PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Key Features General Description n Supply Voltage Range From 2.5 V to 5.5 V n 30 Vpp Output Load Voltage From a 2.5 V Supply n Integrated Boost Converter Generates 17.5V Supply n Programmable softstart n Small Boost Converter Inductor n Selectable Gain of 18 dB, 22 dB, and 26 dB n Selectable Boost output voltage of 8V, 12V, and 17.5V n Low Shutdown Current: <1uA n Build in Thermal , OCP ,OVP,Short protection n Available in Space Saving Packages: 16-ball 1.95mmx1.95mm CSP package 16-pin QFN4x4 package The PAM8902 is a mono, Class-D audio amplifier with integrated boost convertor designed for piezo and ceramic speakers.The PAM8902 is capable of driving a ceramic/piezo speaker with 30Vpp(10.6Vrms) from a 3.6V power supply.The PAM8902's Boost converter operates at a fixed frequency of 1.5MHz , and provides a 17.5V supply with a minimum number of external components. PAM8902 features an integrated audio low pass filter that rejects high frequency noise thus improving audio fidelity. And three gain modes of 18dB, 22dB and 26dB easy for using.PAM8902 also provides thermal ,short, under and over voltage protection. T h e PA M 8 9 0 2 i s a v a i l a b l e i n a 1 6 - b a l l 1.95mmx1.95mm CSP package and 16-pin QFN4x4 package. Applications n n n n n Wireless or Cellular Handsets Por t able DVD Player Personal Digital Assistants (PDAs ) Electronic Dictionaries Digital Still Cameras Typical Application Circuit *Option(Refer to Application Information) L1 Battery 4.7μH C1 10 μF SW AVDD VOUT ENA C2 GSET 10 μF PGND1 VSET PVCC 22nF 56k COMP PAM8902 1 μF VCM 22uH OUT+ 0.1μF VIN INP 0.1 μF INN 10Ω OUTPGND2 GND Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 1 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Block Diagram Comp PVCC Vref Resistor Divider feedback SW VOUT + GM - PWM + PWM Logic And Driver + Σ ENA CS - Enable Ramp Generator PGND1 GSET Gain Vout Setting 1.5MHz Oscillator VSET AVDD Bias and Vref VCM/SS PLL 375KHz Protection Function VCM PVCC OUT+ INN Gain Adjust INP - PWM Modulator + Level Shift and H-Bridge OUT- PGND2 AGND Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 2 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Pin Configuration & Marking Information 16 Ball CSP Top View PVCC VOUT SW PGND1 A1 A2 A3 A4 OUT+ VSET COMP B1 B2 B3 OUT- GSET VCM C1 C2 C3 C4 PGND2 ENA INN INP D1 D2 D3 D4 Marking BG YW AVDD B4 AGND BG: Product Code of PAM8902 Y: Year W: Week Top View QFN 4X4 16L 16 15 14 13 VOUT 1 SW 2 VSET 3 PGND1 4 P8902 XXXYW 5 6 7 12 ENA 11 GSET 10 INN 9 INP Y: Year W: Week X: Internal Code 8 : Pin 1 Indicator Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 3 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Pin Configuration Bump(CSP) Pin NO.(QFN) A1 16 A2 1 A3 2 A4 4 B1 15 B2 3 B3 5 B4 6 C1 14 C2 11 C3 7 C4 8 D1 13 D2 12 D3 10 D4 9 Name PVCC VOUT SW PGND1 OUT+ VSET COMP AVDD OUTGSET VCM AGND PGND2 ENA INN INP Description Audio Amplifier Power Supply Boost Convertor Output Boost Convertor Switching Node Boost Convertor Power Ground Positive Differential Audio Output Boost Convertor Output Voltage Setting(8V,12V,17.5V) Boost Convertor compensation Power Supply Negative Differential Audio Output Amplifier Gain setting ( 18dB , 22dB , 26dB) Common Mode bypass Cap Analog Ground Class D Power Ground Whole chip Enable Negative Differential Audio Input Positive Differential Audio Input 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 . ...........................................6.0V Input Voltage.............................-0.3V to V DD+0.3V Storage Temperature.....................-65°C to 150 °C Maximum Junction Temperature..................150°C Soldering Temperature....................250°C,10 sec Recommended Operating Conditions Supply voltage Range........................ 2.5V to 5.5V Ambient Temperature Range............-40 °C to 85 °C Junction Temperature Range......... -40°C to 125°C Thermal Information Parameter Symbol Thermal Res istance (Junc tion to ambient) θJA Thermal Resistance (Junction to case) θJC Package Max imum CSP 90 QFN4X4-16 52 CSP 75 QFN4X4-16 30 Unit °C/W °C/W Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 4 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Electrical Characteristic T A=25 °C, V DD =3.6V,CL =1uF,Vset float, unless otherwise noted . Parameter Input voltage Quiescent Current Shutdown Current Wake-Up tim e Chip Enable Chip Disable GSET/VSET High GSET/VSET Floating GSET/VSET Low Under Voltage lockout thres hold Under Voltage lockout Hysteres is Therm al s hutdown threshold Therm al s hutdown lockout Hysteresis Symbol T est Condition Vdd EN>1.2V, VSET = High IQ EN>1.2V, VSET = Floating EN>1.2V, VSET = GND ISD EN=0V Twu EN from low to high Veh Vel Vh Vf Vl UVLO Vdd from high to low UVLOh Vdd from low to high OTP OTPh M in 2.5 Typ 30 10 5 0.1 40 M ax 5.5 48 18 12 1 1.2 0.4 Vdd Vdd-1 0.5 Vdd-0.5 1 0 2.2 0.2 150 30 Unit V mA uA mS V V V ℃ ℃ Boost Convertor Current Lim it Low Side Mosfet Rdson Boost switching frequenc y Vo1 Vo2 Vo3 Cl Rls Foscb Class D Class D Amplifier Switching Frequency Com mon mode reject ratio Ouput offset voltage Foscd CMRR Vos Output Voltage Rds on Closed-loop voltage gain Power supply reject ratio Total harmonic distortion plus noise Signal to noise ratio VSET=GND , No load VSET=NC , No load VSET=AVDD , No load Average input current Io=50m A 7.2 10.8 16 1.1 Input AC-GND Vin=+-100mV, Vdd=3.6V output offset voltage High side Rp Low side Av1 Gset=AVDD,Vo=1Vrms Av2 Gset=NC,Vo=1Vrms Av3 Gset=GND,Vo=1Vrms PSR R 200m Vpp s upply ripple at 217Hz THD+N Vo=5Vrms SNR Input AC Ground,A-weighting 225 25 21 17 8 12 17.5 0.8 0.5 1.5 8.8 13.2 19 375 60 5 1.5 0.6 26 22 18 70 0.3 90 475 1.9 V V V A Ω MHz 50 KHz dB mV Ω Ω 27 23 19 dB dB % dB Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 5 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Typical Operating Characteristics T A=25 °C, V DD=4.2V,Gain=26dB,Cin=1uF,Cload=1uF, unless otherwise noted . 1. Total Supply Current VS Output Voltage 2. Total Input Power VS Output Voltage 0 .6 160 140 0 .5 120 0 .4 100 0 .3 80 60 0 .2 40 VDD=3.6V VD D = 3.6 V 0 .1 VDD=4.2V 20 VD D = 4.2 V VDD=5.5V VD D = 5.5 V 0 0 0 2 4 6 8 10 12 0 2 4 Out put Voltage(V rms) 3. THD+N VS Frequency 8 10 12 4. THD+N VS Frequency 10 5 6 O u tp ut Vo lt ag e(V rm s) 10 VDD=3.6V 5 2 VDD=5.5V 2 Vo=2Vrms 1 Vo=2Vrms 1 Vo=4Vrms 0.5 0.5 Vo=4Vrms 0.2 0.2 0.1 0.1 0.05 0.03 20 0.05 Vo=6Vrms 50 100 200 500 1k 2k 5k 10k Vo=6Vrms 0.03 20 20k 50 100 1k 2k 5k 10k 20k Frequency(Hz) Frequency(Hz) 5. Output Voltage RMS VS Frequency 6. Output Voltage RMS VS Frequency 18 18 ΤΗD=1% Vset High 16 VDD=5.5V 14 ΤΗD=10% Vset High VDD=5.5V 14 12 12 10 10 8 8 6 VDD=4.2V 6 VDD=4.2V 4 4 VDD=3.6V 2 0 20 500 Hz Hz 16 200 50 100 200 500 1k 2k 5k 10k VDD=3.6V 2 0 20 20k Hz 50 100 200 500 1k 2k 5k 10k 20k Hz Frequency(Hz) Frequency(Hz) Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 6 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Typical Operating Characteristics T A=25 °C, V DD=5V,Gain=18dB, unless otherwise noted . 7. Output Voltage RMS VS Frequency 8. Output Voltage RMS VS Frequency 10 12 8 7 11 VDD=5.5V 9 ΤΗD=10% Vset Floating VDD=5.5V 10 ΤΗD=1% Vset Floating 9 8 6 7 5 6 VDD=4.2V 4 5 VDD=4.2V 4 3 VDD=3.6V 2 3 VDD=3.6V 2 1 0 20 1 50 100 200 500 1k 2k 5k 10k 0 20 20k 50 100 200 500 Hz Frequency(Hz) 5k 10k 20k 10. Output Voltage RMS VS Frequency 8 8 ΤΗD=1% Vset Low 2k Frequency(Hz) 9. Output Voltage RMS VS Frequency 7 1k Hz 7 VDD=5.5V 6 6 5 5 4 ΤΗD=10% Vset Low VDD=5.5V VDD=4.2V 4 VDD=4.2V 3 VDD=3.6V 3 VDD=3.6V 2 2 1 1 0 20 50 100 200 500 1k 2k 5k 10k 0 20 20k 50 100 Hz Frequency(Hz) 500 Hz 1k 2k 5k 10k 20k 9 10 Frequency(Hz) 11. Output Voltage RMS VS THD+N 12. Output Voltage RMS VS THD+N 20 20 VDD=3.6V Vset High 10 5 2 2 1 1 0.5 0.5 0.2 0.2 0 2 VDD=4.2V Vset Floating 10 5 0.1 200 4 6 8 10 12 14 0.1 16 0 1 2 3 4 5 6 7 8 V V Output Voltage RMS Output Voltage RMS Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 7 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Application Information Select Boost Convertor Output Voltage Customer can use Vset pin to set boost converor output voltage between 8V,12V and 17.5V. Vset pin configuration table as below: Vset pin configuration Connect to AVDD Floating Min AVDD - 0.5V 1V Max AVDD AVDD - 1V PVCC Voltage 17.5V 12V Audio amplifier maximum output voltage 11Vrms (Vpp=31.1V) 8Vrms(Vpp=22.6V) Connect to GND GND 0.5V 8V 5Vrms(Vpp=14.1V) Input Resistance (Ri) The input resistors (Ri=Rin+Rex) set the gain of the amplifier according to Equation 1 when anti-saturation is inactive. G=20 Log [12.8*Rf/(Rin+Rex)] (dB) Gs et Gs et=Vdd Gset=Floating Gset=GND Rin 77.4kΩ 100kΩ 122.6kΩ Rfb 122.6kΩ 100kΩ 77.4kΩ Where Rin is a 77.4K Ω internal resistor, Rex is the external input resistor,Rf is a 122.6K Ω internal resistor. Resistor matching is very important in fully differential amplifiers. The balance of the output on the reference voltage depends on matched ratios of the resistors. CMRR, PSRR, and cancellation of the second harmonic distortion diminish if resistor mismatch occurs. Therefore, it is recommended to use 1% tolerance resistors or better to keep the performance optimized. Matching is more important than ov erall tolerance. Resistor arrays with 1% matching can be used with a tolerance greater than 1%. Place the input resistors very close to the PAM8902 to limit noise injection on the high-impedance nodes. For optimal performance the gain should be set to lower. Lower gain allows the PAM8902 to operate at its best, and keeps a high voltage at the input making the inputs less susceptible to noise. In addition to these features, higher value of Ri minimizes pop noise. Input Capacitors (Ci ) In the typical application, an input capacitor, Ci, is required to allow the amplifier to bias the input signal to the proper DC level for optimum operation. In this case, Ci and the minimum input impedance Ri form is a high-pass filter with the corner frequency determined in the follow equation: fc = 1 2pRiCi It is important to consider the value of Ci as it directly affects the low frequency performance of the circuit. For example, when Ri is 150k Ω and the specification calls for a flat bass response are down to 150Hz. Equation is reconfigured as followed: 1 Ci = 2p Rifc When input resistance variation is considered, the Ci is 7nF, so one would likely choose a value of 10nF. A further consideration for this capacitor is the leakage path from the input source through the input network (Ci, Ri + Rf) to the load. This leakage current creates a DC offset voltage at the input to the amplifier that reduces useful headroom, especially in high gain applications. For this reason, a low-leakage tanta lum or ceramic capacitor is the best choice. When polarized capacitors are used, the positive side of the capacitor should face the amplifier input in most applications as the DC level is held at V DD/2, which is likely higher than the source DC level. Please note that it is important to confirm the capacitor polarity in the application. Decoupling Capacitor The PAM8902 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. The optimum decoupling is achieved by using two different types of capacitors that target on differ ent types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 8 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Application Information good low equivalent series-resistance (ESR) ceramic capacitor, typically 1 μF, is placed as close as possible to the device AVDD pin for the best operation. For filtering lower frequency noise signals , a large ceramic capacitor of 10 μF or greater placed near the AVDD supply trace is recommended. External Schottky Diode Use external schottky diode can get the best driving capability and efficiency. Since internal power diode has limited driving capability ,only in following conditions customer ca n remove the external schottky diode to reduce the cost. 1. Vset = GND or Floating and C L less than 1uF. 2. The signal frequency less than 4KHz. 3. Haptic application (50-500Hz) Shutdown operation In order to reduce power consumption while not in use, the PAM8902 contains shutdown circuitry amplifier off when a logic low is placed on the ENA pin. By switching the ENA pin connected to GND, the PAM89 02 supply current draw will be minimized in idle mode. Under Voltage Lock-out (UVLO) The PAM8902 incorporates circuitry designed to detect supply voltage. When the supply voltage dro ps to 2.2V or below, the PAM8902 goes into a state of shutdown, and the device comes out of its shutdown state and restore to normal function only when reset the power supply or ENA pin. Short Circuit Protection (SCP) The PAM8902 has short circuit protection circuitry on the outputs to prevent the device from damage when output-to-output shorted or output-to-GND shorted occurs. When a short circuit occurs, the device goes into a latch state and must be reset by cycling the voltage on the ENA pin to a logic low and then 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. Over Temperature Protection (OTP) Thermal protection on the PAM8902 prevents the device from damage when the internal die temperature exceeds 150°C. There is a 15°C tolerance on this trip point from device to device. Once the die tem perature exceeds the set point, the device will enter the shutdown state and the outp uts are disabled,in this condition both OUT+ and OUT- will become high impedance. This is not a latched fault. The thermal f ault is cleared once the temperature of the die decreased by 30°C. This large hysteresis will prevent motor boating sound well and the device begins normal operation at this point with no external system int eraction. Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 9 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Ordering Information PAM8902 X X X - P PAM Confidential Number of pins Package Type Pin Configuration Part Number Marking BG PAM8902ZER-P YW P8902 PAM8902KER-P X XXYW Package Type MOQ CSP-16L 3,000 Units/ Tape & Reel QFN4X4-16L 3,000 Units/ Tape & Reel Marking Instruction Y : Last Digital of Manufacturing Year 6: 2006 7: 2007 8: 2008 9: 2009 0: 2010 1: 2011 W : Week Code 1 2 3 4 Week code A B C D 14 15 16 17 Week code N O P Q 5 6 7 E F G 18 19 20 8 9 10 11 12 H I J K L 13 M Item 27 28 29 30 Week code A B C D R S T 31 32 33 21 22 23 24 25 U V W X Y 26 Z Item 40 41 42 43 Week code N O P Q E F G 44 45 46 R S T 34 35 36 37 38 H I J K L 47 48 49 50 51 U V W X Y 39 M 52 Z Item Item Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 10 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Outline Dimensions CSP-16 1.00 1.95 ±0.02 0.50 4 1.93 ±0.02 D Coplanarity(Flatness) Max 0.05 Units:Millimeter 0.235±0.02 (Stand off) 0.38 ±0.04 Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 11 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Outline Dimensions QFN4X4-16 Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 12 PAM8902 30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers Datasheet Revision History Date Revision Description Comment 03/03/2011 Advanced 04/07/2011 Preliminary 05/25/2011 Rev1.0 Initially releas ed 11/22/2011 Rev1.1 Add "Application Information" 12/15/2011 Rev1.2 Add "-P" to the part number in "Ordering Information" 12/22/2011 Rev1.3 Add "Pin1 Indicator" on page3 and add "Mark ing Instruction" on page10 Update "Thermal Information" and"Electrical Charateris tic" 12/28/2011 Rev1.3 Add "Coplanarity(Flatness)" value in the outline dim ension 01/05/2012 Rev1.4 Add "PSRR, THD+N, SNR" parameters to s pec Change produc t c ode from "BH" to "BG" Update "Block Diagram" Power Analog Microelectronics, Inc www.poweranalog.com 01/2012 Rev1.4 13