP Externally -40C to +105C 16 QSOP Set MAX13331GEE/V+T Automotive Entertainment Systems Automotive Rear Seat Entertainment Systems TEMP RANGE /V denotes an automotive qualified part. +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel. Typical Application Circuits appear at end of data sheet. Simplified Block Diagram Pin Configuration INL 1 SGND 2 + 16 OUTL 15 PGND 14 VSS 13 OUTR MAX13330 SHDN RIGHT-CHANNEL AUDIO IN CLICK-AND-POP SUPPRESSION OUTPUT PROTECTION & DIAGNOSTICS LEFT-CHANNEL AUDIO IN DIAGNOSTICS OUTPUT INR 3 SGND 4 MAX13330 MAX13331 VDD 5 12 DIAG SHDN 6 11 CPVSS CPVDD 7 10 C1N C1P 8 9 PGND QSOP For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maximintegrated.com. 19-4341; Rev 4; 11/15 MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics ABSOLUTE MAXIMUM RATINGS VDD, CPVDD to SGND..............................................-0.3V to +6V VSS, CPVSS to SGND ...............................................+0.3V to -6V VDD, CPVDD..........................................................-0.3V to +0.3V VSS, CPVSS ...........................................................-0.3V to +0.3V SHDN, DIAG to SGND................................-0.3V to (VDD + 0.3V) OUT_ to PGND.......................................(VCPVSS - 0.3V) to +45V IN_ to SGND (MAX13330)................(VSS - 0.3V) to (VDD + 0.3V) IN_ to SGND (MAX13331) ..........................-0.3V to (VDD + 0.3V) C1P to PGND........................................-0.3V to (VCPVDD + 0.3V) C1N to PGND..............................................(VSS - 0.3V) to +0.3V Output Short-Circuit Duration.....................................Continuous Continuous Power Dissipation (TA = +70C) QSOP (derate 9.6mW/C above +70C))..................771.5mW Operating Temperature Range .........................-40C to +105C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C Soldering Temperature (reflow) .......................................+260C 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) QSOP Junction-to-Ambient Thermal Resistance (JA) ......103.7C/W Junction-to-Case Thermal Resistance (JC) ................37C/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 = VCPVDD = +5V, VSGND = VPGND = 0V, SHDN = VDD, C1 = C2 = 1F, RL = , resistive load referenced to ground, for MAX13330 gain = -1.5V/V (internally set), for MAX13331 gain = -1.5V/V (RIN = 30k, RFB = 45k), TA = TJ = -40C to +105C, unless otherwise noted. Typical values are at TA = +25C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS GENERAL Amplifier Supply Voltage Range VDD 4.0 5.5 V Charge-Pump Supply Voltage Range VCPVDD 4.0 5.5 V Charge-Pump Output Voltage VCPVSS Quiescent Supply Current IDD Shutdown Supply Current I SHDN SHDN Input-Logic High VIH SHDN Input-Logic Low VIL RL = V 10 mA 10 2 SHDN Input Leakage Current SHDN to Full Operation Time -VDD V -1 t SON A 0.8 V +1 A 100 s DIAGNOSTICS 0.02 x VDD No fault Diagnostic Output Voltage 2 VDIAG RDIAG = , TA = +25C OUTR short to SGND 0.22 x VDD 0.25 x VDD 0.28 x VDD OUTL short to SGND 0.47 x VDD 0.50 x VDD 0.53 x VDD OUTR short to VBAT 0.72 x VDD 0.75 x VDD 0.78 x VDD OUTL short to VBAT 0.97 x VDD V Maxim Integrated MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics ELECTRICAL CHARACTERISTICS (continued) (VDD = VCPVDD = +5V, VSGND = VPGND = 0V, SHDN = VDD, C1 = C2 = 1F, RL = , resistive load referenced to ground, for MAX13330 gain = -1.5V/V (internally set), for MAX13331 gain = -1.5V/V (RIN = 30k, RFB = 45k), TA = TJ = -40C to +105C, unless otherwise noted. Typical values are at TA = +25C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Short-to-SGND Threshold 130 mA Short-to-VBAT Threshold 130 mA AMPLIFIERS Voltage Gain AV Gain Matching MAX13330 -1.48 MAX13330 Input Offset Voltage 1 Input Bias Current Input Impedance VIN_ = 0V RIN MAX13330 20 THD+N = 1%; VDD = VCPVDD = 5V; f IN = 1kHz Output Voltage VOUT_ RL = 1k RL = 8 75 RL = 16 120 RL = 32 135 Signal-to-Noise Ratio SNR Noise Vn Slew Rate SR Maximum Capacitive Load CL Click-and-Pop Level Charge-Pump Oscillator Frequency Crosstalk KCP dB mW 2 VRMS k RL = 16, P OUT = 100mW, f = 1kHz 0.03 % RL = 32, P OUT = 125mW, f = 1kHz 0.01 % RL = 32, POUT = 135mW, f = 22Hz to 22kHz 100 dB 6 VRMS 0.3 V/s f = 22Hz to 22kHz bandwidth; inputs AC-coupled to grounded No sustained oscillation Peak voltage, TA = +25C, A-weighted, 32 samples per second; Inputs ACcoupled to ground 3000 Into shutdown -80 Out of shutdown -60 pF dB 1.9 f OSC RL = 32, VIN = 200mVP-P, f = 10kHz Thermal-Shutdown Temperature Thermal-Shutdown Hysteresis ESD Protection % 14 Output Impedance in Shutdown THD+N mV nA -80 POUT_ 6 k f =1kHz, VRIPPLE = 100mVP-P Output Power Per Channel V/V 50 -86 PSRR -1.52 30 DC, VDD = 4.0V to 5.5V, input referred Power-Supply Rejection Ratio Total Harmonic Distortion Plus Noise -1.5 0.2 Human Body Model (OUTR and OUTL) 2.2 2.5 MHz -75 dB +155 C 10 C 15 kV Note 2: All devices are 100% tested at TA = +25C; specifications over temperature limits are guaranteed by design and QA sampling. Maxim Integrated 3 MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Typical Operating Characteristics (VDD = VCPVDD = 5V, VSGND = VPGND = 0V, C1 = C2 = 1F, RL = , gain = -1.5V/V, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.) VDD = 4V RL = 8 VDD = 5V RL = 8 POUT = 25mW 0.1 POUT = 60mW 0.01 0.001 0.01 0.1 1 10 100 0.01 0.1 1 10 0.01 100 0.1 10 FREQUENCY (kHz) FREQUENCY (kHz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY POUT = 25mW 0.01 POUT = 125mW 0.001 0.001 1 10 POUT = 50mW POUT = 70mW 0.001 0.1 MAX13330/31 toc06 MAX13330/31 toc05 VDD = 5V RL = 32 0.01 POUT = 100mW 100 0.01 0.1 1 10 0.01 100 0.1 1 10 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 VDD = 5V RL = 8 VDD = 4V RL = 16 1 fIN = 10kHz fIN = 10kHz fIN = 1kHz 0.1 fIN = 1kHz THD+N (%) 1 THD+N (%) 1 10 100 MAX13330/31 toc09 VDD = 4V RL = 8 MAX13330/31 toc08 10 MAX13330/31 toc07 10 100 0.1 THD+N (%) THD+N (%) 1 0.1 POUT = 50mW 0.01 VDD = 4V RL = 32 THD+N (%) 0.1 1 MAX13330/31 toc04 VDD = 5V RL = 16 THD+N (%) 1 FREQUENCY (kHz) 1 0.01 POUT = 75mW 0.001 0.001 0.01 POUT = 25mW THD+N (%) THD+N (%) POUT = 45mW 0.01 VDD = 4V RL = 16 POUT = 25mW 0.1 THD+N (%) 0.1 1 MAX13330/31 toc02 1 MAX13330/31 toc01 1 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY MAX13330/31 toc03 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY fIN = 10kHz fIN = 1kHz 0.1 0.1 0.01 fIN = 100Hz fIN = 100Hz 0.01 0.001 0.01 0 25 50 OUTPUT POWER (mW) 4 fIN = 100Hz 75 0 25 50 75 OUTPUT POWER (mW) 100 125 0 25 50 75 100 125 OUTPUT POWER (mW) Maxim Integrated MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Typical Operating Characteristics (continued) (VDD = VCPVDD = 5V, VSGND = VPGND = 0V, C1 = C2 = 1F, RL = , gain = -1.5V/V, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER 1 fIN = 1kHz 0.1 0.01 fIN = 100Hz 0.001 50 75 100 125 150 0 175 25 50 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 125 0 VOUT_ = 2VRMS VOUT_ = 1VRMS fIN = 1kHz 1% THD+N 160 140 120 RL = 8 4.25 4.50 4.75 5.00 5.25 80 60 1% THD+N VDD = 4V 10 0 5.50 RL = 16 500 400 300 RL = 32 1200 VDD = 5V fIN = 1kHz 1000 POWER DISSIPATION (mW) VDD = 4V fIN = 1kHz 700 POWER DISSIPATION (mW) 100 100 1000 POWER DISSIPATION vs. OUTPUT POWER PER CHANNEL MAX13330/31 toc16 800 200 10% THD+N VDD = 4V LOAD RESISTANCE () POWER DISSIPATION vs. OUTPUT POWER PER CHANNEL RL = 8 RL = 16 800 600 400 RL = 32 200 100 0 0 0 20 40 60 80 100 OUTPUT POWER PER CHANNEL (mW) Maxim Integrated 1% THD+N VDD = 5V 120 SUPPLY VOLTAGE (V) RL = 8 175 0 4.00 FREQUENCY (kHz) 600 140 20 0 100 10 150 10% THD+N VDD = 5V 40 20 1 125 160 60 0.0001 100 fIN = 1kHz 180 RL = 16 80 75 OUTPUT POWER vs. LOAD RESISTANCE RL = 32 40 0.1 50 200 100 0.001 0.01 25 OUTPUT POWER (mW) 180 OUTPUT POWER (mW) MAX13330/31 toc13 VDD = 5V RL = 1k 0.01 100 OUTPUT POWER vs. SUPPLY VOLTAGE 1 0.1 75 OUTPUT POWER (mW) OUTPUT POWER (mW) OUTPUT POWER (mW) 25 fIN = 100Hz 0.001 MAX13330/31 toc14 0 fIN = 1kHz 0.1 0.01 fIN = 100Hz 0.001 fIN = 10kHz MAX13330/31 toc15 0.01 THD+N (%) 1 fIN = 10kHz MAX13330/31 toc17 fIN = 1kHz VDD = 5V RL = 32 THD+N (%) fIN = 10kHz VDD = 4V RL = 32 THD+N (%) THD+N (%) 1 10 MAX13330/31 toc11 VDD = 5V RL = 16 0.1 10 MAX13330/31 toc10 10 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER MAX13330/31 toc12 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER 120 0 20 40 60 80 100 120 140 160 180 OUTPUT POWER PER CHANNEL (mW) 5 MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Typical Operating Characteristics (continued) (VDD = VCPVDD = 5V, VSGND = VPGND = 0V, C1 = C2 = 1F, RL = , gain = -1.5V/V, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY VDD = 5V OUTR VDD = 5V OUTL -110 0.1 0.01 1 10 GAIN (dB) -70 RIGHT TO LEFT OUTL 3.3 3.2 -80 3.1 LEFT TO RIGHT MAX13330 VIN = 100mVP-P 3.0 0.1 0.01 100 1 10 0.01 100 0.1 1 OUTPUT FFT -40 -60 -80 -100 MAX13330/31 toc22 10 9 8 SUPPLY CURRENT (mA) MAX13330/31 toc21 RL = 32 -20 7 6 5 4 3 2 -120 100 1000 SUPPLY CURRENT vs. TEMPERATURE SUPPLY CURRENT vs. SUPPLY VOLTAGE 0 10 FREQUENCY (kHz) FREQUENCY (kHz) FREQUENCY (kHz) AMPLITUDE (dBV) MAX13330/31 toc20 OUTR -100 -120 12 10 8 6 4 2 1 -140 0 0 0 5 10 20 15 4.00 4.25 FREQUENCY (kHz) SHUTDOWN CURRENT vs. TEMPERATURE 3.0 2.5 2.0 1.5 1.0 4.75 5.00 5.25 5.50 -50 -25 0 25 50 75 100 SUPPLY VOLTAGE (V) TEMPERATURE (C) SHUTDOWN CURRENT vs. SUPPLY VOLTAGE EXITING SHUTDOWN TRANSIENT 125 MAX13330/31 toc26 MAX13330/31 toc25 3.5 4.50 5 SHUTDOWN CURRENT (A) MAX13330/31 toc24 4.0 SHUTDOWN CURRENT (A) 3.4 -60 -90 VRIPPLE = 100mVP-P RL = 32 MAX13330/31 toc19 VIN = 200mVP-P RL = 32 MAX13330/31 toc23 -100 3.5 SUPPLY CURRENT (mA) PSRR (dB) -80 -90 -50 CROSSTALK (dB) VDD = 4V OUTR VDD = 4V OUTL -70 -40 MAX13330/31 toc18 -50 -60 GAIN FLATNESS vs. FREQUENCY CROSSTALK vs. FREQUENCY -40 4 VSHDN 5V/div 3 VOUTL 1V/div 2 VOUTR 1V/div 1 0.5 0 0 -50 -25 0 25 50 75 TEMPERATURE (C) 6 100 125 4.00 4.25 4.50 4.75 5.00 5.25 5.50 200s/div SUPPLY VOLTAGE (V) Maxim Integrated MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Typical Operating Characteristics (continued) (VDD = VCPVDD = 5V, VSGND = VPGND = 0V, C1 = C2 = 1F, RL = , gain = -1.5V/V, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25C, unless otherwise noted.) ENTERING SHUTDOWN TRANSIENT POWER-UP/-DOWN TRANSIENT MAX13330/31 toc27 MAX13330/31 toc28 VSHDN 5V/div VSHDN 5V/div VOUTL 1V/div VOUTL 1V/div VOUTR 1V/div VOUTR 1V/div 200s/div 10ms/div Pin Description PIN NAME 1 INL 2, 4 SGND 3 INR Inverting Right-Channel Audio Input 5 VDD Amplifier Positive-Power Supply. Connect to positive supply. Bypass with a 1F capacitor to SGND as close to the pin as possible. 6 SHDN Active-Low Shutdown Input 7 CPVDD Charge-Pump Power Supply. Powers charge-pump inverter, charge-pump logic, and oscillator. Connect to positive supply. Bypass with a 1F capacitor to PGND as close to the pin as possible. 8 C1P 9, 15 PGND 10 C1N 11 CPVSS 12 DIAG Diagnostic Voltage Output 13 OUTR Right-Channel Output 14 VSS 16 OUTL Maxim Integrated FUNCTION Inverting Left-Channel Audio Input Amplifier Signal Ground. The noninverting inputs of the amplifiers are connected to the amplifier signal ground. Connect both to the signal ground plane. Flying-Capacitor Positive Terminal. Connect a 1F capacitor between C1P and C1N. Power Ground. Connect both to the power ground plane. Flying-Capacitor Negative Terminal. Connect a 1F capacitor between C1P and C1N. Charge-Pump Output. Connect to VSS and bypass with a 1F capacitor to PGND. Amplifier Negative Power Supply. Connect to CPVSS. Left-Channel Output 7 MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Detailed Description The MAX13330/MAX13331 headphone amplifiers feature Maxim's DirectDrive architecture, eliminating the large output-coupling capacitors required by conventional single-supply headphone amplifiers. The devices consists of two Class AB headphone amplifiers, undervoltage lockout (UVLO), low-power shutdown control, comprehensive click-and-pop suppression, output short-circuit/ESD protection and output short-circuit diagnostics. These devices can drive loads as low as 8, and deliver up to 120mW per channel into 16 and 135mW into 32. The MAX13330 features a fixed gain of -1.5V/V, and the MAX13331 features a programmable gain configured with external resistors. The headphone outputs feature 15kV Human Body Model ESD protection, and enhanced short-circuit protection to ground or battery (VBAT up to +45V). An integrated short-circuit diagnostic output provides the status of the MAX13330/ MAX13331 during operation as a fraction of the analog supply voltage. VDD VOUT VDD/2 GND CONVENTIONAL DRIVER-BIASING SCHEME VDD DirectDrive Conventional single-supply headphone amplifiers have their outputs biased about a nominal DC voltage (typically half the supply) for maximum dynamic range. Large coupling capacitors are needed to block this DC bias from the headphone. Without these capacitors, a significant amount of DC current flows to the headphone, resulting in unnecessary power dissipation and possible damage to both the headphone and the headphone amplifier. Maxim's DirectDrive architecture uses a charge pump to create an internal negative-supply voltage, allowing the MAX13330/MAX13331 outputs to be biased about SGND (Figure 1). With no DC component, there is no need for the large DC-blocking capacitors. Instead of two large (220F, typ) tantalum capacitors, the MAX13330/MAX13331 charge pump requires two small ceramic capacitors, conserving board space, reducing cost, and improving the frequency response of the headphone amplifier. See the Output Power vs. Load Resistance graph in the Typical Operating Characteristics for details of the possible capacitor sizes. There is a low DC voltage on the amplifier outputs due to amplifier offset. However, the output offset of the MAX13330 is typically 2.5mV which, when combined with a 32 load, results in less than 78A of DC current flow to the headphones. Previous attempts to eliminate the output-coupling capacitors involved biasing the headphone return (sleeve) to the DC-bias voltage of the headphone amplifiers. 8 VOUT GND VSS DirectDrive BIASING SCHEME Figure 1. Conventional Driver Output Waveform vs. MAX13330/ MAX13331 Output Waveform This method raises some issues: * The sleeve is typically grounded to the chassis. Using this biasing approach, the sleeve must be isolated from system ground, complicating product design. * During an ESD strike, the amplifier's ESD structures are the only path to system ground. Thus, the amplifier must be able to withstand the full ESD strike. * When using the headphone jack as a line out to other equipment, the bias voltage on the sleeve may conflict with the ground potential from other equipment, resulting in possible damage to the amplifiers. Maxim Integrated MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics f-3dB = 1 (Hz) 2 x RL x COUT where R L is the impedance of the headphone and COUT is the value of the DC-blocking capacitor. The highpass filter is required by conventional singleended, single power-supply headphone amplifiers to block the midrail DC-bias component of the audio signal from the headphones. The drawback to the filter is that it can attenuate low-frequency signals. Larger values of COUT reduce this effect but result in physically larger, more expensive capacitors. Figure 2 shows the relationship between the size of COUT and the resulting low-frequency attenuation. Note that the -3dB point for a 16 headphone with a 100F blocking capacitor is 100Hz, well within the normal audio band, resulting in low-frequency attenuation of the reproduced signal. LOW-FREQUENCY ROLLOFF (RL = 16) 2) The voltage coefficient of the DC-blocking capacitor contributes distortion to the reproduced audio signal as the capacitance value varies and the function of the voltage across the capacitor changes. The reactance of the capacitor dominates at frequencies below the -3dB point and the voltage coefficient appears as frequency-dependent distortion. Figure 3 shows the THD+N introduced by two different capacitor dielectric types. Note that below 100Hz, THD+N increases rapidly. The combination of low-frequency attenuation and frequency-dependent distortion compromises audio reproduction in portable audio equipment that emphasizes low-frequency effects such as in multimedia laptops, MP3, CD, and DVD players. By eliminating the DC-blocking capacitors through DirectDrive technology, these capacitor-related deficiencies are eliminated. ADDITIONAL THD+N DUE TO DC-BLOCKING CAPACITORS 10 1 THD+N (%) Low-Frequency Response In addition to the cost and size disadvantages of the DCblocking capacitors required by conventional headphone amplifiers, these capacitors limit the amplifier's low-frequency response and can distort the audio signal: 1) The impedance of the headphone load and the DCblocking capacitor form a highpass filter with the -3dB point set by: 0.1 TANTALUM 0.01 0.001 ALUM/ELEC 0 0.0001 -3 -6 ATTENUATION (dB) 10 DirectDrive -9 100 1k 10k 100k FREQUENCY (Hz) 330F -12 Figure 3. Distortion Contributed by DC-Blocking Capacitors 220F -15 100F -18 33F -21 -24 -27 -30 10 100 1k 10k 100k FREQUENCY (Hz) Figure 2. Low-Frequency Attenuation for Common DC-Blocking Capacitor Values Maxim Integrated Charge Pump The MAX13330/MAX13331 feature a low-noise charge pump. The 2.2MHz (typ) switching frequency is well beyond the audio range. It does not interfere with the audio signals and avoids AM band interference. The switch drivers feature a controlled switching speed that minimizes noise generated by turn-on and turn-off transients. By limiting the switching speed of the charge pump, the di/dt noise caused by the parasitic bond wire and trace inductance is minimized. Although not typically required, additional high-frequency noise attenuation can be achieved by increasing the value of C2 (see the Typical Application Circuits). 9 MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Diagnostic Output The MAX13330/MAX13331 provides an analog diagnostic output as a fraction of the analog supply voltage VDD. The voltage at DIAG will correspond to the fault condition with the highest priority that is present in the system, as shown in Table 1. When simultaneous fault conditions occur on both headphone outputs, the diagnostic output will only report the fault condition at OUTR until it is cleared or removed. Only then will the fault condition at OUTL be reported at DIAG. Connect DIAG to a high-impedance input. Table 1. MAX13330/MAX13331 Diagnostic Priority VDIAG STATE PRIORITY VDD OUTL Short to VBAT 3 3/4 VDD OUTR Short to VBAT 1 Shutdown 1/2 VDD OUTL Short to SGND 4 The MAX13330/MAX13331 feature shutdown control allowing audio signals to be shut down or muted. Driving SHDN low disables the amplifiers and the charge pump, sets the amplifier output impedance to 14k (typ), and reduces the supply current. In shutdown mode, the supply current is reduced to 2A. The charge pump is enabled once SHDN is driven high. 1/4 VDD 0 Three State OUTR Short to SGND 2 No Fault 5 Shutdown -- For both headphone outputs, short circuits to VBAT are dynamic and VDIAG will be automatically cleared as soon as the fault condition is removed. Short circuits to GND occurring when a positive output voltage is present on OUTL or OUTR, will result in V DIAG being latched until the fault condition is cleared. When VDIAG is latched, it can be cleared by either toggling SHDN low for less than 5s or initiating a full reset of the MAX13330/MAX13331. Toggling SHDN low for less than 5s will cause the fault to ground to be cleared without shutting down the device or interrupting the output state of the amplifiers. A full reset requires SHDN to be pulled low for more than 50s. The amplifier outputs will enter high impedance and remain in that state until the device exits shutdown. Click-and-Pop Suppression In conventional single-supply audio amplifiers, the output-coupling capacitor is a major contributor of audible clicks and pops. Upon startup, the amplifier charges the coupling capacitor to its bias voltage, typically half the supply. Likewise, on shutdown, the capacitor is discharged to SGND. This results in a DC shift across the capacitor which appears as an audible transient at the speaker. Since the MAX13330/MAX13331 does not require output-coupling capacitors, this problem does not arise. 10 Additionally, the MAX13330/MAX13331 feature extensive click-and-pop suppression that eliminates any audible transient sources internal to the device. The Power-Up/-Down Transient graph in the Typical Operating Characteristics shows that there is minimal DC shift and no spurious transients at the output upon startup or shutdown. In most applications, the output of the preamplifier driving the MAX13330/MAX13331 has a DC bias of typically half the supply. At startup, the input-coupling capacitor is charged to the preamplifier's DC-bias voltage through the feedback resistor of the MAX13330/ MAX13331, resulting in a DC shift across the capacitor and an audible click/pop. Delaying the rise of SHDN 4 to 5 time constants (80ms to 100ms) based on RIN and CIN relative to the startup of the preamplifier, eliminates this click/pop caused by the input filter. Applications Information Power Dissipation Under normal operating conditions, linear power amplifiers can dissipate a significant amount of power. The maximum power dissipation for each package is given in the Absolute Maximum Ratings section under continuous power dissipation or can be calculated by the following equation: PDISSPKG(MAX) = (TJ(MAX) - TA ) JA where TJ(MAX) is +145C, TA is the ambient temperature, and JA is the reciprocal of the derating factor in C/W as specified in the Absolute Maximum Ratings section. The thermal resistance JA of the QSOP package is 120C/W. The MAX13330/MAX13331 have two power dissipation sources: the charge pump and two amplifiers. If power dissipation for a given application exceeds the maximum allowed for a particular package, either reduce VDD, increase load impedance, decrease the ambient temperature, or add heatsinking to the device. Large output, supply, and ground traces improve the maximum power dissipation in the package. Maxim Integrated MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Thermal-overload protection limits total power dissipation in the MAX13330/MAX13331. When the junction temperature exceeds +145C (typ), the thermal-protection circuitry disables the amplifier output stage. The amplifiers are enabled once the junction temperature cools by 5C. This results in a pulsing output under continuous thermal-overload conditions. Output Power The device has been specified for the worst-case scenario, when both inputs are in-phase. Under this condition, the amplifiers simultaneously draw current from the charge pump, leading to a proportional reduction in VSS headroom. In typical stereo audio applications, the left and right signals have differences in both magnitude and phase, subsequently leading to an increase in the maximum attainable output power. Figure 4 shows the two extreme cases for in- and out-of-phase. In reality, the available power lies between these extremes. fIN = 1kHz RL = 32 THD+N = 10% OUTPUT POWER (mW) 200 Gain-Setting Resistors (MAX13331 Only) The gain of the MAX13330 is internally set at -1.5V/V. All gain-setting resistors are integrated into the device, reducing external component count. The internally set gain, in combination with DirectDrive, results in a headphone amplifier that requires only five tiny 1F capacitors to complete the amplifier circuit: two for the charge-pump, two for audio input coupling, and one for power-supply bypassing (see the Typical Application Circuits). The gain of the MAX13331 amplifier is set externally as shown in the Typical Application Circuits, the gain is: R A V = - F (V / V ) RIN Choose feedback resistor values of 10k. Values other than 10k increase output offset voltage due to the input bias current, which in turn, increases the amount of DC current flow to the load. OUTPUT POWER vs. SUPPLY VOLTAGE 250 Component Selection INPUTS 180 OUT OF PHASE Input Filtering The input capacitor (CIN), in conjunction with the input resistor (RIN), forms a highpass filter that removes the DC bias from an incoming signal (see the Typical Application Circuits). The AC-coupling capacitor allows the device to bias the signal to an optimum DC level. Assuming zero source impedance, the -3dB point of the highpass filter is given by: 150 INPUTS IN PHASE 100 50 f-3dB = 0 4.00 4.25 4.50 4.75 5.00 5.25 5.50 SUPPLY VOLTAGE (V) Figure 4. Output Power vs. Supply Voltage UVLO The MAX13330/MAX13331 feature a UVLO function that prevents the device from operating if the supply voltage is less than 3.6V (typ). This feature ensures proper operation during brownout conditions and prevents deep battery discharge. Once the supply voltage reaches the UVLO threshold, the charge-pump is turned on and the amplifiers are powered. Maxim Integrated 1 (Hz) 2 x RIN x CIN Choose CIN so f-3dB is well below the lowest frequency of interest. For the MAX13330, use the value of RIN as given in the Electrical Characteristics table. Setting f -3dB too high affects the device's low-frequency response. Use capacitors whose dielectrics have lowvoltage coefficients, such as tantalum or aluminum electrolytic. Capacitors with high-voltage coefficients, such as ceramics, can result in increased distortion at low frequencies. Charge-Pump Capacitor Selection Use capacitors with an ESR less than 100m for optimum performance. Low-ESR ceramic capacitors minimize the output resistance of the charge pump. For best performance over the extended temperature range, select capacitors with an X7R dielectric. 11 MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Flying Capacitor (C1) The value of the flying capacitor (C1) affects the charge pump's load regulation and output resistance. A C1 value that is too small degrades the device's ability to provide sufficient current drive, which leads to a loss of output voltage. Increasing the value of C1 improves load regulation and reduces the charge-pump output resistance to an extent. See the Output Power vs. Load Resistance graph in the Typical Operating Characteristics. Above 1F, the on-resistance of the switches and the ESR of C1 and C2 dominate. Holding Capacitor (C2) The hold capacitor value and ESR directly affect the ripple at CPVSS. Increasing the value of C2 reduces output ripple. Likewise, decreasing the ESR of C2 reduces both ripple and output resistance. Lower capacitance values can be used in systems with low maximum output power levels. See the Output Power vs. Load Resistance graph in the Typical Operating Characteristics. Power-Supply Bypass Capacitor (C3) The power-supply bypass capacitor (C3) lowers the output impedance of the power supply and reduces the impact of the MAX13330/MAX13331 charge-pump switching transients. Bypass CPVDD with C3, the same value as C1, and place it physically close to the CPVDD and PGND pins. 12 Layout and Grounding Proper layout and grounding are essential for optimum performance. Connect CPVDD and VDD together at the device. Connect CPVSS and V SS together at the device. Bypassing of both supplies is accomplished by charge-pump capacitors C2 and C3 (see the Typical Application Circuits). Place capacitors C2 and C3 as close to the device as possible and bypass them to the PGND plane. Keep PGND and all traces that carry switching transients as short as possible to minimize EMI. Route them away from SGND, the audio signal path, and the external feedback components (MAX13331). Connect the PGND plane and the SGND plane together at a single point on the PCB. Refer to the MAX13330/MAX13331 Evaluation Kit for layout guidelines. ESD Protection To pass module level ESD requirements, it may be necessary to add ESD diodes to the MAX13330/MAX13331 outputs. Connect the anode to the CPVSS supply, and connect the cathode to an output pin, as shown in the Typical Application Circuits. Maxim Integrated MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Typical Application Circuits 4V to 5.5V 0.33F C3 1F LEFT CHANNEL AUDIO IN SHDN UVLO/ SHUTDOWN CONTROL INL 45k VDD 30k C1P VSS C1 1F CHARGE PUMP CLICK-AND-POP SUPPRESSION VSS C1N 30k MAX13330 VDD VSS C2 1F Maxim Integrated CPVSS PGND SGND INR 0.33F OUTPUT PROTECTION AND DIAGNOSTICS VDD CPVDD OUTL 1nF DIAG 10nF OUTR 1nF 45k RIGHT CHANNEL AUDIO IN ESD PROTECTION DIODES CPVSS 13 MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Typical Application Circuits (continued) RIN 30k CIN 0.33F LEFT CHANNEL AUDIO IN 4V to 5.5V RF 45k C3 1F SHDN INL VDD UVLO/ SHUTDOWN CONTROL C1P OUTPUT PROTECTION AND DIAGNOSTICS VDD CPVDD VSS C1 1F CHARGE PUMP CLICK-AND-POP SUPPRESSION VSS C1N MAX13331 OUTL 1nF DIAG 10nF OUTR VDD VSS CPVSS PGND SGND 1nF ESD PROTECTION DIODES INR C2 1F RIN 30k CPVSS RF 45k CIN 0.33F RIGHT CHANNEL AUDIO IN Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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. 14 PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 16 QSOP E16+1 21-0055 90-0167 Maxim Integrated MAX13330/MAX13331 Automotive DirectDrive Headphone Amplifiers with Output Protection and Diagnostics Revision History PAGES CHANGED REVISION NUMBER REVISION DATE 0 10/08 1 4/09 Corrected the Features section for THD+N, style edits 2 5/11 Updated the continuous power dissipation numbers in the Absolute Maximum Ratings section; added the Package Thermal Characteristics section; added the ESD Protection section; updated the Typical Application Circuits to add the ESD protection diodes 2, 12, 13, 14 3 7/11 Corrected the units for the click-and-pop level parameter from V to dB in the Electrical Characteristics table 3 4 11/15 Corrected package code 14 DESCRIPTION Initial release -- 1, 2, 3, 15 Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated 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 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 ________________________________ 15 (c) 2015 Maxim Integrated Products, Inc. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Maxim Integrated: MAX13330GEE/V+ MAX13330GEE/V+T MAX13331GEE/V+ MAX13331GEE/V+T