PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Features General Description n 3W Output at 10% THD with a 4 Ω Load and 5V Power Supply n Filterless, Low Quiescent Current and Low EMI n Low THD+N n 64-Step DC Volume Control from -75dB to +24dB n Superior Low Noise n Efficiency up to 89% n Short Circuit Protection n Thermal Shutdown n Few External Components to Save the Space and Cost n Pb-Free Package The PAM8603M is a 3W, sterero, class-D audio amplifier with DC volume control. It offers low THD+N, allowing it to produce high-quality sound reproduction. The new filterless architecture allows the device to drive the speaker directly, requiring no low-pass output filters , which saves the system cost and PCB area. With the same numbers of external components, the efficiency of the PAM8603M is much better than class-AB cousins. It can extend the battery life thus ideal for portable applications. The PAM8603M is available in SSOP-24 and SOP-18 packages. Applications n n n n n LCD Monitors/TV Projectors Notebook Computers Portable Speakers Portable DVD Players, Game Machines Cellular Phones/Speaker Phones Typical Application Circuit Efficiency vs Output Power PVDDL 100 10μF 90 80 PVDDL Efficiency(%) 1μF PGNDL +OUTL +OUTR -OUTL -OUTR 70 RL=4Ω 60 RL=8Ω 50 40 30 20 0 0.47 μF 0.47μF INL 10 INL INR PAM8603M INR VREF 0.5 1 1.5 2 2.5 3 Output Pow er(W) VDD 1μF 0 VDD 1μF Radiated Emissions ON SHDN VDC MUTE VOLUME SHDN ON 50kO FCC Class B Limit MUTE PVDDR PGNDR GND 1μF 10μF PVDDR Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 1 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Block Diagram PVDDR PGNDR VDD VDD/2 + INR + - +OUTR DRIVER -OUTR MODULATOR THERMAL PROTECTION MUTE SHDN Attenuation Decoder Interface Control VDC VOLUME INTERNAL OSCILLATOR BIAS AND REFERENCES VREF OSC CURRENT PROTECTION MODULATOR INL + - +OUTL DRIVER -OUTL + VDD/2 GND PVDDL PGNDL Pin Configuration & Marking Information Top View SSOP-24 2 3 4 5 MUTE 6 VDD 7 INL 8 NC 9 VDC10 VOLUME 11 NC12 +OUTL PGNDL -OUTL PVDDL MUTE VDD INL VDC VOLUME 22 PGNDR 21 -OUTR 20 PVDDR 19 SHDN 18 GND 17 INR 16 NC 1 2 3 4 5 6 7 8 9 PAM8603M XXXYWWXX 24 +OUTR 23 PGNDR 1 PAM8603M XXXYWWXX +OUTL PGNDL PGNDL -OUTL PVDDL Top View SOP-18 18 17 16 15 14 13 12 11 10 +OUTR PGNDR -OUTR PVDDR SHDN GND INR NC VREF 15 NC 14 VREF 13 NC X: Internal Code Y: Year WW: Week Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 2 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Pin Descriptions Pin Name SSOP-24 SOP-18 Description +OUTL 1 1 Left Channel Positive Output PGNDL 2,3 2 Left Channel Power GND -OUTL 4 3 Left Channel Negative Output PVDDL 5 4 Left Channel Power Supply MUTE 6 5 Mute Control Input（active low） VDD 7 6 Analog Power Supply INL 8 7 Left Channel Input NC 9, 12,13,15,16 11 No Connect VDC 10 8 Analog reference for gain control section VOLUME 11 9 DC volume control to set the gain of Class-D VREF 14 10 Internal analog reference, connect a bypass capacitor from VREF to GND INR 17 12 Right Channel Input GND 18 13 Analog Ground SHDN 19 14 Shutdown Control Input(active low) PVDDR 20 15 Right Channel Power Supply -OUTR 21 16 Right Channel Negative Output PGNDR 22,23 17 Right Channel Power GND +OUTR 24 18 Right Channel Positive Output Absolute Maximum Ratings These are stress ratings only and functional operation is not implied . Exposure to absolute maximum ratings for prolonged time periods may affect device reliability . All voltages are with respect to ground . Supply Voltage ............................................6.6V Input Voltage.............................-0.3V to V DD+0.3V Maximum Junction Temperature..................150 °C Storage Temperature.....................-65°C to 150 °C Soldering Temperature...................... 300°C, 5sec Recommended Operating Conditions Supply Voltage Range....................... 2.8V to 5.5V Max. Supply Voltage (for Max. duration of 30 minutes)................................................6.4V Junction Temperature Range.........-40 °C to 125 °C Ambient Temperature Range............-40 °C to 85 °C Thermal Information Parameter Symbol Thermal Resistance (Junction to Ambient) θJA Thermal Resistance (Junction to Case) θJc Package Maximum Unit SSOP-24 96 °C/W SOP-18 70 °C/W SSOP-24 18 °C/W SOP-18 16 °C/W Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 3 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Electrical Characteristic V DD=5V, Gain=20dB,T A=25 °C, unless otherwise noted. Symbol VDD Parameter Test Conditions Supply Voltage THD+N=1%, f=1kHz, RL=4Ω Output Power THD+N=10%, f=1kHz,RL=8Ω THD+N=1%,f=1kHz,R L=8Ω VDD =5.0V,Po=0.5W,RL=8Ω THD+N Total Harmonic VDD =3.6V,Po=0.5W,RL=8Ω Distortion Plus Noise VDD =5.0V,Po=1W,R L=4Ω Cs SNR Vn Dyn η Power Supply Ripple Rejection VDD =5.0V, Inputs ac-grounded 2.85 3.2 V DD =3.6V 1.55 1.8 V DD =5.0V 2.35 2.6 V DD =3.6V 1.25 1.5 V DD =5.0V 1.55 1.8 V DD =3.6V 0.75 0.9 V DD =5.0V 1.15 1.4 V DD =3.6V 0.5 0.72 0.15 0.3 0.11 0.25 f=100Hz -59 -50 f=1kHz -58 -50 -95 -80 VDD =5V, Vo_rms=1V, f=1kHz 85 IMUTE IS D Rdson 98 A-weighting 75 150 with Cin=0.47μF No A-weighting 120 300 VDD =5.0V, THD=1%, f=1kHz RL=8Ω, THD=10% f=1kHz 102 85 89 80 85 dB μV dB % VDD =3.6V 8.5 15 Muting Current VDD =5.0V, V MUTE=0.3V 2.7 5 mA Shutdown Current VDD =2.5V to 5.5V, VS D=0.3V 1 μA Static Drain-to-source On-state Resistor IDS =500mA,Vgs=5V 240 500 NMOS 180 350 260 300 kHz 10 50 mV VDD =3V to 5V Vos Output Offset Voltage Vin=0V, V DD =5V VIH SD/MUTE Input High VDD =5V 1.45 V IL SD/MUTE Input Low VDD =5V 0.65 200 Over Temperature Protection No Load, Junction Temperature, VDD=5V Over Temperature Hysterisis mA PMOS Switching Frequency OTH dB 20 No load fsw OTP % 13.5 Quiescent Current VDD =5V 90 % dB VDD =5V, Inputs ac-grounded RL=4Ω, THD=10% IQ W 0.25 Signal-to-noise ratio Efficiency W 0.11 VDD =5V,Po=0.5W, R L=8Ω,f=1kHz Dynamic range W 0.3 f=1kHz V W 0.15 f=1kHz Crosstalk Output noise MAX UNIT 5.5 V DD =5.0V VDD =3.6V,Po=1W,R L=4Ω PSRR TYP 2.8 THD+N=10%, f=1kHz,RL=4Ω Po MIN 135 mΩ V °C 30 Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 4 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Typical Operating Characteristics (T =25°C) A 1. Efficiency VS Output Power 100 100 90 90 80 80 V DD=5V 60 50 V DD=3.6V 40 70 Efficiency (%) Efficiency (%) 70 30 2. Efficiency VS Output Power V DD=5V 60 50 V DD=3.6V 40 30 20 20 10 10 R L=8 Ω 0 0 0.5 1 1.5 R L=4 Ω 0 2 0 0.5 1 R L=4 Ω Gain=20dB f=1kHz 10 5 V DD=5V V DD=5V 2 V DD=3.6V 1 1 V DD=3.6V % 0.5 % 0.5 0.2 0.2 0.1 0.1 0.05 . 0 05 0.02 0.02 0.01 10m 0.01 20m 50m 100 m 200 m 500 m 1 2 10 m 4 20 m 50 m 100m 5. THD+N VS Frequency 500m 1 2 4 6. THD+N VS Frequency 10 10 Po=0.5W R L=8 Ω Cin=0.47 μ F Gain=20dB 5 2 2 % 200m W W 5 3 30 20 R L=8 Ω Gain=20dB f=1kHz 2 2.5 4.THD+N VS Output Power 3.THD+N VS Output Power 30 5 2 Output Pow er (W) Output Pow er (W) 10 1.5 1 % 1 0.5 V DD=5V 0.5 Po=1W R L=4 Ω Cin=0.47 μ F Gain=20dB V DD=3.6V 0.2 0.2 V DD=5V V DD=3.6V 0.1 20 50 100 200 500 1k 2k 5k 0.1 10k 0.08 20 20k 50 100 200 500 1k 2k 5k 10k 20k Hz Hz Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 5 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Typical Operating Characteristics (T =25°C) A 7. Frequency Response 8.PSRR VS Frequency +5 +0 Gain=0dB@1kHz Cin=0.47 μ F, R L=8 Ω V DD=3.6V/5V +4 +3 -20 +2 -30 +1 d B r -40 d B +0 A Inputs ac-ground V DD=5V,100mVpp, Cin=0.47 μ F,R L=8 Ω -10 -50 -1 -60 -2 -70 -3 -80 -4 -90 -5 20 50 100 200 500 1k 2k 5k 10k -100 20 20k 30k 50 100 200 500 9. Crosstalk VS Frequency -50 T T T T T T -55 +0 T T T -65 -30 -40 -50 -75 R to L -70 -80 -90 A -95 -90 -100 -100 -110 -105 -120 -110 -130 L to R -115 -120 20 50 100 200 500 1k -140 2k 5k 10k -150 20 20k 50 100 200 11. Quiescent Current VS Supply Voltage 0.3 No input RL=No Load Shutdown Current(uA) Quiescent Current(mA) 500 1k 2k 5k 10k 20k Hz Hz 18 16 14 12 10 8 6 4 2 0 10k -60 d B r -80 -85 5k Inputs ac-ground, V DD=5.0V Cin=0.47 μ F, R L=8 Ω -20 -70 d B 2k 10. Noise Floor FFT -10 Gv=20dB ,R L=4 V DD=5.0V, Po=0.5W -60 1k Hz Hz 0.25 12. Shutdown Current VS Supply Voltage No input No Load 0.2 0.15 0.1 0.05 0 2.5 3 3.5 4 4.5 5 2.5 5.5 3 3.5 4 4.5 5 5.5 Power Supply Voltage(V) Power Supply Voltage(V) Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 6 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Typical Operating Characteristics (T =25°C) A 13. Output Power VS Supply Voltage Output Power(W) R L=8 Ω R L=4 Ω 3.5 THD=10% 2 14. Output Power VS Supply Voltage 4 Output Power(W) 2.5 1.5 1 THD=1% 0.5 THD=10% 3 2.5 2 1.5 THD=1% 1 0.5 0 0 2.5 255 250 5.5 2.5 3 15. Rdson VS Output Current PMOSFET Vgs=-5V 240 235 230 225 220 4.5 5 5.5 NMOSFET Vgs=5V 170 168 166 164 162 160 158 156 154 215 50 100 200 300 400 50 500 750 1000 1500 100 200 300 400 500 750 1000 1500 Drain-source Current(mA) Drain-source Current(mA) 18. Gain Control VS Volume Voltage 17. Frequency VS Supply Voltage 40 Input AC-ground V DD=5V 20 0 Gain(dB) Frequency(KHz) 4 16. Rdson VS Output Current 172 245 300 290 280 270 260 250 240 230 220 210 200 3.5 Power Supply Voltage(V) Drain-source Resistance(Ω) Drain-source Resistance(Ω) 260 3 3.5 4 4.5 5 Power Supply Voltage(V) -20 -40 -60 -80 3 3.5 4 4.5 5 0.1 0.2 0.4 0.5 0.7 0.8 0.9 1.1 1.2 1.4 1.5 1.6 1.8 1.9 2.1 2.2 2.3 2.5 2.6 2.8 2.9 3.0 3.2 3.3 3.5 3.6 3.7 3.9 4.0 4.2 4.3 4.4 5.5 Volume Voltage(V) Power Supply Voltage(V) Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 7 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Table 1. DC Volume Control STEP Gain (dB) STEP Gain (dB) 0 -75 32 11.6 1 -40 33 12 2 -34 34 12.4 3 -28 35 12.8 4 -22 36 13.2 5 -16 37 13.6 6 -10 38 14 7 -7.5 39 14.4 8 -5 40 14.8 9 -2.5 41 15.2 10 0 42 15.6 11 1.5 43 16 12 3 44 16.4 13 4 45 16.8 14 4.4 46 17.2 15 4.8 47 17.6 16 5.2 48 18 17 5.6 49 18.4 18 6 50 18.8 19 6.4 51 19.2 20 6.8 52 19.6 21 7.2 53 20 22 7.6 54 20.4 23 8 55 20.8 24 8.4 56 21.2 25 8.8 57 21.6 26 9.2 58 22 27 9.6 59 22.4 28 10 60 22.8 29 10.4 61 23.2 30 10.8 62 23.6 31 11.2 63 24 Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 8 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control 3. The input signal should not be too high. If too high, it will cause the clipping of output signal when increasing the volume. Because the DC volume control of the PAM8603M has big gain, it will make the device damaged. Application Notice 1. When the PAM8603M works with LC filters, it should be connected with the speaker before it is powered on, otherwise it will be damaged easily. 4. When testing the PAM8603M without LC filters by using resistor instead of speaker as the output load, the test results, e.g. efficiency, will be worse than those using speaker as load. 2. When the PAM8603M works without LC filters, it's better to add a ferrite chip bead at the outgoing line of speaker to suppress the possible electromagnetic interference. Test Setup for Performance Testing PAM8603M Demo Board Load +OUT AP System AP LPF Input Generator AUX-0025 GND AP System Analyzer - OUT V DD Power Supply Notes 1. The AP AUX-0025 low pass filter is necessary for class-D amplifier measurement done by AP analyzer. 2. Two 22 μ H inductors are used in series with load resistor to emulate the small speaker for efficiency measurement. Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 9 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Application Information case, input capacitor (C i) and input resistance (R i) of the amplifier form a high-pass filter with the corner frequency determined equation below, Mute Operation The MUTE pin is an input for controlling the output state of the PAM8603M. A logic low on this pin disables the outputs, and a logic high enables the outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade. Quiescent current is listed in the electrical characteristic table. The MUTE pin can be left floating due to the internal pull-up . 1 2πRiCi In addition to system cost and size, click and pop perfor mance is affected by the size of the input coupling capacitor, C i. A larger input coupling capacitor requires more charge to reach its quiescent DC voltage (nominally 1/2 V DD). This charge comes from the internal circuit via the feedback and is apt to create pops upon device enable. Thus, by minimizing the capacitor size based on necessary low frequency response, turn-on pops can be minimized. fC= For better power-off pop performance, the amplifier should be placed in the mute mode prior to removing the power supply. Shutdown Operation In order to reduce power consumption while not in use, the PAM8603M contains shutdown circuitry to turn off the amplifier's bias circuitry. The amplifier is turned off when logic low is placed on the SHDN pin. By switching the SHDN pin connected to GND, the PAM8603M supply current draw will be minimized in idle mode. The SHDN pin can be left floating due to the internal pull-up. Analog Reference Bypass Capacitor (C BYP) The Analog Reference Bypass Capacitor (C BYP) is the most critical capacitor and serves several important functions. During start-up or recovery from shutdown mode, C BYP determines the rate at which the amplifier starts up. The second function is to reduce noise produced by the power supply coupling in the output drive signal. This noise is from the internal analog reference to the amplifier which appears as degraded PSRR and THD+N. Power Supply Decoupling The PAM8603M is a high performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output THD and PSRR as low as possible. Power supply decoupling affects low frequency response. Optimum decoupling is achieved by using two capacitors of different types that target different noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-series resistance (ESR) ceramic capacitor, typically 1.0 μ F, placed as close as possible to the device VDD terminal works best. For filtering lower-frequency noise signals, a large capacitor of 10μF (ceramic) or greater placed near the audio power amplifier is recommended. A ceramic bypass capacitor (C BYP) of 0.47μF to 1.0μF is recommended for the best THD and noise performance. Increasing the bypass capacitor reduces clicking and popping noise from power on/off and entering and leaving shutdown. Under Voltage Lock-out (UVLO) The PAM8603M incorporates circuitry to detect low supply voltage. When the supply voltage drops to 1.8V or below, the PAM8603M outputs are disable. The device resumes to normal functional once V DD ≥2.0V. Short Circuit Protection (SCP) The PAM8603M has short circuit protection circuitry on the outputs to prevent the device from damage when output-to-output or output-to-GND short. When a short circuit is detected on the outputs, the outputs are disable immediately. If the short was removed, the device activates again. Input Capacitor (C i) Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certain sized capacitor is needed to couple in low frequencies without severe attenu ation. But in many cases the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 100Hz to 150Hz. Thus, using a large input capacitor may not increase actual system perfor mance. In this Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 10 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control PCB Layout Guidelines Grounding At this stage it is paramount to notice the necessity of separate grounds. Noise currents in the output power stage need to be returned to output noise ground and nowhere else. Were these currents to circulate elsewhere, they may get into the power supply, the signal ground, etc, even worse, they may form a loop and radiate noise. Any of these cases results in degraded amplifier performance. The logical returns for the output noise currents associated with Class-D switching are the respective PGND pins for each channel. The switch state diagram illustrates that PGND is instrumental in nearly every switch state. This is the perfect point to which the output noise ground trace should return. Also note that output noise ground is channel specific. A twochannel amplifier has two seperate channels and consequently must have two seperate output noise ground traces. The layout of the PAM8603M offers separate PGND connections for each channel and in some cases each side of the bridge. Output noise grounds must be tied to system ground at the power exclusively. Signal currents for the inputs, reference, etc need to be returned to quite ground. This ground is only tied to the signal components and the GND pin, and GND then tied to system ground. Over Temperature Protection Thermal protection on the PAM8603M prevents the device from damage when the internal die temperature exceeds 135°C. There is a 15 degree tolerance on this trip point from device to device. Once the die temperature exceeds the thermal set point, the device outputs are disabled. This is not a latched fault. The thermal fault is cleared once the temperature of the die is reduced by 30 °C . This large hysteresis will prevent motor boating sound well. The device begins normal operation at this point without external system interaction. How to Reduce EMI (Electro Magnetic Interference) A simple solution is to put an additional capacitor 1000 μ F at power supply terminal for power line coupling if the traces from amplifier to speakers are short (<20cm). Most applications require a ferrite bead filter as shown at Figure 3. The ferrite filter reduces EMI of around 1 MHz and higher. When selecting a ferrite bead, choose one with high impedance at high frequencies, and low impedance at low frequencies (MH2012HM221-T). Ferrite Bead OUT+ 200pF Ferrite Bead OUT200pF Figure 3: Ferrite Bead Filter to Reduce EMI Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 11 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Ordering Information PAM8603M X X X Shipping Package (R: Tape & Reel, T: Tube) Number of Pins (H: 24, E: 18) Package Type (N: SSOP, D: SOP) Part Number PAM8603MNHR PAM8603MDER PAM8603MDET Marking PAM8603M XXXYWWLL PAM8603M XXXYWWLL PAM8603M XXXYWWLL Package Type MOQ/Shipping Package SSOP-24 2,500 Units/Tape & Reel SOP-18 1,000 Units/Tape & Reel SOP-18 40 Units/Tube Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 12 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Outline Dimension SSOP-24 Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 13 PAM8603M 3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control Outline Dimension SOP-18 D A3 0.25 A2 A c θ A1 L L1 b b1 E1 E c1 C BASE METAL WITH PLATING SECTION B-B b B e SYMBOL B MILLIMETER MIN NOM MAX A - - 2.70 A1 0.08 0.18 0.30 A2 2.10 2.30 2.50 A3 0.92 1.02 1.12 b 0.35 - 0.44 b1 0.34 0.37 0.39 c 0.26 - 0.31 c1 0.24 0.25 0.26 D 11.25 11.45 11.76 E 10.00 10.30 10.64 E1 7.30 7.50 7.70 e L 1.27BSC 0.70 L1 θ 0.85 1.00 1.40BSC 0° - 8° Power Analog Microelectronics , Inc www.poweranalog.com 10/2008 Rev 1.0 14