Preliminary Datasheet LPA2162 Filterless 2x7W Class- D Stereo Audio Amplifier With PWM/PFM mode boost convertor General Description Features The LPA2162 is a 2×7W, class-D audio amplifier with and PCB area. With high performance external N-MOS and diode，the external MOS step up convertor integrated. It offers low THD+N, allowing it to achieve high-quality Power Supply 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 LPA2162 can provide up to 7.5V stable DC voltage for amplifier so that it can display 2×7W output at 10% THD with a 4 Ω load. When it provides 5V DC voltage, it can provide 2×3W output at 10% THD with a 4 Ω load. The Integrated PWM/PFM boost convertor Low start up voltage with 1V Shut-down current:<5uA Output voltage Up to 7.5V/3A Internal Compensation Duty cycle：13%-85% Output voltage up to 7.5V Soft start delay: 2.2mS 270KHz fixed frequency switching for amplifier and 500KHz for step up convertor 2×3W Output at 10% THD with a 4 Ω Load and 5V PVDD for amplifier 2×5W Output at 1% THD with a 4 Ω Load and 7.5V PVDD for amplifier 2×6.5W Output at 10% THD with a 4 Ω Load and 7.5V PVDD for amplifier efficiency of LPA2162 is much better than that of Filterless, Low Quiescent Current and Low EMI class-AB cousins with the same numbers of external Amplifier Efficiency up to 85% Free LC filter digital modulation, direct-drive speakers Short Circuit Protection Thermal Shutdown Few External Components to Save the Space and components. The LPA2162 is available in ETSSOP-20. Order Information LPA2162 □ □ □ cost F: Pb-Free Pb-Free Package Package Type ETSSOP-20 Marking Information Applications Portable Bluetooth Speaker Cellular and Smart mobile phone Square Speaker LPA2162–00 May.-2013 Email: [email protected] Device Marking Package Shipping LPA2162 LPS ETSSOP-20 3K/REEL LPA2162 YWX Y: Y is year code. W: W is week code. X: X is series number. www.lowpowersemi.com Page 1 of 11 Preliminary Datasheet LPA2162 Typical Application Circuit Ci Ri Ci Ri 1 20 AGND PVDDR 2 19 INR OUTR+ 3 18 EXT PGNDR 4 17 VDD OUTR- 5 16 FB OUTL- 6 15 CE PGNDL 7 14 GND OUTL+ 8 13 VREF PVDDL 9 12 INL MUTE 10 11 VDD SD LPA2162–00 May.-2013 LPA2162 DIE 2 DIE 1 Email: [email protected] www.lowpowersemi.com Page 2 of 11 Preliminary Datasheet LPA2162 Functional Pin Description P in PI N N o. SD 1 Shutdown pin PVDDR 2 Right Power VDD OUTR+ 3 Right positive output PGNDR 4 Right GND OUTR- 5 Right negative output OUTL- 6 Left negative output PGNDL 7 Left power ground OUTL+ 8 Left positive output PVDDL 9 Left power VDD MUTE 10 Mute control input (active low) VDDA 11 Amplifier power supply INL 12 Left Signal input VREF 13 Reference voltage pin GND 14 Ground CE 15 Chip enable FB 16 Feedback pin VDD 17 Power supply EXT 18 Connect to Gate of external MOS INR 19 Right Signal input GNDA 20 Amplifier ground LPA2162–00 May.-2013 D ESC R I PT I O N Email: [email protected] www.lowpowersemi.com Page 3 of 11 Preliminary Datasheet LPA2162 Absolute Maximum Ratings Input voltage ------------------------------------------------------------------------------------------ -0.3V to VDD+0.3V Lead Temperature (Soldering, 5 sec.) ----------------------------------------------------------------------------300°C Storage Temperature Range ------------------------------------------------------------------------- −65°C to 150°C Operation Junction Temperature Range ------------------------------------------------------------−40°C to 125°C Operation Ambient Temperature Range---------------------------------------------------------------−40°C to 85°C Maximum Junction Temperature Range------------------------------------------------------------------------- 150°C Recommended Operating Conditions Supply Input Voltage range------------------------------------------------------------------------------------ 2.7V to 7.5V Operation Ambient Temperature Range------------------------------------------------------------------−40°C to 85°C Operation Junction Temperature Range ----------------------------------------------------------------−40°C to 125°C Thermal Information Parameter Symbol Package Maximum Unit Thermal resistance (junction to ambient θJA ETSSOP20 110 ℃/W Thermal resistance (junction to case) θJA ETSSOP20 23 ℃/W Electrical Characteristics For Amplifier (VDD = 7V, GAIN = 24dB, RL=8Ω，TA = 25° C, unless otherwise specified) Parameter Symbol Supply power VIN Output power PO Total harmonic distortion plus noise THD+N Gain GV Power supply ripple rejection PSRR LPA2162–00 May.-2013 Test Conditions THD+N=10%, f=1KHz,RL=4Ω THD+N=10%, f=1KHz,RL=8Ω VDD=5.0V,PO=0. 5W,RL=8Ω VDD=3.6V,PO=0. 5W,RL=8Ω VDD=5.0V,PO=1 W,RL=4Ω VDD=5.0V,PO=1 W,RL=4Ω VDD=7.0V,INPUT ac-grounded with CIN=0.47uF Email: [email protected] Min Typ Max Units 2.7 -- 7.5 V VDD=7.5V VDD=6.5V 6.5 5 7 VDD=5.0V 3 VDD=7.5V 4 W 0.25 f=1KHz % 0.21 0.25 f=1KHz % 0.21 f=100HZ 24 dB -79 dB www.lowpowersemi.com Page 4 of 11 Preliminary Datasheet f=1KHz crosstalk CS VDD=7V,VORMS =1V,GV=20dB f=1KHz Signal-to-noise ratio SNR VDD=7V,VORMS =1V,GV=20dB f=1KHz Output noise VN VDD=7.0V,INPUT ac-grounded with CIN=0.47uF Dynamic range DYN Eifficency η IQ Quiescen t current LPA2162 -78 dB -95 dB 80 A-weighing 100 No A-weighing 150 VDD=7.0V,THD=1 % f=1KHz 90 RL=8Ω,THD=10% f=1KHz 85 RL=4Ω,THD=10% VDD=7.5V VDD=7V VDD=5.0V f=1KHz 82 16 11 8 No load 1 μV dB % 80 75 70 mA Electrical Characteristics For Step Up Convertor (Vin=3.6V,Vout=5V,Cin=100uF,Cout=22uF//100uF,L1=4.7uH) Parameter Conditions Supply Voltage Output Voltage Range Supply Current(Shutdown) VEN=VOUT=0V,VSW=5V Supply Current VFB=0.7V Feedback Voltage Boost of LPA2162 Min Typ Units Max 2.7 5.5 V 3 7.5 V 1.2 5 uA 150 uA 1.25 1.3 V Feedback Input Current VFB=1.2V 50 nA Switching Frequency FREQ=VCC 500 KHz 90 % Maximum Duty Cycle 85 EN Input Low Voltage 0.4 EN Input High Voltage 1.4 EXT pin driver current LPA2162–00 May.-2013 V 1 Email: [email protected] V www.lowpowersemi.com A Page 5 of 11 Preliminary Datasheet LPA2162 Typical Operating Characteristic ud o ec s o +30 +20 d B r A +10 +0 B r -10 B -20 -30 20 50 100 200 500 1k 2k 5k 10k Hz Frequency response characteristic 10 1 0.1 % 0.01 0.001 0.0001 20 2.018k 4.016k 6.014k 8.012k 10.01k 12.008k 14.006k 16.004k 18.002k 20k Hz THD+N vs FREQUENCY with 3W OUTPUT 10 1 0.1 % 0.01 0.001 0.0001 20 2.018k 4.016k 6.014k 8.012k 10.01k 12.008k 14.006k 16.004k 18.002k 20k Hz THD+N vs FREQUENCY with 4W OUTPUT 10 1 0.1 % 0.01 0.001 0.0001 20 2.018k 4.016k 6.014k 8.012k 10.01k 12.008k 14.006k 16.004k 18.002k 20k Hz THD+N vs FREQUENCY with 5W OUTPUT LPA2162–00 May.-2013 Email: [email protected] www.lowpowersemi.com Page 6 of 11 20k Preliminary Datasheet LPA2162 targeting to different types of noise on the power Applications Information supply leads. For higher frequency transients, spikes, Maximum Gain or The LPA2162 has two internal amplifier stages. The equivalent-series- first stage's gain is externally configurable, while the capacitor, typically 1.0μF, works best, placing it as second stage's is internally fixed. The closed-loop close as possible to the device V DD terminal. For gain of the first stage is set by selecting the ratio of filtering lower- frequency noise signals, a large Rf to Ri while the second stage's gain is fixed at capacitor 2x.The output of amplifier 1 serves as the input to recommended, placing it near the audio power amplifier 2, thus the two amplifiers produce signals amplifier. identical in magnitude, but different in phase by 180°. Input Capacitor (C i) Consequently, the differential gain for the IC is Ci for boost. Large input capacitors are both A VD=20*log [2*(R f/Ri)] expensive and space hungry for portable designs. T h e LPA2162 sets maximum Rf= 510 k Ω±10% . Clearly, a certain sized capacitor is needed to couple Mute Operation in low frequencies without severe attenuation. But in The MUTE pin is an input for controlling the output many cases the speakers used in portable systems, state of the LPA2162. A logic low on this pin disables whether internal or external, have little ability to the outputs, and a logic high on this pin enables the reproduce signals below 100Hz to 150Hz. In the outputs. This pin may be used as a quick disable or typical application, an input capacitor Ci is required enable of the outputs without a volume fade. to allow the amplifier to bias the input signal to the Quiescent electrical proper dc level for optimum operation. Thus, using a characteristic table. The MUTE pin can be left large input capacitor may not increase actual system floating due to the internal pull-up. performance. In this case, input capacitor (C i) and Shutdown operation input resistance (R i) of the amplifier form a In order to reduce power consumption while not in high-pass filter with the corner frequency determined use, the LPA2162 contains shutdown circuitry to turn by equation below, current is listed in the 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 LPA2162 supply current draw will be minimized in idle mode. The SHDN pin can be left floating due to the internal pull-up. The LPA2162 is a high performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output THD and PSRR a low as possible. Power supply decoupling affects low response. Optimum decoupling is achieved by using two capacitors of different types LPA2162–00 May.-2013 hash of on the line, resistance 20μF fC = (ceramic) a good (ESR) or low ceramic greater is 1 2πRiCi Analog Reference Bypass Capacitor (C BYP) In addition to system cost and size, click and pop performance is affected by the size of the input coupling capacitor, Ci. A larger input coupling capacitor requires more charge to reach its quiescent Power supply decoupling frequency digital 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. The Analog Reference Bypass Capacitor (CBYP) is Email: [email protected] www.lowpowersemi.com Page 7 of 11 Preliminary Datasheet LPA2162 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. The LPA2162 incorporates circuitry designed to detect low supply voltage. When the supply voltage drops to 2.7V or below, the LPA2162 outputs are disabled, and the device comes out of this state and starts to normal function when VDD≥2.7V. Under voltage lock-out (UVLO) Most applications require ferrite bead filter as shown in above picture. The ferrite filter reduces EMI of Short Circuit Protection (SCP) The LPA2162 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. around 1 MHz and higher. When selecting a ferrite bead, choose once with high impedance at high frequencies, and low impedance at low frequencies. DC voltage setting The output voltage of boost convertor is programmed by feedback resistance and feedback voltage: Over Temperature Protection Thermal protection on the LPA2162 prevents the device from damage when the internal die temperature exceeds 140℃. There is a 15 degree VOUT = VFB ( tolerance on this trip point from device to device. R1 + 1) R2 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℃. This large hysteresis will prevent motor boating sound well and the device begins normal operation at this point without external system intervention. How to reduce EMI A simple solution is to put an additional capacitor 1000uF at power supply terminal for power line. The traces from amplifier to speakers should design as short as we can. VFB=1.25V External N-channel MOS If we want a 7.5V and 2.5Aoutput for amplifier, a 20V, 6.5A MOS with low Ohm at turn on condition is required. Lower Ohm and faster the MOS performance，the higher efficiency with circuit. Inductor Selection For a better efficiency in high switching frequency converter, the inductor selection has to use a proper core material such as ferrite core to reduce the core loss and choose low ESR wire to reduce copper loss. LPA2162–00 May.-2013 Email: [email protected] www.lowpowersemi.com Page 8 of 11 Preliminary Datasheet LPA2162 The most important point is to prevent the core saturated when handling the maximum peak current. PCB Layout notices Using a shielded inductor can minimize radiated 1, In the path of the input signal plus a 103-to-ground noise in sensitive applications. The maximum peak high-frequency filter capacitor. inductor current is the maximum input current plus 2, The power and ground and filter capacitor and the half of inductor ripple current. The calculated bypass capacitors as close to the chip's pins, peak current has to be smaller than the current remember not to put the capacitor on the back of the limitation in the electrical characteristics. A typical board, through tiny holes through the jumper even setting of the inductor ripple current is 20% to 40% of over. the maximum input current. If the selection is 40%, 3, Power, ground, and a large current signal line to the maximum peak inductor current is: go to try to rough, if you want to add vias, the number of through-holes must be at least 6. 4, AGND and AVDD should be put independently, high-power signals to avoid interference. 5, If you want to pursue as large as the effect of The minimum inductance value is derived from the following equation: power, a large selection of speakers or sound chamber with low resistance (such as 3.6Ω) speakers, or added to improve the supply voltage boost circuit. Depending on the application, the recommended inductor value is between 2.2μH to 10μH. 6, Sensitive attention to shielding the signal line, it is best to use a differential signal. Try not to interfere with the sensitive line through the signal line. 7, The position on the board under the amplifier chip must be added vents and large areas of exposed copper and tin to enhance heat dissipation. LPA2162–00 May.-2013 Email: [email protected] www.lowpowersemi.com Page 9 of 11 Preliminary Datasheet LPA2162 PCB Layout TOP VIEW BOTTOM VIEW LPA2162–00 May.-2013 Email: [email protected] www.lowpowersemi.com Page 10 of 11 Preliminary Datasheet LPA2162 Packaging Information LPA2162–00 May.-2013 Email: [email protected] www.lowpowersemi.com Page 11 of 11