MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Key Features General Description 3W Output at 10% THD with a 4Ω Load and 5V Power The MD3303 is a 3W,class-D audio amplifier with supply 64-step digital volume control. It offers low Filterless,Low Quiescent Current and low EMI THD+N,allowing it to produce high-quality sound Low THD+N reproduction .The new filterless architecture allows 64-step Digital Volume Control the device to drive the speaker directly without Superior Low Noise needing low-pass output filters which will save 30% Efficiency up to 90% system cost and 75% PCB area. Short Circuit Protection With the same numbers of external components .the Thermal Shutdown efficiency of the MD3303 is much better than class-ab Few External Components to Save Space and Cost cousins, It can extend the battery life ideal for Pb-Free Package portable applications. Applications Lcd Monitors/TV Projectors Notebook Computer Portable Speakers Portable DVD Players, Game Machines Cellular Phones/Speaker Phones 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com The MD3303 is available in SSOP-24 and SOP-16 package. MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control *The remark value are only for reference 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Pin Descriptions MD3303 Pin Numbe Pin Name 1 -OUT_L 2 SSOP24 Description MD3303 SOP16 Pin Numbe Pin Name Description Left Channel Negative Output 1 -OUT_L PGND Power GND 2 PGND 3 PGND Power GND 3 + OUT_L 4 + OUT_L Left Channel Positive Output 4 PVDD Power VDD 5 PVDD Power VDD 5 VDD Analog VDD 6 /MUTE Mute Control Input(active low),pull-up 6 INL Left Channel Input 7 VDD Analog VDD 7 VREF Internal analog reference, connect a bypass Left Channel Negative Output Power GND Left Channel Positive Output capacitor from VREF to GND 8 INL Left Channel Input 8 DN Volume down Control(active low) 9 NC No Connect 9 UP Volume up Control(active low) 10 VREF Internal analog reference, connect a bypass 10 INR Right Channel Input Analog GND capacitor from VREF to GND 11 NC No Connect 11 GND 12 NC No Connect 12 /SHDN Shutdown Control Input(active low),pull-down 13 DN Volume down Control(active low) 13 +OUT_R Right Channel Positive Output 14 UP Volume up Control(active low) 14 PGND Power GND 15 RST Volume Controller Reset (active low) 15 PVDD Power VDD 16 NC No Connect 16 -OUT_R 17 INR Right Channel Input 18 GND Analog GND 19 /SHDN Shutdown Control Input(active low),pull-up 20 PVDD Power VDD 21 +OUT_R 22 PGND Power GND 23 PGND Power GND 24 -OUT_R Right Channel Negative Output Right Channel Positive Output Right Channel Negative Output 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 at no Input Signal………………….6.0V Maximum Junction Temperature…………………..150℃ Input Voltage………………………….-0.3V to VDD+0.3V Storage Temperature………………………-65℃ to 150℃ Soldering Temperature……………………..300℃,5sec Recommended Operating Conditions Supply voltage Range………………………….2.2V to Ambient Temperature Range………………-40℃ to 85℃ 5.5V Junction Temperature RANGE……………-20℃ to 125℃ 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Thermal Information Parameter Symbol Package Maximum Unit Thermal Resistance(Junction to Ambient) θJA SSOP-24(SOP-16) 96 ℃/W Electrical Characteristic VDD =5V, Gain=18db, RL =8Ω,TA=25℃,unless 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com otherwise noted. MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Typical Operating Characteristics(TA=25) ℃ 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Typical Operating Characteristics(continued) 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Gain Setting(VDD=5V) Step Gain(dB) Step Gain(dB) Step Gain(dB) Step Gain(dB) 1 -75.0 17 4.8 33 11.2 49 17.6 2 -39.7 18 5.1 34 11.6 50 18.0 3 -34.0 19 5.5 35 12.0 51 18.4 4 -28.2 20 5.9 36 12.3 52 18.8 5 -22.4 21 6.3 37 12.7 53 19.2 6 -16.5 22 6.7 38 13.2 54 19.6 7 -10.5 23 7.1 39 13.6 55 20.0 8 -8.0 24 7.5 40 14.0 56 20.4 9 -5.5 25 7.9 41 14.4 57 20.9 10 -2.9 26 8.3 42 14.8 58 21.3 11 -0.4 27 8.7 43 15.2 59 21.7 12 1.1 28 9.1 44 15.6 60 22.1 13 2.6 29 9.6 45 16.0 61 22.5 14 3.6 30 10.0 46 16.4 62 22.9 15 4.0 31 10.4 47 16.8 63 23.4 16 4.4 32 10.7 48 17.2 64 23.8 Power on gain or gain after reset. Note: Gain could have 1dB deviation device to device. 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Application Notice 1. When MD3303 Works without filter. We must connect the speaker before turn on. Else, it will be easy to damage the chip. 2. When MD3303 works without filter,it will be best that adding a ferrite chip bead at the outgoing line of speaker in order to suppress possible electromagnetic interference. 3. The absolute maximum rating of operation voltage is 6V power regulator;even the chip can deliver 4W sine wave with a 40hm speaker,it is not recommended for long term using due to the heat dissipation. But if the input signal is a music signal, then it can work in long term since the average power output is much less than 4W. When using dry battery cell,we should notice that if the batter cell is 4 new dry batteries or alkaline batteries,even the voltage will be over 6V,it still can work safety.Since the output voltage of the 4 pack of new drybatteries will be reduced very quickly after turn on due to the internal resistance of the battery.There is no dangerous of damaging the chip when playing music or speech, even use 4 new dry batteries. To reduce the effect of the increasing of internal resistance of batter after long term discharging , it is recommended to connect a 1000uF electrolytic capacitor between the power supply and the ground. 4. Because digital volume control has big gain, we can not make input signal too high to cause the clipping of the output signal when increase volume,also it may damage the chip. 1. The AP-AUX-0025 low pass filter is necessary for every class-D amplifier measurement done by AP analyzer. 2. Two 22μH inductors are used in series with load resistor to emulate the small speaker for efficiency and quiescent current measurement. 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Application Information Maximum Gain As shown in block diagram(page 2),the MD3303 has two internal amplifiers stage. The first stage’s gain is externally configuerable, while the second stage’s is internally fixed in a fixed-gain of the first stage is set by selecting the ratio of Rf to Ri while the second stage’s gain is fixed at 2x.Consequently,the differential gain for the IC IS AVD=20*log[2*(Rf/Ri)] The MD3303 sets maximum Rf=218kΩ and minimum Ri=27kΩ, thus the maximum closed-ggain is 24dB. Digital Volume Control(DVC) The MD3303 features a digital volume control which consists of the UP,DN and RST pins ,An internal clock is used where the clock frequency value is determined from the following formula: Fclk=fosc/2 13 The oscillator frequency fosc value is 250kHz typical, with ±20% tolerance. The DVC’s clock frequency is 33Hz(cycle time 300ms)typical. Volume changes are then effected by toggling either the UP or DN pins with a logic low .After a period of 3.5 clocks pulses with either the UP or DN pins held low ,the volume will change to the next specified step, either UP or DN, and followed by a short delay .This delay decreases the longer the line is held low, eventually reaching a delay of zero, The delay allows the user to pull UP or DN terminal low once for one volume change ,or hold down to ramp several volume changes. The delay is optimally configured for push button volume control. If either the UP or DN pin remains low after the first volume transition the volume will change again ,but this time after 9.5 clock pulses. The followed transition occurs at 2 clock pulses for each volume transition. This is intended to provide the user with a volume control that pauses briefly after initial application, and then slowly increases the rate of volume change as it is continuously applied. This cycle is shown in the timing diagram shown in figure 1. There are 64 discrets gain settings ranging from +24dB maximum to -75dB minimum, Upon device power on or applied a logic low to the RST pin,the amplifier’s gain is set to a default value of -4.5dB.However, when coming out of mute mode, the MD3303 will reset back to its previous gain setting.Volume levels for each step vary and are specified in Gain Setting table on page 7. If both the UP and DN pins are held high,no volume change will occur.Trigger points for the UP and DN pins are at 70% of VDD minimum for a logic high ,and 20% of VDD maximum for a logic low.It is recommended, however, to toggle UP and DN between VDD and GND for best performance Mute Operation The MUTE pin is an input for controlling the output state of the MD3303,A logic high on this pin enables the outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade. Quiescent current is listed in the electrical characteristic table .The MUTE pin can be left floating due to the pull-up 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control internal. Shutdown operation In order to reduce power consumption while not in use, the MD3303 contains shutdown circuitry that is used to turn off the amplifier’s bias circuitry. This shutdown feature turns the amplifier off when logic low is placed on the SHDN pin. By switching the SHDN pin connected to GND, the MD3303 supply current draw will be minimized in idle mode .The SHDN pin cannot be left floating due to the pull-down internal. Power supply decoupling functions .During start-up or recovery from shutdown The MD3303 is a high performance CMOS audio amplifier mode, CBYD determines the rate at which the amplifier that requires adequate power supply decoupling to starts up.The second function is to reduce noise ensure the output THD and PSRR are as low as poooible. produced by the power supply caused by coupling into Power supply decoupling is affecting low frequency the output drive signal.This noise is from the response. Optimum decoupling is achieved by using two internal analog reference to the capacitors of different types that target different appears as degraded PSRR and THD+N. types of noise on the power supply leads.For higher Bypass capacitor(CBYP) values of 0.47 μ F to 1.0 μ F frequency transients,spikes, or digital hash on the ceramic is recommended for the best THD AND NOISE line, a good low equivalent series resistance PERFORMANCE.Increasing the bypass capacitor reduces (ESR)ceramic capacitor,typically clicking and popping noise from power on/off and 1.0μF,placed amplifier,which as close as possible to the device VDD terminal works entering and leaving shutdown. best.For filtering lower-frequency noise signals,a Under Voltage Lock-out(UVLO) larger capacitor of 10μF(ceramic)or greater placed The MD3303 incorporates circuitry designed to detect near the audio power amplifier is recommended. when the supply voltage is low.When the supply voltage Input Capacitor(Ci) drops to 1.85v or below,the MD3303 outputs are Large input capacitors are both expensive and space disable,and the device comes out of this state and hungry for portable designs. Clearly, a certain sized starts to normal functional when the supply voltage capacitor is needed to couple in low frequencies increases. without severe attenuation.But in many cases the Short Circuit Protection(SCP) speakers used in portable systems,whether internal or The MD3303 has short circuit protection circuitr on external,have little ability to reproduce signals the outputs that prevents damage to the device during below 100Hz to 150Hz.Thus,using a large input output-to-output and output-to-GND short.When a short capacitor may not increase actual system performance. circuit is detected on the outputs,the outputs are In this case,input capacitor(Ci)and input resistance disable immediately.If the short was removed,the (Ri)of the amplifier form a high-pass filter with the device activates again. corner frequency determined equation below fc=1/2TTRiCi Over Temperature Protection In addition to system cost and size,click and pop Thermal protection on the MD3303 prevents damages to performance is affected by the size of the input the device when the internal die temperature exceeds coupling capacitor, Ci A larger input coupling 150℃.There is a 15 degree tolerance on this trip point capacitor requires more charge to reach its quiescent from device to device.Once the die temperature exceeds DC voltage(nominally 1/2 VDD).This charge comes from the 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com thermal set point,the device outputs are MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control the internal circuit via the feedback and is apt to disabled.This is not a latched fault.The thermal fault create pops upon device enable.Thus,by minimizing the is cleared once the temperature of the die is reduced capacitor size based on necessary low frequency by 60℃ .This large hysteresis will prevent motor response, turn-on pops can be minimized boating sound well and the device begins normal Analog Reference Bypass Capacitor(CBYD) operation at this point with no external system The Analog Reference Bypass Capacitor(CBYD)is the most interaction. critical capacitor and serves several important A simple solution is to put an additional capacitor How to Reduce EMI(Electro Magnetic Interference) Channel specific. A tow channels amplifier has two 1000 μ F at power supply terminal for power line nutually exclusive channels and consequently must coupling if the traces from amplifier to speakers are have tow mutually exclusive output noise ground short(<20cm). traces. The layout of the MD3303 offers separate PGND Most applications require a ferrite bead filter which connections for each channel and in some cases each shows at Figure 3.The ferrite filter reduces EMI side of the bridge. Output noise grounds must tie to AROUND 1 MHz and higher.When selecting a ferrite system ground at the power in exclusively. Signal bead.choose currents for the inputs, reference. Etc need to be one with high impedance at high frequencies ,but low impedance at low frequencies. returned to quite ground. This ground only ties to the signal components and the GND pin ,GND then ties to system ground. Power Supply Line As same to the ground, VDD and each channel PVDD need to be separated and tied together at the system power supply. Recommend that all the trace could be routed PCB layout Guidelines as short and thick as possible. For the power line Grounding layout, just imagine water stream, any barricade At this stage it is paramount that we acknowledge the placed in the trace(shows in figure 4)could result in need for separate grounds. Noise currents in the the bad performance of the amplifier. output power stage need to be returned to output noise ground and nowhere else. Were these currents to circulate elsewhere, may get into the power supply. The signal ground.etc, worse yet, they may form a loop and radiate noise. Any of these instances results in Components Placement degraded amplifier performance. The logical returns The power supply decoupling capacitors need to be for the output noise currents associated with Class-D placed as close to VDD and PVDD pins as possible.The switching are the respective PGND PINS TOR EACH inputs need to be routed away from the noisy trace. CHANNEL.The switch state diagram illustrates that The VREF bypass capacitor also needs to be close to PGND isinstrumental in nearly every switch state. This the pin of IC very much. is the perfect point to which the output noise ground trace should return. Also note that output noise ground is 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com MD3303 Filterless 3W Class-D Stereo Audio Amplifier With Digital Volume Control Dimensions Millimeters Symbol Min Max A 1.350 1.750 A1 0.100 0.250 A2 1.350 1.550 B 0.330 0.510 C 0.190 0.250 D 9.800 10.000 E 3.800 4.000 E1 5.800 6.300 e 电话:0755-82709111 827091112 827091113 传真:0755-82709114 地址:深圳市福田区中航路鼎诚国际大厦南座 2805 室 网址:Http://www.YR-IC.com 1.270（TYP） L 0.400 1.270 θ 0° 8°