tai'mec 2.7W + 0.6W x 2 TMPA221DS Preliminary www.taimec.com.tw / www.class-d.com.tw Rev.1.0 December 24, 2007 2.1 Channel CLASS-D AUDIO POWER AMPLIFIER GENERAL DESCRIPTION FEATURES The TMPA221DS is a 2.1 channel stereo & bass class-D audio ♦ 2.5V to 6V Single Supply power amplifier IC. It delivers up to 2.7W (bass) and ♦ Integrated 2.1 channel power amplifiers in one chip 0.6W(right/left channel each) into 3 ohm loads. The bass ♦ Up to 2.7W(bass)+ 0.6W(right/left Ch) at 5V, 3 ohms output is designed as BTL (Bridge-Tied-Load) for high output ♦ Up to 82% Power Efficiency power. The right & left channels are designed as SE ♦ Automatic output power control (APC) (Single-Ended). The power efficiency can be up to 82% for 8 ohm load. No external heat-sink is required. ♦ Total 4.4mA Quiescent Current at 5V ♦ Less Than 0.4uA Shutdown Current ♦ Pop-less Power-Up, Shutdown and Recovery The internal de-pop circuitry eliminates pop noise at ♦ Thermal Shutoff and Automatic Recovery power-up & shutdown operations. Automatic power gain control makes the best use of battery. ♦ Compatible with earphone application ♦ Output Pin Short-Circuit Protection (Short to Other Analog input signal is converted into digital output which drives directly the speaker. High power efficiency is Outputs, Short to VCC, Short to Ground) ♦ Differential Signal Processing Improves CMRR achieved due to digital output at the load. The audio information is embedded in PWM（Pulse Width Modulation）. Package TSSOP20 Available, pb free【RoHS】 APPLICATIONS For best performance, please refer to Multimedia application includes Cellular Phones, PDAs, http://www.taimec.com.tw/English/EVM.htm DVD/CD players, 2.1 channel audio systems, USB audio. It http://www.class-d.com.tw/English/EVM.htm is also ideal for other portable devices like Wireless Radios. for PCB layout. REFERENCE CIRCUIT（Please refer to TMPA002.APP for application） Copyright©2005, Tai-1 Microelectronics Corp. 1 tai'mec TMPA221DS Preliminary www.taimec.com.tw / 1 BO UTP 2 VDD 3 NC 4 BI N P 5 BI N N 6 LI N 7 RI N 8 NC 9 VDD 10RO UT Rev.1.0 www.class-d.com.tw December 24, 2007 20 19 V D D18 SD NB17 A V DD16 A G ND15 CA P 14 V D D13 LO UT 12 G N D11 GND BO UTN TMPA221DS （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. Typical Application J1 LS3 VO1+ VO1- PHONEJACK STEREO SPEAKER J2 L1 33uH C9 1uF(6.3V) VDD R8 LIN R7 12k JP1 12k C14 33nF(6.3V) R6 6k VR C16 1uF(6.3V) C1 C2 C3 C4 1uF(6.3V) 1uF(6.3V) 6.8nF(6.3V) 6.8nF(6.3V) R1 22k VDD R9 22k R2 0 R14 R3 330 330 C15 1nF(6.3V) C18 1nF(6.3V) C13 470uF + 1 BO UTP 2 VDD 3 NC 4 BI N P 5 BI N N 6 LI N 7 RI N 8 NC 9 VDD 10RO UT 20 19 V D D18 SD NB17 A V DD16 A G ND15 CA P 14 V D D13 LO UT 12 G N D11 221DS(FD) C17 1uF(6.3V) C10 1uF(6.3V) 33uH SDN 100 R5 C6 4.7uF(6.3V) R10 S1 LS1 10K switch L3 R4 3k R11 3k VOR+ SPEAKER C8 1uF(6.3V) + 33uH C19 220uF(6.3V) L4 33uH C11 VDD L2 GND BO UTN + RIN + C12 1uF(6.3V) C20 220uF(6.3V) R12 3k 1uF(6.3V) R13 3k LS2 VOL+ SPEAKER VDD Copyright©2005, Tai-1 Microelectronics Corp. 2 tai'mec TMPA221DS Preliminary www.taimec.com.tw / Rev.1.0 www.class-d.com.tw December 24, 2007 ABSOLUTE MAXIMUM RATINGS Over operating free-air temperature range unless otherwise noted(1) Supply voltage, VDD, AVDD In normal mode -0.3V to 6V V In shutdown mode -0.3V to 7V V -0.3V to VDD+0.3V V Input voltage, VI Continuous total power dissipation See package dissipation ratings 。C -20 to 85 Operating free-air temperature, TA 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. RECOMMENDED OPERATING CONDITONS MIN Supply voltage, VDD, AVDD NOM MAX UNIT 2.5 6 V V High-level input voltage, VIH SDNB 2 VDD Low-level input voltage, VIL SDNB 0 0.8 V 85 。C Operating free-air temperature, TA -20 PACKAGE DISSIPATION RATINGS PACKAGE TSSOP20 DERATING TA ≤ 25。C TA = 70。C TA = 85。C FACTOR POWER RATING POWER RATING POWER RATING 8.73 mW/。C 1.09W 698mW 567mW ELECTRICAL CHARACTERISTICS TA=25。C (unless otherwise noted) PARAMETER │VOS│ PSRR Output offset voltage TEST CONDITIONS (measured differentially) Power supply rejection ratio -75 -55 dB -55 -50 dB VDD=AVDD=2.5V to 5.5V, High-level input current │IIL│ Low-level input current IQ Quiescent current (total) VDD=AVDD=5V, no load Shutdown current (total) V( SDN )=0.8V, VDD=AVDD=2.5V to 5.5V Static output resistance(SE) VIC=1Vpp, RL=8Ω VDD=AVDD=5.5V, mV 30 VI=5.8V (SDNB) VDD=AVDD=5.5V, µA 1 µA 4.4 6 mA 0.4 1 µA VI=-0.3V (SDNB) 790 VDD=AVDD=5.5V mΩ 550 f(sw) Switching frequency VDD=AVDD=2.5V to 5.5V 230 280 330 *Av Voltage Gain(BTL and SE) VDD=AVDD=2.5V to 5.5V, RL=8Ω 12 16 20 RSDN Resistance from shutdown to GND V(SDNB)=5V Copyright©2005, Tai-1 Microelectronics Corp. UNIT VDD=AVDD=2.5V to 5.5V │IIH│ rDS(on) MAX 25 Common mode rejection ratio Static output resistance(BTL) TYP VI=0V,AV=2, VDD=AVDD=2.5V to 5.5V CMRR IQ (SD) MIN 200 kHz V V kΩ 3 tai'mec ZI TMPA221DS Preliminary www.taimec.com.tw Input impedance / Rev.1.0 www.class-d.com.tw RINN,RINP,LINN,LINP December 24, 2007 kΩ 15 *The gain of the amplifier is determined by, for VDD=VDDA =2.5V to 5.5V Gain = 320kohms Ri + 15kohms where Ri is the external serial resistance at the input pin. OPERATING CHARACTERISTICS TA=25。C, RL=8Ω speaker (unless otherwise noted) PARAMETER TEST CONDITIONS Output power (SE output) VDD=AVDD=5V. PO THD+N=10%, Output power (bass) f=1kHz Total harmonic distortion plus noise (SE output) VDD=AVDD=5V, THD+N Total harmonic distortion plus noise f=1kHz (bass) MIN TYP MAX RL=4Ω 0.6 RL=8Ω 1.5 RL=4Ω 2.3 RL=3Ω 2.7 PO=0.6W, RL=4Ω, 0.8 PO=0.85W, RL=8Ω, 0.55 PO=1.3W, RL=4Ω, 0.55 PO=1.5W, RL=3Ω, 0.64 UNIT W % SNR Signal-to-noise ratio VDD=AVDD=5V, PO=1W, RL=8Ω 95 dB Crosstalk Crosstalk between outputs VDD=AVDD=5V, PO=1W RL=8Ω -68 dB TERMINAL FUNCTIONS TERMINAL I/O NAME AGND DESCRIPTION PIN NO 15 - Analog ground AVDD 16 - Analog Power supply CAP 14 I Capacitance for power up delay GND 11,20 - Digital ground BINN 5 I Negative input of bass BINP 4 I Positive input of bass BOUTN 19 O Negative output of bass BOUTP 1 O Positive output of bass NC 3,8 - No Connection LIN 6 I Input of left channel RIN 7 I Input of right channel LOUT 12 O Output of left channel ROUT 10 O Output of right channel SDNB 17 I Shutdown terminal (LOW active) 2,9,13,18 - Digital Power supply VDD Copyright©2005, Tai-1 Microelectronics Corp. 4 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA221DS Rev.1.0 December 24, 2007 TYPICAL CHARACTERISTICS Note 1. Input coupling 1µF capacitors are used for all measurements. 2. Differential inputs are applied for BTL output. 3. Balanced LC filter is used for THD+N measurement and power efficiency measurement. 4. Characteristic frequency of the LC filter is set 41KHz unless otherwise specified. Copyright©2005, Tai-1 Microelectronics Corp. 5 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA221DS Rev.1.0 December 24, 2007 APPLICATION INFORMATION Figure.1 Differential Bass Input Figure.2 Single-ended Bass Input Copyright©2005, Tai-1 Microelectronics Corp. 6 tai'mec Preliminary www.taimec.com.tw / TMPA221DS www.class-d.com.tw Rev.1.0 December 24, 2007 Input Resistors and Gain The gain of the amplifier is determined by, for VDD=VDDA =2.5V to 5.5V Gain = 320kohms where Ri is the external serial resistance at the input pin. Ri + 15kohms Note：Please refer to document 010 APP for more application examples. Copyright©2005, Tai-1 Microelectronics Corp. 7 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA221DS Rev.1.0 December 24, 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 82%. 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. Pop-less A soft start capacitor can be added to the CAP pin. This capacitor introduces delay for the internal circuit to be stable before driving the load. The pop or click noise when power up/down or switching in between shutdown mode can be thus eliminated. The delay time is proportional to the value of the capacitance. It is about 500ms for a capacitor of 1uF at 5v. CAP Cap provides a way of soft startup delay. A 5uA current source and a half_Vcc detector are integrated in the chip. The charged capacitor is externally hooked up. For C=1uF the half_Vcc delay is T = CV / I = （1uF × 2.5V）/ 5uA = 0.5 seconds Copyright©2005, Tai-1 Microelectronics Corp. 8 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA221DS Rev.1.0 December 24, 2007 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. Automatic output Power Control (APC) The voltage gain is self adjusted in the chip over voltage range. This means that, regardless supply voltage change, the output power keeps about the same for a given input level from VDD=5.5v to 2.5v. It allows the best use of the battery. Voltage gain The voltage gain is defined in the table on page 3. For lower voltage gain one can add external input resistors to input pins. If external resistors are used they should be well matched. Well matched input resistors are also required even for single-ended input configuration for low noise. If band pass filters are used for frequency separation please refer to following discussion. Band pass filter for frequency separation of bass and R/L channels For best sound effect the frequency of bass and R/L channels has to be separated. The bass channel amplifies the lower frequencies while the R/L channels amplify the higher frequencies. The power is saved not to drive bass speaker with high frequencies and not to drive R/L channel speakers with low frequencies. The noise level can be reduced as well. Typically the frequency boundary of bass and R/L channels is set 500 Hz and the output power of bass is set around 3~5 times of the R/L channels. Note that different applications may have different requirement for these values. Please refer to EVM documentation if the separation frequency is Copyright©2005, Tai-1 Microelectronics Corp. 9 tai'mec TMPA221DS Preliminary www.taimec.com.tw / www.class-d.com.tw Rev.1.0 December 24, 2007 200 Hz instead. Bass channel filter If the audio source is stereo (right channel signal and left channel signal) one can generate audio source for bass amplifier by mixing right and left signals and in the mean time filter out frequencies above 500 Hz. A typical application is shown below. Note that Zin=15k ohms is the internal resistance of the class-D amplifier when gain0=gain1=High. Rin R1 12k Lin R1 Cin 12k 0.47uF (R1)/2 12k//12k C1 37nF Cin 0.47uF 15k Zin Class-D amplifier 15k Zin The -3dB frequency at high frequency corner is f-3dB = 1/ (2πR C) where R=2(Zin // (R1)/2) and C=C1. With specified values f-3dB = 500Hz. The -3dB frequency at low frequency corner is calculated as f-3dB = 1/ (2πR C) where R=Zin + (R1)/2 and C=Cin. With specified values f-3dB = 16Hz. Right and Left channel filters To block frequencies below 500Hz, a typical application is shown below. Rin Lin R1 C1 22k R1 22k C2 8.6nF 0.9nF C1 Zin C2 8.6nF 0.9nF Zin 15k Class-D amplifier 15k The -3dB frequency at low frequency corner is f-3dB = 1/ (2πR C) where R=Zin + R1 and C=C1. With specified values f-3dB = 500Hz. Copyright©2005, Tai-1 Microelectronics Corp. 10 tai'mec TMPA221DS Preliminary www.taimec.com.tw / Rev.1.0 www.class-d.com.tw December 24, 2007 The -3dB frequency at high frequency corner is f-3dB = 1/ (2πR C) where R=Zin // R1 and C=C2. With specified values f-3dB = 20kHz. Note that if gain0 and gain1 are set at different states the internal input resistance is changed accordingly. Please refer to DC CHARACTERISTICS for detail. As such the filters should be redesigned to meet the 500 Hz frequency boundary. Power ratio of bass channel and right/left channels The output power ratio of bass to R/L channels is normally set 3~5. However different music has different stress in different frequency range. It becomes difficult to define a fix voltage gain for different applications and to maintain the requirement of bass to R/L ratio. A convenient way of controlling the ratio is to make bass adjustable relative to R/L channels. An easier way is to use VR as shown below. Rin VR R1 12k Lin VR R1 12k Cin BINP 0.47uF Cin 6k Zin BINN 0.47uF Zin Bass amplifier Another way is to use frequency synthesizer to preset voltage gain for different frequency range for particular music content. For simply applications an example is given below to show 3X ratio between bass output power and R/L output power. For Vcc=15v and 8ohm load the voltage gain of the bass channel is around 32. If the power ratio is 3 then the voltage ratio is 3 =1.732 and the gain of the R/L channel is 18.5. The voltage gain of the R/L channels is roughly defined as (750k ohms)/(Ri+15k ohms) Copyright©2005, Tai-1 Microelectronics Corp. 11 tai'mec Preliminary www.taimec.com.tw / TMPA221DS www.class-d.com.tw Rev.1.0 December 24, 2007 resulting Ri= 25.5k ohms. To meet the -3dB frequency of the R/L channels which is 500Hz, the filter capacitance should be adjusted to C= 1/(2π x (25.5k+15k ohms) x 500Hz) = 7.86nF. For higher output power one can consider to use 4 ohm speaker for bass and 8 ohm speakers for R/L channels. Suppose the power ratio is set 5X, then the voltage ratio is 5 / 2 =1.58. For Vcc=15v and 4ohm load the voltage gain of the bass channel is around 30. Thus the gain of the R/L channel is 19. The voltage gain of the R/L channels is defined as (750k ohms)/(Ri+15k ohms) resulting Ri= 24.5kohms . To meet the -3dB frequency of the R/L channels which is 500Hz, the filter capacitance should be adjusted to C= 1/(2π x (24.5+15k ohms) x 500) = 8nF. Note that the formula for voltage gain varies with supply voltage and loading. But the procedure is to find out the value of Ri before the capacitance is determined. Output coupling capacitor The speaker of the bass channel is tied as BTL. There is no need to have an output capacitor at the output end. But for right and left channels coupling capacitors are required to block DC from the speakers. Since the right and left channels do not amplify frequencies below 500Hz the output coupling capacitance does not have to be big. One can choose the -3dB frequency of the output coupling stage to be 200Hz, not too high to attenuate voltage at 500Hz, then the coupling capacitance is C= 1/(2πx 8 ohm x 200Hz) =100uF for 8 ohm load. or C= 1/(2πx 4 ohm x 200Hz) =200uF for 4 ohm load. Copyright©2005, Tai-1 Microelectronics Corp. 12 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA221DS Rev.1.0 December 24, 2007 Input filter In case band pass filter for frequency separation of bass and R/L channels is not used, the AC coupling capacitors are still 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. Note that R=Zin(internal resistance) + Rext(external resistance) Also note that the input resistance of BINN/BINP/LIN/RIN is 15K ohms at Gain0=Gain1=high. Please refer to DC CHARACTERISTICS for detail. 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. 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) Copyright©2005, Tai-1 Microelectronics Corp. 13 tai'mec TMPA221DS Preliminary www.taimec.com.tw / www.class-d.com.tw Rev.1.0 December 24, 2007 33μH Vo+ 0.47µ F 0.1µ F 33μH Vo0.1µ F Typical LC Output Filter (2) EARPHONE APPLICATION 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 by loud noise, a resistor has to be put in series with the earphone speaker. Typically a resistor of 330 ohms is adequate for this purpose. Copyright©2005, Tai-1 Microelectronics Corp. 14 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA221DS Rev.1.0 December 24, 2007 Over temperature protection A temperature sensor is built in the device to detect the temperature inside the device. When a high temperature around 145 oC 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. 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 the current is beyond about 3.5amps. It protects the device when there is an accident short between outputs or between output and power/gnd 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. 15 tai'mec TMPA221DS Preliminary www.taimec.com.tw / Rev.1.0 www.class-d.com.tw Physical Dimensions December 24, 2007 (IN MILLIMETERS) ± 7.72 TYP 4.16 TYP (1.78 TYP) 0.42 TYP 0.65 TYP LAND PATTERN TSSOP20 Copyright©2005, Tai-1 Microelectronics Corp. 16 tai'mec Preliminary www.taimec.com.tw / www.class-d.com.tw TMPA221DS Rev.1.0 December 24, 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. 17