tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 15W/Ch STEREO CLASS-D AUDIO POWER AMPLIFIER GENERAL DESCRIPTION The TMPA420DS is a Bridge-Tied-Load (BTL) output Class-D FEATURES ♦ 15W/Ch Stereo Class-D Output audio power amplifier for driving speakers with high power ♦ Power efficiency is up to 82% efficiency. It is able to drive 4Ω, 6Ω, 8Ω or 16Ω speakers. ♦ Convenient gain control The output power can be up to 15W per channel. No external ♦ Time delay for de-pop control heat-sink is necessary. The gain of the amplifier is defined by either gain0/gain1 gain control or by input resistance. Thermal protection and ♦ Thermal Protection ♦ Output Pin Short-Circuit Protection ♦ Low Quiescent Current (10mA Typical at 12V) short-circuit protection are integrated for safety purpose. ♦ Low Current in Shutdown Mode (<1µA Typical) The internal de-pop circuitry eliminates pop noise at power-up & shutdown operations. APPLICATIONS LCD Monitors, TVs, DVD Players and Powered Speakers ♦ Separate VCC & PVCC ♦ Regulated 5-V Supply Output For best performance, please refer to http://www.taimec.com.tw/English/EVM.htm http://www.class-d.com.tw/English/EVM.htm PACKAGE for PCB layout. QFN48 available REFERENCE CIRCUIT Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 1 tai'mec TMPA420DS Preliminary ROUTN PGNDR PGNDR ROUTP ROUTP PVCCR PVCCR LOUTN PGNDL PGNDL LOUTP LOUTP PVCCL PVCCL August 15, 2007 NC ROUTN LOUTN Rev.3.0 NC PVCCR PVCCL www.class-d.com.tw PVCCR / PVCCL NC NC www.taimec.com.tw （Please email [email protected] for complete datasheet.） Tai-1 Microelectronics reserves the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers are responsible for their products and applications using Tai-1 Microelectronics components. Note that the external components or PCB layout should be designed not to generate abnormal voltages to the chip to prevent from latch up which may cause damage to the device. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 2 tai'mec TMPA420DS Preliminary www.taimec.com.tw / www.class-d.com.tw Rev.3.0 August 15, 2007 Typical Application ROUT- ROUT+ C1 C2 1uF(16V) 1uF(16V) L5 33uH L6 33uH PVCC R9 10k 22k LINP R5 22k R6 22k PHONEJACK STEREO C10 0.47nF(6.3v) R8 22k J4 1 switch S1 2 C4 1uF(6.3v) 3 C5 1uF(6.3v) 4 C11 1uF(6.3v) 5 C6 1uF(6.3v) 6 C3 1uF(6.3v) 7 C12 1uF(6.3v) 8 9 J2 SW SPST 10 J3 SW SPST 11 12 AVDD R10 120k R11 R2 330 NC PV CCR PV CCR ROU TN ROU TN PG NDR PG NDR ROU TP ROU TP PV CCR PV CCR NC RINP SD RINN RINP HFVDDR LINP LINN HFVDDL AGND GAINO GAIN1 NC NC NC NC NC AVCC NC NC AGND VDDZ AVDD HFRC AGND NC 420DS NC PV CCL PV CCL LO UTN LO UTN PG NDL PG NDL LO UTP LO UTP PV CCL PV CCL NC SD J1 PVCC U1 C9 0.47nF(6.3v) 36 35 34 33 32 31 30 29 28 AVDD 27 26 25 R12 100 + C16 C24 0.1uF(16V) 10uF(16V) C13 1uF(6.3V) C14 1uF(6.3V) 120k 13 14 15 16 17 18 19 20 21 22 23 24 R7 C23 0.1uF(16V) 0.1uF(16V) C22 48 47 46 45 44 43 42 41 40 39 38 37 PVCC PVCC C18 1000uF(25V) R3 330 VR C25 0.1uF(16v) R1 0 C26 0.1uF(16v) C19 1000uF(25V) PVCC PVCC L7 33uH L8 33uH C7 C8 1uF(16V) 1uF(16V) LOUT- Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com LOUT+ 3 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 TERMINAL FUNCTIONS TERMINAL I/O NAME DESCRIPTION PIN NO AGND 8,26,30 － Analog ground AVCC 33 － High-voltage power supply (8V to 15V) AVDD 28 I 5-V voltage HFVDDR 4 O 2.5-V Reference for convenience of single-ended inputs HFVDDL 7 O 2.5-V Reference for convenience of single-ended inputs HFRC 27 O Power up delay LINN 6 I Negative differential input for left channel LINP 5 I Positive differential input for left channel LOUTN 16,17 O Class-D negative output for left channel LOUTP 20,21 O Class-D positive output for left channel PGNDL 18,19 － Power ground for left channel PGNDR 42,43 － Power ground for right channel PVCCL 14,15,22,23 － Power supply for left channel(8V to 15V) PVCCR 38,39,46,47 － Power supply for right channel(8V to 15V) RINP 3 I Positive differential input for right channel RINN 2 I Negative differential input for right channel ROUTN 44,45 O Class-D negative output for right channel ROUTP 40,41 O Class-D positive output for right channel SD 1 I Shutdown (Low valid) GAIN0 9 I Gain0 control GAIN1 10 I Gain1 control 29 O 5-V Regulated output (25mA output) － No connection VDDZ 11,12,13,24, NC 25,31,32,34, 35, 36,37,48 ABSOLUTE MAXIMUM RATINGS Over operating free-air temperature range unless otherwise noted(1) In normal mode Supply voltage, PVCCR, PVCCL, AvCC (Iload=0) In shutdown mode Input voltage, SD Input voltage, Gain0, Gain1, LINN, LINP, RINN, RINP Continuous total power dissipation Operating free-air temperature, TA -0.3V to 17V V -0.3V to 17V V -0.3V to AVCC+0.3V V -0.3V to 5V V See package dissipation ratings 。C -20 to 85 Operating junction temperature, TJ -20 to 150 Storage temperature, Tstg -40 to 150 。C 。C (1) Stresses beyond those listed under”absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions “is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 4 tai'mec TMPA420DS Preliminary www.taimec.com.tw / www.class-d.com.tw Rev.3.0 August 15, 2007 RECOMMENDED OPERATING CONDITIONS MIN MAX UNIT Supply voltage, VCC PVCCR, PVCCL, AvCC 8 15 V High-level input voltage, V IH SD , Gain0, Gain1 2.0 Low-level input voltage, V IL High-level input current, IIH V SD , Gain0, Gain1 0.8 VCC=15V, SD =15V 100 VCC=15V, Gain0=Gain1=5V Low-level input current, IIL V uA 5 VCC=15V, SD =0V 0.5 VCC=15V, Gain0=Gain1=0V 0.5 Operating free-air temperature, TA -20 uA 。C 85 PACKAGE DISSIPATION RATINGS PACKAGE DERATING TA ≤ 25。C TA = 70。C TA = 85。C FACTOR POWER RATING POWER RATING POWER RATING QFN48(FD) 33 mW/。C 4.125W 2.64W 2.15W DC CHARACTERISTICS T A=25。C, VCC=15V, RL=8Ω speaker (unless otherwise noted) PARAMETER TEST CONDITIONS MIN LINN LINP RINN RINP AC │VOS│ Output offset voltage VDD/AVDD 5-V Regulated output IO=0 to25mA, SD =High, VCC=8V to 15V 4.5 fOSC Oscillator frequency PVCC= VCC=8-15V 250 HFVDDR/HFVDDL Half VDD reference output ICC Quiescent current (no load) ICC(SD) Supply current in shutdown mode rds(on) Drain-source on-state resistance for all outputs UNIT mV 5.5 V 350 kHz 0.5× AVDD No load SD =High, VCC= 12V 10 20 SD =High, VCC= 15V 16 30 SD =0.8V, VCC= 9V~15V 1 VCC=15V High side IO=1A, Low side 500 Total 1100 34 Gain1=High 28 Gain0=High, Gain1= Low 22 Gain0=Low, Gain1= Low 18 Gain0=High, Gain1= High 32 Gain0=Low, Gain1=High 26 Gain0=High, Gain1= Low 20 Gain0=Low, Gain1= Low 16 Gain0=High, Gain1= High 30 Gain0=Low, Gain1=High 25 Gain0=High, Gain1= Low 19 Gain0=Low, Gain1= Low 14 Gain0=High, Gain1= High 15 Input resistance of Gain0=Low, Gain1=High 30 RINN/RINP/LINN/LINP Gain0=High, Gain1= Low 60 Gain0=Low, Gain1= Low 100 Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com mA uA 600 Gain1= High Voltage Gain at Vcc=9V Zi 5.0 Gain0=Low, Voltage Gain at Vcc=12V MAX 30 grounded Gain0=High, Voltage Gain at Vcc=15V Gain TYP mΩ dB dB kΩ 5 tai'mec TMPA420DS Preliminary www.taimec.com.tw / www.class-d.com.tw Rev.3.0 August 15, 2007 AC CHARACTERISTICS T A=25。C, VCC=15V, RL=8Ω speaker (unless otherwise noted) PARAMETER TEST CONDITIONS 15V RL=4Ω RL=6Ω *PO(max) Maximum continuous output power (r.m.s) at 1kHz, (Limited by thermal condition) RL=8Ω RL=16Ω Vn SNR Crosstalk Crosstalk between outputs TYP 10 9V 6.22 15V 15 12V 9.3 9V 5.34 15V 12.7 12V 8 9V 4.58 15V 7.65 12V 4.8 9V 2.73 Maximum output at THD+N＜0.5％, f=1kHz Gain0=Gain1=high, VCC=12V, PO=1W RL=8Ω Thermal trip point Thermal hysteresis MAX UNIT 12.5 12V Output noise Signal-to-noise ratio MIN W W W W -70 dBV 85 dB -60 dB 145 。C 。C 25 *Important notice：More copper area and vias are required for high output power especially when the output power is higher than 7W×2. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 6 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 DETAILED DESCRIPTION Efficiency The output transistors of a class D amplifier act as switches. The power loss is mainly due to the turn on resistance of the output transistors when driving current to the load. As the turn on resistance is so small that the power loss is small and the power efficiency is high. With 8 ohm load the power efficiency can be better than 80%. PCB layout for power dissipation No heat sink is necessary for power dissipation. However the PCB layout should be well designed to dissipate heat for high output power. With 80% power efficiency the generated heat when driving 15 watts to the 8 ohm load is about 3.75 watts. The heat can be carried out through the thermal pad of the device to the PCB. To ensure proper dissipation of heat the PCB has to have heat path from the bottom of the device which is soldered to the PCB. The area of the metal on the PCB for heat dissipation should be big enough. It is suggested that both sides of the PCB are used for power dissipation. Shutdown The shutdown mode reduces power consumption. A LOW at shutdown pin forces the device in shutdown mode and a HIGH forces the device in normal operating mode. Shutdown mode is useful for power saving when not in use. This function is useful when other devices like earphone amplifier on the same PCB are used but class D amplifier is not necessary. Internal circuit for shutdown is shown below. HFRC（pop-less） HFRC provides a way of soft start up delay. A half_Vcc voltage detector is integrated to detect a RC charge up. The resistor of 320k ohms of the RC circuit is also integrated in the chip but the capacitor is externally hooked up. For C=1uF the half_Vcc delay is Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 7 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 1-e-t/RC=0.5 or e-t/RC=0.5 that is t = - RC In（0.5）= （320k × 1u） （0.693） = 0.22 seconds Differential input VS single ended input Differential input offers better noise immunity over single ended input. A differential input amplifier suppresses common noise and amplifies the difference voltage at the inputs. For single ended applications just tie the negative input end of the balanced input structure to ground. If external input resistors are used, the negative input has to be grounded with a series resistor of the same value as the positive input to reduce common noise. Voltage gain The voltage gain can be set through gain0/gain1 control or by external input resistors connecting to input pins. If external resistors are used they should be well matched. Well matched resistors are also required even for single ended input configuration for low noise. Suppose the external input resistors Rext are used then the voltage gain is roughly Av=750k ohms / (Rext+15k ohms) for gain0=gain1=High Where 15k ohms is the internal resistance of the input pins. For other gain0/gain1 states please refer to DC CHARACTERISTICS for different input resistance. Input filter AC coupling capacitors are required to block the DC voltage from the device. They also define the –3db frequency at the low frequency side. The –3db frequency of the low frequency side is f-3db = 1/ (2πR C) where C is the AC coupling capacitance and R is the total resistance in series with C. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 8 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 Note that R=Zin(internal resistance) + Rext(external resistance) Also note that the input resistance of RINN/RINP/LINN/LINP is 15K ohms at Gain0=Gain1=high. Please refer to DC CHARACTERISTICS for detail. In the following diagram Rext=22k ohms, Zin=15k ohms and C=C1=0.47uF. Thus the –3db frequency at the low frequency side is about 9Hz. Rinp R C1 22k 0.47uF Zin C2 Rinn R 22k 0.47nF 15k right channel C1 0.47uF Zin 15k Class-Damplifier Linp R C1 22k 0.47uF Zin C2 Linn R 22k 0.47nF leftchannel C1 0.47uF 15k Zin 15k A bypass capacitor placed in between the positive signal path and negative signal path is to attenuate the high frequencies. It defines the –3bd frequency at the high frequency side. The input filter becomes a band pass filter. The –3db frequency of the high frequency side is f–3db=1/(2πRC) where C is the bypass capacitance and R is the total resistance in parallel with C. In this example Rext=22k ohms, Zin=15k ohms and C=C2=0.47nF. Thus the –3db frequency at the high frequency side is about 19kHz. Output filter Ferrite bead filter can be used for EMI purpose. The ferrite filter reduces EMI around 1 MHz and higher（FCC and CE only test radiated emissions greater than 30 MHz）. When selecting a ferrite bead, choose one with high impedance at high frequencies, but low impedance at low frequencies. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 9 tai'mec TMPA420DS Preliminary www.taimec.com.tw / www.class-d.com.tw Rev.3.0 August 15, 2007 Use an LC output filter if there are low frequency（＜1 MHz）EMI sensitive circuits and/or there are long wires from the amplifier to the speaker. EMI is also affected by PCB layout and the placement of the surrounding components. The suggested LC values for different speaker impendence are showed in following figures for reference. Typical LC Output Filter (1) 33μH Vo+ 0.47μ F 0.1μ F 33μH Vo0.1μ F Typical LC Output Filter (2) Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 10 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 EARPHONE USE Class-D output can be used to drive earphone. However to avoid high power to overdrive earphone and to prevent human ear to accidentally be hurt, a resistor has to be put in series with the earphone speaker. Typically a resistor of 330 ohms is adequate for this purpose. Since stereo earphone can not have BTL configuration, one end of BTL signals can be used as SE (single-ended) output. Over temperature protection A temperature sensor is built in the device to detect the temperature inside the device. When a high temperature around 145oC and above is detected the switching output signals are disabled to protect the device from over temperature. Automatic recovery circuit enables the device to come back to normal operation when the internal temperature of the device is below around 120 oC. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 11 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 Over temperature protection A temperature sensor is built in the device to detect the temperature inside the device. When a high temperature around 145oC and above is detected the switching output signals are disabled to protect the device from over temperature. Automatic recovery circuit enables the device to come back to normal operation when the internal temperature of the device is below around 120oC. Over current protection A current detection circuit is built in the device to detect the switching current of the output stages of the device. It disables the device when a pulse current beyond 8 amps is detected. It protects the device when there is an accident short between outputs or between output and ground pins. It also protects the device when an abnormal low impedance is tied to the output. High current beyond the specification may potentially causes electron migration and permanently damage the device. Shutdown or power down is necessary to resolve the protection situation. There is no automatic recovery from over current protection. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 12 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw Physical Dimensions TMPA420DS Rev.3.0 August 15, 2007 ( IN MILLIMETERS) QFN48 Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 13 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA420DS Rev.3.0 August 15, 2007 IMPORTANT NOTICE Tai-1 Microelectronics Corp. reserves the right to make changes to its products and services and to discontinue any product or service without notice. Customers should obtain the latest relevant information for reference. Testing and quality control techniques are used to screen the parameters. Testing of all parameters of each product is not necessarily performed. Tai-1 Microelectronics Corp. assumes no liability for applications assistance or customer product design. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. Reproduction of information in data sheets or related documentation is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Tai-1 Microelectronics Corp. is not responsible or liable for such altered documentation. Resale of Tai-1 Microelectronics Corp. products or services with statements different from the parameters stated by Tai-1 Microelectronics Corp. for that product or service voids all express and any implied warranties. Tai-1 Microelectronics Corp. is not responsible or liable for any such statements. Copyright ©2005,Tai-1 Microelectronics Corp. Copyright ©2005,Tai-1 Microelectronics Corp. PDF created with pdfFactory trial version www.pdffactory.com 14