SA7347 4-CH AUDIO POWER AMPLIFIER(8W X4) DESCRIPTION SA7347 is a four channel audio amplifier including two non inverted amplifiers and two inverted amplifiers, so it can be conveniently applied in Bridge-Tied Load (BTL) mode. Built-in protection circuit based on multiple temperature measurements inside SA7347 makes it possible for all supply voltages and load conditions to export maximum power. FEATURES * Soft clip HSIP-15 * Standby and mute mode * No on/off switching plops * High supply voltage ripple rejection * Thermally protected * Outputs short circuit protected to ground, supply and across ORDERING INFORMATION the load Device SA7347 APPLICATIONS Package HSIP-15 * Television, PC speakers and mini stereo system, etc BLOCK DIAGRAM + + + - + - + + HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2007.07.27 Page 1 of 9 SA7347 ABSOLUTE MAXIMUM RATING (Tamb=25°C) Characteristics Symbol Condition Unit -0.3 ~ +22 V Supply Voltage VCC Input Voltage VIN -0.3 ~ VCC + 0.3 V Repetitive Peak Output Current IORM 4 A Storage Temperature Range Tstg -55 ~ +150 °C Ambient Temperature Range Tamb -40 ~ +85 °C Ptot 69 W 17 V Total Power Dissipation Operating Rating non-operating Supply Voltage to Guarantee Short-circuit Protection VCC(SC) Thermal Resistance From Junction to Ambient Rth(j-a) In free air 40 °C/W Thermal Resistance From Junction to Case Rth(j-c) All channels driven 1.3 °C/W ELECTRICAL CHARACTERISTICS (Unless otherwise stated, VCC=15V, RL(SE)=4 , RL(BTL)=8 , f=1kHz, Vstby=VCC, Tamb=25°C) Characteristics Quiescent Supply Current Symbol Min. Typ. Max. Unit -- 100 145 mA Istby -- -- 1 mA DC Output Voltage VO -- 6.9 -- V Differential Output Voltage Offset VOUT BTL(*) -- -- 170 mV play VCC/2+3 -- VCC mute 4.5 -- VCC/2+2 standby 0 -- 0.8 VCC/2+2<Vstby< VCC -- -- 20 THD=10%, BTL, RL=4 -- 22 -- SE RL=3 -- 8 -- SE RL=4 -- 6 -- BTL RL=6 -- 17 -- BTL RL=8 -- 13 -- SE RL=3 -- 7 -- SE RL=4 -- 5 -- BTL RL=6 -- 14 -- Standby Supply Current Select Voltage on Pin STBY Select Current on Pin STBY Icq Test condition RL= Vstby Ibias THD=10% Output power PO THD=1% Total Harmonic Distortion THD Voltage Gain Gv Input Impedance Zin Noise Output Voltage PO=1W Vn(o) V µA W BTL RL=8 -- 10 -- SE -- 0.1 0.5 BTL -- 0.05 0.5 SE 25 26 27 BTL 31 32 33 SE 40 60 -- BTL 20 30 -- SE -- 150 -- BTL -- 200 -- % dB µV (To be continued) HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2007.07.27 Page 2 of 9 SA7347 (Continued) Characteristics Symbol Test condition frip=1kHz(**) Supply Voltage Ripple Rejection SVRR Vo(mute) Channel Separation CS Channel Balance CB (*) (**) VOUT = | VOUT VOUT Typ. Max. -- 60 BTL -- 65 -- 60 BTL -- 65 ----- SE -- -- 150 BTL -- -- 250 SE 50 60 -- BTL 50 65 -- SE -- -- 1 BTL -- -- 1 frip=100Hz~ SE 20kHz(**) Output Voltage in Mute Mode Min. SE Rsource=0 Unit dB dB µV dB dB | Supply voltage ripple rejection is measured at the output, with a source impedance Rsource = 0 at the input and with a frequency range from 20 Hz to 22 KHz. The ripple voltage is a sine wave with a frequency fripple and an amplitude of 300 mVrms, which is applied to the positive supply rail. Pin configurations Pin descriptions Pin No. Pin Name Description 1 OUT1+ non inverted loudspeaker output of channel 1 2 VCC1 supply voltage channels 1 and 2 3 OUT2- inverted loudspeaker output of channel 2 4 IN2 5 SGND 6 IN1 input channel 1 7 IN3 input channel 3 8 GND power ground 9 STBY mode selection input: standby, mute and play 10 SVR half supply voltage ripple rejection 11 IN4 input channel 4 12 CIV common input voltage ripple rejection 13 OUT3- inverted loudspeaker output of channel 3 14 VCC2 supply voltage channels 1 and 2 15 OUT4+ HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn input channel 2 signal ground non inverted loudspeaker output of channel 4 REV:1.1 2007.07.27 Page 3 of 9 SA7347 FUNCTION DESCRIPTION Input configuration The formula of the input cut-off frequency is: fi(cut−off) = 1 2π (Ri × Ci ) For SE application Rin = 60k fi(cut −off) = and Cin = 220nF: 1 2π (60 × 10 3 × 220 × 10 9 = 12Hz ) For BTL application Rin = 30k and Cin = 470nF: fi(cut −off) = 1 2π (30 × 10 3 × 470 × 10 9 = 11Hz ) Because of high input impedance, large capacitor values for the inputs are not necessary. The smaller input capacitor values help to reduce the switch on delay during charging of the capacitors. This results in a good low frequency response and good switch on behavior. BTL application Using the SA7347 as a BTL amplifier offers the following advantages: Ø Low peak value of the supply current Ø Ripple frequency on the supply voltage is twice the signal frequency Ø Good low frequency performance Ø No expensive DC-blocking capacitor Mode selection By changing properly DC voltage of pin STBY, SA7347 has follow functional modes which can be selected for all channels. Ø 0 < STBY < 0.8V: The current consumption is very low and the outputs are floating. Ø 4.5V < STBY < VCC/2+2V: The amplifier is DC biased, but no audio output. This allows the input coupling capacitors to be charged to avoid pop-noise. Ø VCC/2+3V < STBY < VCC: The amplifier is operating normally. Supply voltage ripple rejection The Supply Voltage Ripple Rejection (SVRR) is measured with an electrolytic capacitor of 150 F on pin SVR. A larger capacitor value on pin SVR improves the ripple rejection behavior at the lower frequencies. Built-in protection circuits As mentioned above, SA7347 has a protection circuit based on multiple temperature measurements: one measures local temperature of the power stages and another measure the global chip temperature. This HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2007.07.27 Page 4 of 9 SA7347 protection circuit will start to switch off the bias of channel when local temperature reaches approximately 185°C or global temperature reaches approximately 150°C. As a result, there is low dissipating in the chip. It starts operating again when the chip temperature drop to same value below the die temperature. But if the temperature again begins to rise, the SA7347 shuts down again. The process will not stop until the local temperature is under 185°C and the global temperature is under 150°C. This protects the SA7347 against shorts to ground, to the supply voltage and across the load, and against too high chip temperatures. However, not that there are abnormal events as shorts to ground, to the supply voltage and across the load in the chip, the protection circuit should start-up. In fact, just as much as the temperature does not exceed the critical level, the protection circuit will not operate. Power Dissipation and Heat Sinking Proper heat sinking is necessary to ensure that SA7347 will function correctly under all operating conditions. A heat sink that is too small will cause the die to heat excessively and will result in a degraded output signal as the thermal protection circuitry begins to operate. In order to determine the appropriate heat sink for a given application, the power dissipation of the SA7347 in that application must be known. When the load is resistive, the maximum average power that the IC will be required to dissipate is approximately: PD(MAX)=4*VS2/(2π2RL)+PQ Where VS is the total power supply voltage across the SA7347, RL is the load resistance; PQ is the quiescent power dissipation of the amplifier. The above equation is only an approximation which assumes an “ideal”class B output stage and constant power dissipation in all other parts of the circuit. As an example, if the SA7347 is operated on a 15V power supply with a resistive load of 4Ω, it can develop up to 13.5W of internal power dissipation. If the die temperature is to remain below 150°C for ambient temperatures up to 60°C, the total junction-to-ambient thermal resistance must be less than: (150°C 60°C)/13.5W 6.7°C /W Using Rth(j-c) = 1.3°C /W, the sum of the case-to-heat-sink interface thermal resistance and the heat-sink-toambient thermal resistance must be less than 5.4°C/W. The case-to-heat-sink thermal resistance of the HSIP-15 package varies with the mounting method used. A metal-to-metal interface will be about 1°C /W if lubricated, and about 1.5°C /W if dry. 6.7°C /W-1.3°C /W-1°C /W 4.4°C /W The thermal requirements can become more difficult when an amplifier is driving a reactive load. For a given magnitude of load impedance, a higher degree of reactance will cause a higher level of power dissipation within the amplifier. As a general rule, the power dissipation of an amplifier driving a 60º reactive load (usually considered to be a worst-case loudspeaker load) will be roughly that of the same amplifier driving the resistive part of that load. For example, a loudspeaker may at some frequency have an impedance with a magnitude of 8Ω and a phase angle of 60º. The real part of this load will then be 4Ω, and the amplifier power dissipation will roughly follow the curve of power dissipation with a 4Ω load. HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2007.07.27 Page 5 of 9 SA7347 TYPICAL APPLICATION CIRCUIT HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2007.07.27 Page 6 of 9 SA7347 PC BOARD AND COMPINENTS LAYOUT OF TYPICAL APPLICATION CIRCUIT RECOMMENDED APPLICATION VALUE OF DEVICE Next table shows the recommended value corresponding to the components in the typical application circuit. COMPONENTS RECOMMENDED VALUE CS1 1000µF CS2 100nF Cb1 22µF Common input voltage decoupling Cb2 150µF Half supply voltage decoupling 220nF Input AC coupling capacitor(SE) Ci3 470nF Input AC coupling capacitor(BTL) CO1 470µF Output AC coupling capacitor R1 51KΩ R2 100KΩ R3 51KΩ Dz 7.5V Ci1 Ci2 PURPOSE Supply voltage filtering and bypassing STBY controller HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2007.07.27 Page 7 of 9 SA7347 PACKAGE OUTLINE HSIP-15 HANGZHOU MICROELECTRONICS CO.,LTD Http: www.silan.com.cn UNIT: mm REV:1.1 2007.07.27 Page 8 of 9