PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Key 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 Superior Low Noise n Efficiency up to 90% n Short Circuit Protection n Thermal Shutdown n Few External Components to Save the Space and Cost n Pb-Free Package The PAM8403 is a 3W, class-D audio amplifier. It offers low THD+N, allowing it to achieve highquality sound reproduction. The new filterless architecture allows the device to drive the speaker directly, requiring no low-pass output filters,thus to save the system cost and PCB area. With the same numbers of external components, the efficiency of the PAM8403 is much better than that of class-AB cousins. It can extend the battery life, ideal for portable applications. The PAM8403 is available in SOP-16 package. 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 Efficiency vs Output Power 100 90 1μF 470μF 1μF 6 VDD 0.47μF 80 PVDD Efficiency(%) VDD 1μF 13 4 PVDD PVDD 7 INL +OUT_L VREF -OUT_L RL=4Ω 60 50 40 30 10 1 0 0 8 0.1μF PAM8403 0.47μF 10 INR Ri 12 SHDN 5 MUTE -OUT_R INR SHDN +OUT_R 3 14 2 1 1.5 2 2.5 3 Radiated Emissions 16 FCC Class B Limit GND NC PGNDPGND 9 0.5 Output Pow er(W) MUTE 11 RL=8Ω 20 Ri INL 70 15 Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 1 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Block Diagram VDD PVDD PGND VDD/2 + - INR +OUT_R DRIVER -OUT_R MODULATOR SHDN ATTENUATION DECODER INTERFACE CONTROL MUTE THERMAL PROTECTION INTERNAL OSCILLATOR BIAS AND REFERENCES VREF OSC CURRENT PROTECTION MODULATOR INL +OUT_L DRIVER + -OUT_L VDD/2 GND PVDD PGND Pin Configuration & Marking Information Top View SOP-16 1 16 2 15 4 5 PAM8403 XATYWWLL 3 X: Internal Code A: Assembly Code T: Testing Code Y: Year WW: Week LL: Internal Code 14 13 12 6 11 7 10 8 9 Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 2 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Pin Descriptions Pin Number Pin Name Description 1 +OUT_L Left Channel Positive Output 2 PGND 3 -OUT_L 4 PVDD Power VDD 5 MUTE Mute Control Input（active low） 6 VDD Analog VDD 7 INL Left Channel Input 8 VREF 9 NC No connect 10 INR Right Channel Input 11 GND Analog GND 12 SHDN Shutdown Control Input (active low) 13 PVDD Power VDD 14 -OUT_R 15 PGND 16 +OUT_R Power GND Left Channel Negative Output Internal analog reference, connect a bypass capacitor from VREF to GND Right Channel Negative Output Power GND 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 Operation Temperature Range.........-40°C to 85 °C Maximum Junction Temperature..................150°C Operation Junction Temperature.....-40 °C to 125 °C Storage Temperature.....................-65 °C to 150 °C Soldering Temperature....................... 300°C, 5sec Recommended Operating Conditions Supply voltage Range........................ 2.5V to 5.5V Max. Supply Voltage (for Max. duration of 30 minutes)................................................6.4V Operation Temperature Range.........-40 °C to 85 °C Junction Temperature Range.........-40 °C to 125 °C Thermal Information Parameter Symbol Package Maximum Unit Thermal Resistance (Junction to Ambient) θJA SOP-16 110 °C/W Thermal Resistance (Junction to Case) θJC SOP-16 23 °C/W Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 3 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Electrical Characteristic V DD=5V, Gain=24dB, R L=8 Ω , T A=25 °C , unless otherwise noted. Symbol Parameter VIN Supply Power Test Conditions THD+N=1%,f=1kHz, RL =4 Ω Output Power THD+N=10%,f=1kHz, RL =8 Ω THD+N=1%,f=1kHz, RL =8 Ω VDD=5.0V,Po=0.5W,RL=8 Ω THD+N Total Harmonic Distortion Plus VDD=3.6V,Po=0.5W,RL=8 Ω Noise VD D=5.0V,Po=1W,RL =4 Ω VD D=3.6V,Po=1W,RL =4 Ω Gv Gain PSRR Power Supply Ripple Rejection TYP 2.5 THD+N=10%,f=1kHz, RL =4 Ω Po MIN 5.5 VDD=5.0V 3.2 VDD=3.6V 1.6 VDD=3.0V 1.3 VDD=5.0V 2.5 VDD=3.6V 1.3 VDD=3.0V 0.85 VDD=5.0V 1.8 VDD=3.6V 0.9 VDD=3.0V 0.6 VDD=5.0V 1.4 VDD=3.6V 0.72 VDD=3.0V 0.45 f=1kHz MAX UNIT 0.15 V W W W W % 0.11 f=1kHz 0.15 0.11 24 VD D=5.0V, Inputs ac-grounded with f=100Hz -59 CIN =0.47μF f=1kHz -58 % dB dB Cs Crosstalk VDD=5V,Po=0.5W,RL =8Ω,Gv=20dB F=1kHz -95 dB SNR Signal-to-noise ratio VDD=5V, Vorms=1V,Gv=20dB f=1kHz 80 dB Vn Output noise VDD=5V, Inputs ac-grounded with A-weighting 100 CIN =0.47μF No A-weighting 150 VDD=5.0V, THD=1% f=1kHz 90 Dyn Dynamic range η Efficiency R L=8Ω, THD=10% R L=4Ω, THD=10% f=1kHz VDD=5.0V IQ Quiescent Current VDD=3.6V VDD=3.0V 87 83 μV dB % 16 No load 10 mA 8 Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 4 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Electrical Characteristic (Continued) V DD=5V Gain=24dB, R L=8 Ω , T A=25 °C , unless otherwise noted. Symbol Parameter IMUT E Muting Current VDD=5.0V VMUTE =0.3V 3.5 mA ISD Shutdown Current VDD=2.5V to 5.5V Vsd=0.3V <1 μA PMOS 180 NMOS 140 Rdson Static Drain-to-source On-state Resistor Test Conditions IDS =500mA,Vgs=5V MIN TYP MAX UNIT mΩ fsw Switching Frequency VDD=3V to 5V 260 kHz Vos Output Offset Voltage Vin=0V, VDD=5V 10 mV VIH Enable Input High Voltage VDD=5.0V VIL Enable Input Low Voltage VDD=5.0V VIH MUTE Input High Voltage VDD=5.0V VIL MUTE Input Low Voltage VDD=5.0V OTP Over Temperature Protection OTH Over Temperature Hysterisis No Load, Junction Temperature 1.5 1.4 0.7 1.5 1.4 0.7 VDD=5V 0.4 140 30 0.4 V V °C Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 5 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Typical Operating Characteristics (T =25°C) A 2. THD+N vs Output Power 1. THD+N vs Output Power 100 100 50 50 V DD=3.3V 20 10 10 V DD=2.5V 5 5 2 % 2 % 1 1 0.5 0.5 0.2 0.2 0.1 0.1 0.05 0.05 V DD=5V 0.02 0.01 20m 50m 100m 200m 500m 1 2 V DD=5V 0.02 0.01 20m 4 50m 100m 200m 500m 1 2 4 W W R L=4 Ω , Gain = 24dB, f=1kHz R L=8 Ω , Gain = 24dB, f=1kHz 3. THD+N vs Frequency 4. THD+N vs Frequency 100 100 50 50 20 20 10 10 5 5 2 % V DD=3.3V V DD=2.5V 20 2 1 % 0.5 1 0.5 L 0.2 0.2 0.1 0.1 0.05 0.05 0.02 L 0.02 0.01 20 R 50 100 200 500 1k 2k 5k 10k 0.01 20 20k Hz R 50 100 200 500 1k 2k 5k 10k 20k Hz V DD=5V, R L=8 Ω ,Gain = 24dB, Cin=1 μ F V DD=5V, R L=4 Ω ,Gain = 24dB, Cin=1 μ F Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 6 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Typical Operating Characteristics (continued) 5. Frequency response 6. Crosstalk VS Frequency +0 +24.4 L T TTTTTTTT TTT -10 +24.2 -20 +24 -30 +23.8 d B r R -40 +23.6 -50 d B +23.4 -60 A -70 +23.2 -80 +23 L -90 +22.8 -100 R +22.6 10 20 50 100 200 500 1k 2k 5k 10k -110 20 20k 50 100 200 500 1k 2k 5k 10k 20k Hz Hz V DD=5V, R L=4 Ω , Gv=24dB, Po=0.5W V DD=5V, R L=8 Ω ,Gain = 24dB, Cin=1 μ F 7. Noise Floor FFT d B V +0 +0 -10 -10 -20 -20 -30 -30 -40 -40 -50 -50 -60 -60 -70 -80 -70 L -80 -90 -90 -100 -100 -110 -120 20 d B V -110 R 50 100 200 500 1k 2k 5k 10k 20k -120 Hz Inputs ac-ground, V DD=5V, R L=8 Ω ,Cin=1 μ F Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 7 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier probably damage the device. Therefore, it's recommended to use either 4 Ni-MH (Nickel Metal Hydride) rechargeable batteries or 3 dry or alkaline batteries. Application Notes 1. When the PAM8403 works with LC filters, it should be connected with the speaker before it's powered on, otherwise it will be damaged easily. 4. One should not make the input signal too large. Large signal can cause the clipping of output signal when increasing the volume. This will damage the device b ecause of big gain of the PAM8403 . 2. When the PAM8403 works without LC filters, it's better to add a ferrite chip bead at the outgoing line of speaker for suppressing the possible electromagnetic interference. 5. When testing the PAM8403 without LC filters by using resistor instead of speaker as the output load, the test results, e.g. THD or efficiency, will be worse than those of using speaker as load. 3. The recommended operating voltage is 5.5V. When the PAM8403 is powered with 4 battery cells, it should be noted that the voltage of 4 new dry or alkaline batteries is over 6.0V, higher than its operation voltage, which will Test Setup for Performance Testing PAM8403 Demo Board Load +OUT AP System One Generator Input AP Low Pass Filter GND -OUT AP System One Analyzer AUX-0025 VDD Power Supply Notes 1. The AP AUX-0025 low pass filter is necessary for class-D amplifier measurement with AP analyzer. 2. Two 22µH inductors are used in series with load resistor to emulate the small speaker for efficiency measurement. Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 8 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Application Information Maximum Gain resistance (ESR) ceramic capacitor, typically 1.0μF, works best, placing it as close as possible to the device V DD terminal. For filtering lowerfrequency noise signals, a large capacitor of 20μF (ceramic) or greater is recommended, placing it near the audio power amplifier. As shown in block diagram (page 2), the PAM8403 has two internal amplifier stages. The first stage's gain is externally con figurable, while the second stage's is internally fixed. The closed-loop gain of the first stage is set by selecting the ratio of R f to R i while the second stage's gain is fixed at 2x.The output of amplifier 1 serves as the input to amplifier 2, thus the two amplifiers produce signals identical in magnitude, but different in phase by 180°. Consequently, the differential gain for the IC is 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 case, input capacitor (C i) and input resistance (R i) of the amplifier form a high-pass filter with the corner frequency determined by equation below, 1 fC= 2πRiCi A VD=20*log [2*(R f/R i)] T h e PA M 8 4 0 3 s e t s m a x i m u m R f = 1 4 2 k Ω , minimum R i=18k Ω , so the maximum closed-gain is 24dB. Mute Operation The MUTE pin is an input for controlling the output state of the PAM8403. A logic low on this pin disables the outputs, and a logic high on this pin 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. 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. Shutdown operation In order to reduce power consumption while not in use, the PAM8403 contains shutdown circuitry to turn off the amplifier's bias circuitry. This shutdown feature turns the amplifier off when logic low is applied to the SHDN pin. By switching the SHDN pin connected to GND, the PAM8403 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 caused by the power supply coupling into 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 PAM8403 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 targeting to different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-series- A ceramic bypass capacitor (C BYP) with values 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. Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 9 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier How to Reduce EMI (Electro Magnetic Interference) Under Voltage Lock-out (UVLO) The PAM8403 incorporates circuitry designed to detect low supply voltage. When the supply voltage drops to 2.0V or below, the PAM8403 outputs are disabled, and the device comes out of this state and starts to normal function when V DD ≥2.2V. 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 in Figure 2. 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. Short Circuit Protection (SCP) The PAM8403 has short circuit protection circuitry on the outputs to prevent damage to the device when output-to-output or output-to-GND short occurs. When a short circuit is detected on the outputs, the outputs are disabled immediately. If the short was removed, the device activates again. Ferrite Bead OUT+ Over Temperature Protection 220pF Ferrite Bead Thermal protection on the PAM8403 prevents the device from damage when the internal die temperature exceeds 140°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 and the device begins normal operation at this point without external system intervention. OUT220pF Figure 2: Ferrite Bead Filter to reduce EMI Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 10 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Ordering Information PAM8403 X X Shipping Package Package Type Part Number PAM8403DR Marking Package Type MOQ/Shipping Package SOP-16 2,500 Units/Tape&Reel PAM8403 XATYWWLL Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 11 PAM8403 Filterless 3W Class-D Stereo Audio Amplifier Outline Dimension A1 A A2 SOP-16 B D E E1 L C θ e Symbol Dimensions Millimeters Min Max A 1.350 1.750 A1 0.100 0.250 A2 1.350 1.550 B 0.330 0.510 C 0.190 0.250 D 9.800 10.000 E 3.800 4.000 E1 5.800 6.300 e 1.270(TYP) L 0.400 1.270 θ 0º 8º Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.3 12