Ordering number : EN5715A LA4725 Monolithic Linear IC 2-channel 30W BTL Audio Amplifier http://onsemi.com Overview The LA4725 is a 2-channel BTL audio power amplifier IC for Car audio. It was designed for the best possible audio quality and features an extended low band roll-off frequency provided by a newly-developed NF circuit that does not require an external capacitor. Furthermore, crosstalk, which can cause muddiness in the audio output, has been significantly reduced by both circuit and wiring pattern improvements. Thus this amplifier can provide powerful lows and clear highs. Features • Total output (EIAJ power): 30W+30W (at VCC = 14.4V, RL = 4Ω, THD = 30%) • High-fidelity design (fL < 10Hz, fH = 130kHz) • Extremely low impulse noise levels • An arbitrary amplifier startup time can be set up with external components • built-in standby switch circuit • Full complement of built-in protection circuits (includes circuits that protect against shorting to VCC, shorting to ground, load shorting, over-voltages and excessive temperatures) Specifications Maximum Ratings at Ta = 25°C Parameter Symbol Maximum supply voltage VCC max No signal Conditions Ratings 18 Unit Surge supply voltage VCC surge t ≤ 0.2s, Giant pulse one-shot 50 V Maximum output current IO peak Per channel 3.0 A Allowable power dissipation Pd max With a infinite heat sink 32 W Operating temperature Topr -35 to +85 °C Storage temperature Tstg -40 to +150 °C V Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. Semiconductor Components Industries, LLC, 2013 May, 2013 40109 MS JK 20090313-S00003 No.5715-1/8 LA4725 Operating Conditions at Ta = 25°C Parameter Symbol Recommended supply voltage VCC Allowable operating supply voltage VCC op Recommended load resistance RL Conditions Ratings Unit 13.2 V 9 to 16 V 4 Ω Note : With VCC, RL, and the output level in ranges such that the Pd max for the heat sink used is not exceeded. Electrical Characteristics at Ta = 25°C, VCC = 13.2V, RL = 4Ω, f = 1kHz, Rg = 600Ω Ratings Parameter Symbol Conditions min Quiescent current ICCO Rg = 0 Standby mode current drain Ist Standby mode (amplifier off), with no power typ 70 Unit max 125 250 mA 10 60 µA 40 42 dB 0.06 0.2 supply capacitor. Voltage gain VG VO = 0dBm Total harmonic distortion THD PO = 2W Output power PO1 THD = 10% PO2 PO3 VN offset Rg = 0 Output offset voltage 38 13 % 17 W THD = 10%, VCC = 14.4V 20 W THD = 30%, VCC = 14.4V 30 -300 W +300 mV 0.5 mV Output noise voltage VNO Rg = 0, BPF = 20Hz to 20kHz Ripple rejection ratio SVRR Rg = 0, VR = 0dBm, fR = 100Hz 40 0.1 50 dB Channel separation CHsep Rg = 10kΩ, VO = 0dBm 50 60 dB Input resistance Ri 21 30 Standby pin applied voltage VST Amplifier on 2.5 39 kΩ VCC V (applied through an external 10kΩ resistor) Package Dimensions unit : mm (typ) 3113B 26.8 HEAT SPREADER (20.0) 4.0 7.8 14.5MAX 1 (1.83) 5.2 4.6 7.0 (11.8) (8.4) (R1.7) 14 1.78 0.5 0.8 0.4 1.6 2.2 Allowable power dissipation, Pd max -- W 35 32.5 Pd max -- Ta Infinite heat sink AI heat sink Mounting torque 39N • cm Flat washer Silicone grease applied 30 25 20.83 20 15 13.9 10.4 10 5 3.1 0 -40 θf = 3°C/W θf = 4°C/W θjc = 2°C/W θf = 7°C/W θf = 10°C/W Νο Fin -20 0 20 40 60 80 100 120 140 160 Ambient temperature, Ta -- °C SANYO : SIP14HZ No.5715-2/8 LA4725 Block Diagram C2 100μF/25V + C5 14 2 OUTPUT PIN TO VCC SHORT PROTECTOR PREDRIVER PRE GND 3 R1 ON 10KΩ OFF POWER GND1 LOAD SHORT PROTECTOR IN 11 POWER STANDBY SW THERMAL SHUT DOWN 9 POWER IN2 + 6 + 2.2μF 25V − LOAD SHORT PROTECTOR IN PREDRIVER + POWER GND2 0.1μF 10 8 POWER ñ -OUT2 C8** RL 4Ω R4 R5 C9** +OUT2 + OUTPUT PIN TO VCC SHORT PROTECTOR POP NOISE PREVENTION CIRCUIT 7 5 33μF 25V + C3 0.47μF 25V C4 C7** +OUT1 OUTPUT PIN TO GND SHORT PROTECTOR +5V PREDRIVER R3 ** (POLYESTER FILM CAPACITOR) VCC 4 RL 4Ω R2 OUTPUT PIN TO GND SHORT PROTECTOR OVER VOLTAGE / SURGE PROTECTOR BIAS CIRCUIT 12 C6** 2.2Ω 2.2Ω − 0.1μF + ñ -OUT1 2.2Ω 2.2Ω 1 2.2μF 25V 13 POWER 0.1μF PREDRIVER 0.1μF RIPPLE FILTER C1 + + 2200μF 25V VCC + C10 C3 Sets the amplifier starting time (Approximately 0.6 seconds when 33µF) C10 Impulse noise reduction (Note : The device’s ability to withstand shorting to VCC or shorting to ground when VCC is around 16V may be reduced as the value of this capacitor is increased. We recommend 0.47µF.) No.5715-3/8 LA4725 Pin Voltages VCC = 13.2V, with 5V applied to STBY through a 10kΩ resistor, RL = 4Ω, Rg = 0 Pin No. 1 2 3 4 5 6 7 Pin name IN1 DC PRE-GND STBY ON TIME IN2 POP Pin voltage 1.53V 5.65V 0V 3.25V 2.32V 1.53V 2.14V Pin No. 8 9 10 11 12 13 14 Pin name +OUT2 −OUT2 PWR-GN +OUT1 PWR-GN −OUT1 VCC Pin voltage 5.70V 5.70V 0V 5.70V 0V 5.70V 13.2V External Components C1 and C4: Input capacitors. A value of 2.2μF is recommended. Determine the polarity based on the DC potential of the circuit connected directly to the LA4725 front end. Note that the low band response can be adjusted by varying fL with the capacitors C1 and C4. C2 : Decoupling capacitor (ripple filter) C3 : Sets the amplifier starting time, which will be approximately 0.6 seconds for a value of 33μF. The starting time is proportional to the value of this capacitor, and can be set to any desired value. C5 : Power-supply capacitor C6, C7, C8, and C9 : Oscillation prevention capacitors. Use polyester film capacitors (Mylar capacitors) with excellent characteristics. (Note that the series resistors R2, R3, R4, and R5 are used in conjunction with these capacitors to achieve stable amplifier operation.) A value of 0.1μF is recommended. C10 : Impulse noise reduction capacitor. A value of 0.47μF is recommended. Caution is required when selecting the value for this capacitor, since increasing its value influences the operation of the circuits that protect against shorting the amplifier output pins to VCC or to ground when higher VCC voltages (approximately 16V or higher) are used. R1 : Standby switch current limiting resistor. A value of 10kΩ is recommended when a voltage in the range 2.5 to 12V will be applied as the standby switching voltage. Note that this resistor is not optional: it must be included. IC Internal Characteristics and Notes 1. Standby function • Pin 4 is the standby switch. A voltage of 2.5V or higher must be applied through an external resistor to turn the amplifier on. • If a voltage of over 12V will be applied as the standby mode switching voltage, use the following formula to determine the value of R1 so that the current entering at pin 4 remains under 500μA. R1 = Pin 4 Internal Equivalent Circuit 500μA or lower 10kΩ 4 R1 Applied standby voltage About 1.4V (2VBE) <applied voltage> − 1.4 − 10kΩ 500μA 2. Muting function • Pin 5 connects the capacitor that determines the starting time to prevent impulse noise. It can also be used to mute the amplifier output by shorting pin 5 to ground. When this function is used, the recovery time depends on C3. 3. Impulse noise improvements • While the LA4725 achieves a low level of impulse noise, if even further reductions in impulse noise at power on/off (and when switching into or out of standby mode) a 0.47μF capacitor may be inserted between pin 7 and the PRE GND pin (pin 3). (Pin 7 is the output amplifier bias pin. Since the ability to withstand shorting the output pins to VCC or ground is reduced for supply voltages over 16V if the pin 7 capacitance is large, we recommend a value of 0.47μF or lower for this capacitor.) No.6631-4/8 LA4725 4. Protection circuits • Due to the system structure of the protection circuit for shorts to VCC or ground, if there is a DC resistance between the amplifier output pins and ground, the protection circuit may operate when power is first applied and the amplifier may fail to turn on. The basic design approach we recommend is not to adopt any designs in which there is a DC resistance between the amplifier outputs and ground. • The LA4725 includes a built-in thermal protection circuit to prevent the IC from being damaged or destroyed if abnormally high temperatures occur. This thermal protection circuit gradually reduces the output if the IC junction temperature (Tj) reaches the range 170 to 180°C due to inadequate heat sinking or other problem. If the temperature falls, the amplifier will restart automatically. • The LA4725 also includes other protection circuits. Use of these circuits also requires care during end product design and testing. 5. Other notes • The LA4725 is a BTL power amplifier. When testing this device, the ground systems for the test equipment connected to IC inputs, and that for the test equipment connected to IC outputs, must be isolated. Do not use a common ground. Printed Circuit Pattern (copper foil side) GND VCC C5 + 14 1 LA4625/LA4725 C1 IN1 + R2 C6 -OUT1 GND + C2 STB R1 R3 C7 +OUT1 + + C3 IN2 C4 + C10 GND R4 C8 R5 C9 -OUT2 +OUT2 No.6631-5/8 LA4725 PO -- VCC 40 f = 1kHz Rg = 600Ω RL = 4Ω 30 Output power, PO -- W Output power, PO -- W 35 % 25 = HD 30 T 20 0% D =1 TH 15 10 5 0 6 7 8 9 10 11 12 13 PO -- VIN 100 7 5 3 2 14 15 16 17 VCC = 13.2V RL = 4Ω f = 1kHz 10 7 5 3 2 1.0 7 5 3 2 0.1 7 5 3 2 0.01 1.0 18 2 3 5 Output power, PO -- W 20 PO -- f THD = 3% 12 THD = 1% 8 2 3 5 7 100 2 3 5 7 1k 2 3 5 7 10k 2 3 2 THD -- PO 1.0 7 5 3 2 f = 1kHz 0.1 7 5 10kHz 100Hz 3 2 2 3 2 3 5 7 100 5 7 1.0 2 3 5 7 10 2 3 5 7 100 CHsep -- f CH1→2 -50 CH2→1 -60 -70 3 2 2 3 5 7 1k 2 3 Frequency, f -- Hz 5 7 10k 2 3 5 7100k 1.0 7 5 3 2 0.1 7 5 3 2 2 3 5 7 100 2 3 5 7 1k 2 3 5 7 10k 2 3 5 7100k VNO --VCC 5 7 10k 2 3 5 7100k Rg = 0 RL = 4Ω 110 100 90 80 70 60 5 7100 2 3 VCC = 13.2V RL = 4Ω PO = 1W Nonfilter 120 -40 2 3 5 7 1k Frequency, f -- Hz VCC = 13.2V RL = 4Ω Rg = 10kΩ VO = 0dBm Nonfilter -80 10 2 3 THD -- f 10 7 5 0.01 10 Output noise voltage, VNO -- mVrms Channel separation, CHsep -- dB -30 7 1k VCC = 13.2V RL = 4Ω Rg = 600Ω VO = 0dBm (f = 1kHz) Output power, PO -- W -20 5 Frequency, f -- Hz VCC = 13.2V RL = 4Ω Rg = 600Ω DIN AUDIO 0.01 0.1 3 -6 -10 10 5 7100k Total harmonic distortion, THD -- % Total harmonic distortion, THD -- % 3 2 -4 Frequency, f -- Hz 10 7 5 7 100 -2 -8 4 0 10 5 0 THD = 10% 16 3 f Response 2 VCC = 13.2V RL = 4Ω Rg = 600Ω Response -- dB 24 2 7 10 Input voltage, VIN -- mVrms Supply voltage, VCC -- V 8 10 12 14 16 18 Supply voltage, VCC -- V No.6631-6/8 LA4725 SVRR -- VCC -30 -40 OUT1 -50 -60 SVRR -- VCCR 0 RL = 4Ω Rg = 0 fR = 100Hz VCCR = 0dBm DIN AUDIO Ripple rejection ratio, SVRR -- dB Ripple rejection ratio, SVRR -- dB -20 OUT2 -70 VCC = 13.2V RL = 4Ω Rg = 0 Nonfilter -20 -40 100Hz OUT1 T2 z OU UT1 3kHz O -60 100H T2 3kHz OU -80 SVRR = 20log -80 8 6 10 12 14 16 -100 18 0 0.2 0.4 SVRR -- fR Quiescent current, ICCO -- mA Ripple rejection ratio, SVRR -- dB OU T1 OUT 2 -80 -100 10 2 3 5 7 100 2 3 5 7 1k 2 3 5 7 10k 2 3 2.0 100 80 60 25 Power dissipation, Pd -- W 10 8 VN -- V 1.8 6 8 10 12 6 4 2 10 15 20 14 16 18 20 22 36 36 36 3 5 36 Supply voltage, VCC -- V RL = 4Ω Rg = 0 25 30 Pd -- PO RL = 4Ω Rg = 600Ω f = 1kHz 20 V .4 15 = C VC 10 V 14 V 3.2 =1 CC 5 0 0.1 2 3 5 7 1.0 2 3 5 7 10 2 7 100 Output power, PO -- W Supply voltage, VCC -- V Amp ON time 0.6 1.6 120 40 5 7100k VN -- VCC 12 5 1.4 140 Ripple frequency, fR -- Hz 0 1.2 RL = 4Ω Rg = 0 -40 -60 1.0 ICCO -- VCC 160 VCC = 13.2V RL = 4Ω Rg = 0 VCCR = 0dBm Nonfilter -20 0.8 Power supply ripple, VCCR -- Vrms Supply voltage, VCC -- V 0 0.6 VO VCCR VCC = 13.2V VST = 5V Amp ON time -- s 0.5 0.4 0.3 0.2 0.1 0 1.0 2 3 5 7 10 2 3 5 7 100 C3 -- μF No.6631-7/8 LA4725 ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). 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