PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Key Features Applications n 32W/ch into 8ohm BTL Load from 24V supply (Thermal limited) n 16W / ch into 4ohm SE Load from 24V supply ( Thermal limited ) n Operates from 8V to 30V n Supports Multiple Output Configurations : n 2-Ch Single-ended (half - bridge)(16WX2) n 1 - Ch Bridge - tied load ( full - bridge ) ( 32WX1) n High efficiency , above 90 % . n 64 - setp DC Volume Control from - 40dB to 36dB n Singel - Ended Analog Inputs n Thermal and Short- Circuit Protection n Flexible Frequency Adjustable by external component n Clock Output for Synchronization With Multiple Class - D Devices n No pop noise for Start- up and Shut- down Sequences n Space - Saving Surface - Mount 24 - Pin TSSOP Package n Pb-Free Package n Televisions n Home sound systems General Description The PAM8615 is a 16W/ 32W ( per channel) efficient , Class - D audio power amplifier for driving stereo speakers in a single - ended configuration or mono bridge - tied speaker . The PAM8615 can drive single - ended speakers as low as 4Ω . Due to the low power dissipation and high efficiency the device can be used without any external heat sink when playing music . Stereo speaker volume is controlled with a dc voltage applied to the volume control terminal offering a range of gain from - 40 dB to 36 dB. Th e PA M8 6 15 i s a v a il a bl e in a TS S O P - 24 package. Typical Application VC C 470u F 10uF 0.1u F 22 uH 1 2 ON 3 SHD N MU TE ON 4 1 uF Ri 5 IN A 6 Ri 1 uF 7 IN B 1u F 8 9 V olu me 10 11 VC C 12 470u F 10uF OU T_ A OU T_ A PVC C_ A PGND _ A SH D N BS T_ A MU TE AVC C IN _A AVD D D GND R OSC IN _B PAM86 15 AGN D VC M SY N C DCV VC LAMP MS_S V PVC C_ B OU T_ B BS T_ B PGND _ B OU T_ B 24 2 1 2 1 00 0uF 23 22 0.22 uF VC C 21 20 1 uF 19 1 00k 0 .1u F 0 .68 uF 1 0u F 18 17 16 15 1 uF 0.22 uF 0 .68 uF 14 22 uH 13 2 1 2 1 00 0uF 0.1u F Single-ended Configuration Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 1 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier VC C 47 0uF 10 uF 0.1u F 1 2 ON 3 SH D N MUTE ON 4 1uF R i1 5 IN + 6 Ri2 1uF 7 IN 1uF 8 9 Vol ume 10 11 VCC 12 47 0uF 10 uF OU T_A O UT_A PV CC_ A PG N D_A SH DN BST_A MU TE AVC C IN_A AVD D DG ND RO SC IN_B PAM86 15 AG N D VC M SY N C DC V VC LAMP MS_SV PV CC_ B BST_B PG N D_B OU T_B O UT_B FB 24 23 0.22uF 22 VC C 21 100 0p F 1uF 20 100 k 19 0 .1uF 10u F 18 17 1uF 16 0.22uF 15 100 0p F 14 FB 13 0.1u F BTL Configuration Block Diagram VLCAMP VCM VCLAMP BST_A IN_A Gain Adj + 2-order ERROR AMP PVCC_A + Modulation Logic _ Driver OUT_A PGND_A VCM VLCAMP BST_B PVCC_B IN_B - Gain Adj + 2-order ERROR AMP + Modulation Logic _ Driver OUT_B PGND_B VCM DCV AGND Gain Control DGND SC Detect ROSC OTP SYNC On/Off Depop OSC/RAMP MS_SV Protection Logic SHDN MUTE AVCC AVDD 5V LDO Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 2 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Pin Configuration & Marking Information TSSOP24 24 OUT_A OUT_A 1 PVCC_A 2 SHDN 3 23 PGND_A 22 BST_A 21 AVCC MUTE 4 IN_A 5 DGND 6 IN_B 7 VCM 8 DCV 9 MS_SV 10 PVCC_B 11 OUT_B 12 20 AVDD 19 ROSC 18 AGND 17 SYNC 16 VCLAMP 15 BST_B X: Internal Code Y: Year WW: Week LL: Internal Code 14 PGND_B 13 OUT_B Pin Descriptions Pin N ame I/O/P Description 1 .24 OUT_ A O H-b ridg e A out put 2 PVCC_ A P Power su pply for H-brid ge A, not co nnecte d to PV CC_ B or AVCC 3 S HDN I Shu tdown signal for IC (low=shutd own, high=operat io nal). TTL logic levels with complian ce to AVCC 4 M UTE I A logic high on t his p in disables th e outp uts. A low on this pin e nables the out puts. TTL log ic levels with co mpliance to AVCC 5 IN_A I Aud io input for chan ne l A 6 DGND P Dig ita l GND 7 IN_B I Aud io input for chan ne l B 8 VCM O Reference for a nalog ce lls 9 DCV I DC volt age setting t he g ain of the amplifier Master/Slave sele ct for d eterm in in g dire ct io n of SYNC terminal. Hig h=M aster mode , S YNC term in al is an out put; Low=Slave m ode, SY NC terminal accept s a clo ck in put. 10 M S_SV I 11 PVCC_ B P Power su pply for H-brid ge B, not co nnecte d to PV CC_ A or AVCC 1 2.13 OUT_ B O H-b ridg e B out put 14 PGND_B P Power ground for H-bridge B 15 BS T_B I/ O Boo tstrap I /O for H-b ridge B hig h-side FET Intern ally generated vo lta ge sup ply f or bootst rap. Not t o be used as a su pply o r co nnected to an y com po nent other tha n th e deco uplin g ca pacit or. 16 VCLMA P P 17 SYNC I/ O 18 A GND P 19 ROSC I/ O 20 AVDD P Ana lo g 5V Re gulated output 21 AVCC P Hig h-voltag e an alog p ower supply 22 BS T_A I/ O 23 PGND_A P Clo ck i np ut/ou tput for synchroni zing multiple cla ss-D d evic es . Directio n determ ined by MS _SV terminal. Ana lo g GND Curren t s etting resis tor for ram p g enerator Boo tstrap I /O for H-b ridge A hig h-side FET Power ground for H-bridge A Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 3 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier 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 AVCC, PVCC................-0.3 to 30V Logic Input Voltage: SHDN, MUTE........................-0.3V to AVCC+0.3V DCV, MS_SV, SYNC...............................0 to 5.5V Analog Input Voltage: IN-A,IN-B..............................................0 to 5.5V Storage Temperature.....................-65°C to 150 °C Soldering Temperature....................... 300°C,5sec Recommended Operating Conditions Supply Voltage (Vcc)...........................10V to 26V DCV Volume Control Pin.........................0V to 5V Fosc Oscillator Frequency (Rosc=100kΩ )............ .................................................. 250 to 350kHz Ta-Operating Free-air Temperature ....-40°C to 85°C Ambient Operating Temperature.........-20 °C to 85 °C Junction Temperature Rang......... .....-40°C to 160°C Ambient Temperature Range...............-40°C to 85°C Thermal Information Parameter Sym bol Package Maximum Unit Thermal Resistance (Junction to Ambient) θJ A TSSOP-24 30 °C/W Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 4 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Electrical Characteristic VCC=24V, Gain = 20dB, R L =4 Ω, T A =25°C，unless otherwise noted. PARAMETER |VOS| ICC Fosc MAX Units 10 65 mV Quiesc ent Supply Current SHDN=2V, MUTE=0V,Input AC_GND, No load 25 40 mA MUTE=2V, No load 25 40 mA Quiesc ent Supply Current in shutdown mode SHDN=0.5V, No load 5 20 uA Os cillator Frequency Rosc =100kohm 323 k Hz VCC=24V,IO=1A, TA=27ºC 220 mΩ VCC=23.5V to 24.5V -60 dB Vcc=24V, RL=4ohm, f=1kHz 14 Vcc=24V, RL=8ohm, f=1kHz 8.2 Vcc=24V, RL=4ohm, f=1kHz 17.3 Vcc=24V, RL=8ohm, f=1kHz 9.8 Vcc=24V, RL=8ohm, f=1kHz 27 Vcc=12V, RL=8ohm, f=1kHz 7 Vcc=24V, RL=8ohm, f=1kHz 35 Vcc=12V, RL=8ohm, f=1kHz 9 RL=4ohm, f=1kHz, Po=10W 0.25% RL=8ohm, f=1kHz, Po=5W 0.15% Power Supply Rejection Ratio Output Power at 1% THD+N Po(SE) Output Power at 10% THD+N Output Power at 1% THD+N Po(BTL) Output Power at 10% THD+N THD+N TYP Vi=0V, Av=36dB Rds(on) Drain-s ource on-s tate resist ance PSRR MIN Class -D output offs et voltage(measured differently ) ICC(MUT Quiesc ent Supply Current in mute E) mode ICC(SD) Test Conditions Total harmonic dis tortion + noise W W Vn Output integrated noise floor 20Hz to 22kHz, A-weighted filter, Gain=20dB -67 dBV Cs Crosstalk Po=1W, f=1kHz, Gain=20dB -60 dB Signal-to-noise ratio Max out put at THD+N<1% , f=1kHz, Gain=20dB 86 dB Thermal trip point 160 ºC Thermal hystersis 40 ºC SNR Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 5 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier DC VOLUME CONTROL VOLT AGE OF THE TOTAL_GAIN STEP VOLUME 1 2 0.10 0.17 3 0.24 4 5 0.31 0.38 -20 6 0.45 7 8 0.52 0.59 -5 -2.5 (V) VOLT AGE OF THE TOTAL _GA IN STEP VOLUME 33 34 2.34 2.41 35 2.48 36 37 2.55 2.62 19.2 38 2.69 0 39 40 2.76 2.83 20.4 21 41 42 2.9 2.97 22.2 22.8 ( dB) -60 -40 -30 -10 (V) (dB) 17.4 18 18.6 19.8 21.6 9 10 0.66 0.73 2 3 11 0.8 4 43 3.04 23.4 12 13 0.87 0.94 4.8 44 45 3.11 3.18 24.6 14 1.01 3.25 1.08 1.15 6 6.6 46 15 16 47 48 3.32 3.39 17 1.22 49 3.46 18 19 1.29 1.36 9 50 51 3.53 3.6 20 21 1.43 1.5 9.6 10.2 52 53 3.67 3.74 22 1.57 10.8 54 3.81 30 23 24 1.64 1.71 11.4 12 55 56 3.88 3.95 30.6 31.2 25 1.78 57 4.02 26 27 1.85 1.92 12.6 13.2 58 59 4.09 4.16 31.8 32.4 28 1.99 60 4.23 29 30 2.06 2.13 15.6 61 62 4.3 4.37 31 32 2.2 2.27 16.2 16.8 63 64 4.44 4.51 5.4 7.2 7.8 8.4 13.8 14.4 15 24 25.2 25.8 26.4 27 27.6 28.2 28.8 29.4 33 33.6 34.2 34.8 35.4 36 Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 6 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Typical Performance Characteristics V DD =24V,RL =8Ω ,T A =25 °C (unless otherwise noted). 1. THD Power — Single-Ended (Load=8Ω ) 2. THD Power — Single-Ended(load=4Ω ) 20 20 10 10 V DD =24V 5 2 2 V DD =18V % V DD =18V % 1 1 0.5 V DD=12V 0.5 V DD =12V 0.2 0.08 1m V DD =24V 5 0.2 2m 5m 10m 20m 50m 100m 200m W 500m 1 2 5 10 0.1 1m 20 2m 5m 10m 20m 50m 100m 200m 500m 1 2 5 10 20 W 4. Cross talk— Single-Ended 3. Frequency response — Single-Ended -3 0 T TTTTT T T TT +24 -3 5 +22 -4 0 +20 -4 5 +18 -5 0 +16 -5 5 d B g +14 A +10 Gain=20dB -6 0 d B +12 -6 5 -7 0 -7 5 +8 -8 0 +6 -8 5 Po=1W Cout=1000uF +4 +2 -9 0 -9 5 +0 20 50 100 200 500 1k 2k 5k 10k - 10 0 20 20k 50 100 20 0 50 0 5. PSRR— Single-Ended -2 0T -2 5 -3 0 T T T T T T T T 1k 2k 5k 1 0k 2 0k Hz Hz 6. THD Power — Single-Ended T 30 20 V DD =24V Vpp=200mV 10 -3 5 5 -4 0 GV =20dB -4 5 2 -5 0 1 -5 5 d B -6 0 % 0. 5 -6 5 0. 2 -7 0 -7 5 0. 1 -8 0 0 .0 5 -8 5 -9 0 0 .0 2 -9 5 -10 0 20 50 100 20 0 50 0 1k 2k 5k 1 0k 0 .0 1 10 20 k 20 50 10 0 20 0 50 0 1k 2k 5k 10 k 20 k Hz Hz Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 7 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Typical Performance Characteristics V DD =24V,RL =8Ω ,T A =25 °C (unless otherwise noted). 7. THD Power — BTL 8. Frequency response— BTL 20 +40 +38 10 +36 5 V DD =12V +34 V DD=24V +32 2 d B r V DD =18V % 1 +30 A +28 V DD =15V 0. 5 +26 Cin=1uF +24 0. 2 0. 1 10m +22 +20 20m 50m 100m 200m 500m 1 2 5 10 20 20 40 50 100 200 9. THD Frequency— BTL 1k 2k 5k 10k 20k 10. PSRR— BTL 30 -20 T T T T T T T T T T T T T 20 10 500 Hz W -25 -30 G V=20dB -35 5 -40 -45 2 -50 1 % -55 d B 0.5 -60 -65 0.2 -70 -75 0.1 -80 0. 05 -85 V DD =24V Vpp=200mV -90 0. 02 -95 0. 01 10 20 50 100 200 500 Hz 1k 2k 5k 10k -100 20 20k 50 100 200 500 Hz 1k 2k 5k 10k 20k Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 8 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Test Setup for Performance Testing PAM8615 Demo Board Load +OUT AP System One Generator Input AP Low Pass Filter GND -OUT AP System Two 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 effic iency measurement. Application Information Power and Heat Dissipation more vias on the PCB around the device if possible. Choose speakers that are able to stand large output power from the PAM8615. Otherwise, speaker may suffer damage. Volume Control A DC volume control section is integrated in PA M8 61 5, c on tro ll i ng v ia DCV and DG ND terminals. The voltage on DCV pin, determines internal amplifier gain as listed in Page6. Heat dissipation is very important when the device works in full power operation. Two factors affect the heat dissipation, the efficiency of the device that determines the dissipation power, and the thermal resistance of the package that determines the heat dissipation capability. If a resistor divider is used to fix gain of the amplifier, the DCV terminal can be directly connected to the resistor divider connected across AVDD and DGND. For fixed gain, the resistor divider values are calculated to center the voltage given in Page6. Generally, class-D amplifiers are high efficiency and need no heat sink. For high power ones that has high dissipation power, the heat sink may also not necessary if the PCB is carefully designed to achieve good heat dissipation by the PCB itself. MUTE Operation The MUTE pin is an input for controlling the output state of the PAM8615. A logic high on this pin disables the outputs and low enables the outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade. Dual-Side PCB To achieve good heat dissipation, the PCB's copper plate should be thicker than 35um and the copper plate on both sides of the PCB should be utilized for heat sink. The thermal pad on the bottom of the device should be soldered to the plate of the PCB, and via holes, usually 9 to 16, should be drilled in the PCB area under the device and deposited copper on the vias should be thick enough so that the heat can be dissipated to the other side of the plate. There should be no insulation mask on the other side of the copper plate. It is better to drill Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 9 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Shutdown Operation possible to the device's PVCC lead. To filter l o we r - f r e qu e n c y no i s e s , a l ar ge a l um i n u m electrolytic capacitor of 470µF or greater is recommended, placing near the audio power amplifier. The 10µF capacitor also serves as a local storage capacitor for supplying current during large signal transients on the amplifier outputs. The PAM8615 employs a shutdown operation mode to reduce supply current to the absolute minimum level during periods of non-use to save power. The SD input terminal should be pull high during normal operation when the amplifier is in use. Pulling SD low causes the outputs to mute and the amplifier to enter a low-current state. SD should never be left unconnected to prevent the amplifier from unpredictable operation. Selection of ROSC The switching frequency is determined by the values of components connected to ROSC (pin 19) and calculated with the following equation: For the best power-off pop performance, the amplifier should be set in shutdown mode prior to removing the power supply voltage. f osc = Internal Bias Generator Capacitor Selection The internal bias generator (VCM) provides the internal bias for the preamplifier stage. The exter nal input capa citor s and this inter nal reference allow the inputs to be biased within the o p t i m a l c o m m o n - m o d e r a n g e o f th e i n p u t preamplifiers. 0.68 ROSC 21 pF The recommended values is ROSC=100k Ω for a switching frequency of 323 kHz. BST_A and BST_B Capacitors The half H-bridge output stages use NMOS transistors only. They therefore require bootstrap capacitors for the high side of each output to turn on correctly. An at least 220nF ceramic capacitor, rated for at least 25V, must be connected from each output to its corresponding bootstrap input. Specifically, one 220nF capacitor mus t be connected from OUT_A to BST_A, and another 220nF capacitor from OUT_B to BST_B. It is recommended to use 1μF BST capacitor to replace 220nF for lower than 100Hz applications. The selection of the capacitor value on the VCM terminal is critical for achieving the best device performance. During startup or recovery from shutdown state, the VCM capacitor determines the rate at which the am plifier starts up. The startup time is not critical for the best de-pop performance since any heard pop sound is the result of the class-D output switching-on other than that of the startup time. However, at least a 0.47µF capacitor is recommended for the VCM capacitor. VCLAMP Capacitors Another function of the VCM capacitor is to bypass high frequency noise on the internal bias generator. To ensure that the maximum gate-to-source voltage for the NMOS output transistors not exceeded, two internal regulators are used to clamp the gate voltage. A 1µF capacitors must be connected from VCLAMP to ground and must be rated for at least 25V. The voltages at the VCLAMP terminals vary with VCC and may not be used to power any other circuitry. Power Supply Decoupling, CS The PAM8615 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output total harmonic distortion (THD) as low as possible. Power supply decoupling also prevents oscillations caused by long lead between the amplifier and the speaker. The optimum decoupling is achieved by using two capacitors of different types that target different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-seriesresistance (ESR) ceramic capacitor, typically 0.1µF, is recommended, placing as close as Internal Regulated 5-V Supply (AVDD) The AVDD terminal is the output of an internallygenerated 5V supply, used for the oscillator, preamplifier, and volume control circuitry. It requires a 0.1µF to 1µF capacitor, placed very close to the pin to Ground to keep the regulator stable. The regulator may not be used to power any external circuitry. Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 10 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Using low-ESR Capacitors Class-D amplifiers in the same system are switching at the slight different frequencies. When the MS/SL is low, the switching frequency is determined by the incoming square wave on the SYNC input. The SNYC becomes an input in this mode and accept a square wave from another PAM8615 configured in the master mode or from an external GPIO. (Key: MS/SL=”H”, Master Mode, MS/SL=”L”, Slave Mode) Low-ESR capacitors are recommended throughout this application section. A real (with respect to ideal) capacitor can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this resistor minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this resistance the more the real capacitor behaves as an ideal capacitor. Short-circuit Protection INL L1 1 OUT_L CB1 2 C1 The PAM8615 has short circuit protection circuitry on the outputs to prevent damage to the device when output-to-output shorts (BTL mode), outputto-GND shorts, or output-to-VCC shorts occur. Once a short-circuit is detected on the outputs, the output drive is immediately disabled. This is a latched fault and must be reset by cycling the voltage on the SD pin to a logic low and back to the logic high state for normal operation. This will clear the short-circuit flag and allow for normal operation if the short was removed. If the short was not removed, the protection circuitry will again activate. PAM8615 (Master) INR 0 1 OUT_R L2 CB2 2 C2 MS/SL SYNC Rosc 0 Rosc "H"=Master GND=Slave MS/SL SYNC Rosc 0 Rosc L3 IN+ OUT+ 1 2 C3 PAM8615 (Slave) 0 L4 IN- OUT- 1 2 Thermal Protection C4 Thermal protection on the PAM8615 prevents damage to the device when the internal die temperature exceeds 160°C. There is a ±15 degree tolerance on this trip point from device to device. Once the die temperature exceeds the set thermal point, the device enters into the shutdown state and the outputs are disabled. This is not a latched fault. The thermal fault is cleared once the temperature of the die is reduced by 40°C. The device begins normal operation at this point without external system intervention. 0 Master-Slave and SYNC Operation The MS/SL and SYNC terminals can be used to synchronize the frequency of the class-D output switching. When the MS/SL is high or left floating due to the internal pull up resistor, the switching frequency is determined by the ROSC. The SYNC becomes an output whose source/sink current is about 0.5mA, and the frequency of this output is also determined by the ROSC. And this output can be connected to another PAM8615 who is configured in the slave mode. The output switching is synchronized to avoid any beat frequencies that occur in the audio band when two Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 11 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Ordering Information PAM8615 X X X Shipping Number of Pins: 24: H PackageType TSSOP: R Part Number Package Type Stan dard Packag e PAM8615RHR TSSOP-24 3,000 Units/T ape & Reel Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 12 PAM8615 16W/32W Stereo Class-D Audio Power Amplifier Outline Dimension TSSOP-24 Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 13