Ordering number : EN6632A LA4628 Monolithic Linear IC 20W 2-Channel BTL Power Amplifier for General Audio http://onsemi.com Overview The LA4628 is a 2-channel general-purpose BTL audio power amplifier provided in a miniature package. 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. Note that this device is pin compatible with the 13.5W×2-channel LA4625, and allows end products differentiated by their power rating to share the same printed circuit board. Features • Total output : 20W+20W (at VCC = 13.5V, RL = 4Ω, THD = 10%) • High-fidelity design (fL < 10Hz, fH = 130kHz) • Extremely low impulse noise levels • An arbitrary amplifier startup time can be set up with external components. • Full complement of built-in protection circuits (includes circuits that protect against shorting to VCC, shorting to ground, load shorting, overvoltages and excessive temperatures) Specifications Maximum Ratings at Ta = 25°C Parameter Symbol Conditions Maximum supply voltage VCC max No signal Maximum output current IO peak Per channel Allowable power dissipation Pd max With an arbitrarily large heat sink Operating temperature Storage temperature Ratings Unit 24 V 4 A 32.5 W Topr -20 to +85 °C Tstg -40 to +150 °C 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 O0808 MS JK/92900RM(OT) No.6632-1/8 LA4628 Operating Conditions at Ta = 25°C Symbol Parameter Conditions Ratings Unit Recommended supply voltage VCC 13.5 V Recommended load resistance range RL op 4 to 8 Ω Allowable operating supply voltage range VCC op 9 to 20 V 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 = 13.5V, RL = 4Ω, f = 1kHz, Rg = 600Ω Ratings Parameter Symbol Conditions min Quiescent current ICCO With Rg = 0 and RL open. Standby mode current drain Ist Standby mode (amplifier off), with no power typ 70 Unit max 130 250 mA 10 60 μA 40 42 dB 0.06 0.2 supply capacitor. Voltage gain VG VO = 0dBm Total harmonic distortion THD PO = 1W, Filter = FLAT 38 Output power PO1 VCC = 13.5V, THD = 10%, RL = 4Ω 16 % 20 PO2 VCC = 16.5V, THD = 10%, RL = 4Ω Output offset voltage VN offset Rg = 0 Output noise voltage VNO Rg = 0, BPF = 20Hz to 20kHz Ripple rejection ratio SVRR Rg = 0, VR = 0dBm, fR = 100Hz 40 50 Channel separation CHsep Rg = 10kΩ, VO = 0dBm 50 60 Input resistance Ri 21 30 Standby pin applied voltage VST W 30 W -300 0.1 Amplifier on +300 mV 0.5 mV dB dB 39 2.5 KΩ VCC V (applied through an external 10kΩ resistor) Package Dimensions unit : mm (typ) 3113B Allowable power dissipation, Pd max -- W 35 32.5 Pd max -- Ta AI heat sink Mounting torque 39N cm Flat washer Silicone grease applied Infinite heat sink 30 25 20.83 20 θf = 3˚C/W θf = 4˚C/W θjc = 2˚C/W 15 13.9 10.4 10 5 3.1 θf = 7˚C/W θf = 10˚C/W Νο Fin 0 -20 0 20 40 60 80 100 120 140 160 Ambient temperature, Ta -- ˚C No.6632-2/8 LA4628 Block Diagram C2 100μF/16V + C5 14 2 OUTPUT PIN TO VCC SHORT PROTECTOR PREDRIVER PRE GND 3 R1 ON 10KΩ OFF STANDBY SW THERMAL SHUT DOWN PREDRIVER 6 + 2.2μF 10V – 9 POWER LOAD SHORT PROTECTOR IN PREDRIVER C7** 0.1μF +OUT1 + OUTPUT PIN TO GND SHORT PROTECTOR IN2 POWER GND2 10 8 POWER – -OUT2 C8** RL 4Ω R4 R5 C9** +OUT2 + OUTPUT PIN TO VCC SHORT PROTECTOR POP NOISE PREVENTION CIRCUIT 5 + 7 C3 0.47μF 10V + R3 ** (POLYESTER FILM CAPACITOR) VCC 4 RL 4Ω R2 OUTPUT PIN TO GND SHORT PROTECTOR +5V C4 12 11 POWER OVER VOLTAGE / SURGE PROTECTOR BIAS CIRCUIT 33μF 10V Standby SW POWER GND1 LOAD SHORT PROTECTOR IN C6** 2.2Ω 2.2Ω – 0.1μF + – -OUT1 2.2Ω 2.2Ω 1 2.2μF 10V 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.6632-3/8 LA4628 Pin Voltages VCC = 13.5V, 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 1.55V 6.63V 0V 3.21V 2.32V 1.55V 2.07V Pin No. 8 9 10 11 12 13 14 Pin name +OUT2 -OUT2 PWR–GND +OUT1 PWR–GND -OUT1 VCC Pin voltage 6.6V 6.5V 0V 6.5V 0V 6.6V 13.5V 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 LA4628 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 13.5V 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 13.5V 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 = <applied voltage>−1.4 500μA Pin 4 Internal Equivalent Circuit 500μA or lower 10kΩ 4 R1 Applied standby voltage About 1.4V (2VBE) −10kΩ 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. No.6632-4/8 LA4628 3. Impulse noise improvements • While the LA4628 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.) 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 LA4628 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 LA4628 also includes other protection circuits. Use of these circuits also requires care during end product design and testing. 5. Other notes • The LA4628 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 C5 VCC 14 1 + LA4628 C1 IN1 + + C2 -OUT1 R2 C6 STB GND R1 +OUT1 R3 + + C3 IN2 C7 C4 + C10 -OUT2 GND R4 C8 R5 C9 +OUT2 No.6632-5/8 LA4628 PO -- VCC 40 35 30 Output power, PO -- W Output power, PO -- W 100 7 5 3 2 f = 1kHz Rg = 600Ω THD = 10% Ω 25 =4 RL 20 RL =6 Ω 15 10 5 0 6 7 8 9 10 11 12 13 14 15 16 17 PO -- f THD = 10% Response -- dB 10 5 3 2 2 3 5 7 1k 2 3 Frequency, f -- Hz 5 7 10k 2 3 THD -- PO 1.0 7 5 10kHz 3 2 0.1 7 5 100Hz 1kHz 3 2 2 3 5 7 1.0 2 3 5 7 10 2 3 Output power, PO -- W VCC = 13.5V RL = 4Ω RO = 1W 3 2 1.0 7 5 3 2 0.1 7 5 3 2 0.01 10 3 5 7 10 2 3 5 7 100 2 3 Input voltage, VIN -- mVrms 5 7 1k f Response -4 -6 10 7 5 3 2 VCC = 13.5V RL = 4Ω Rg = 600Ω VO = 0dBm at 1kHz 2 3 5 7 100 2 3 5 7 1k 2 3 Frequency, Ta -- °C 5 7 10k 2 3 5 7100k THD -- PO VCC = 13.5V RL = 6Ω Rg = 600Ω 1.0 7 5 3 2 10kHz 0.1 7 5 1kHz 3 2 0.01 0.1 5 7 100 THD -- f 10 7 5 2 -2 -10 10 5 7100k VCC = 13.5V RL = 4Ω Rg = 600Ω 0.01 0.1 Total harmonic distortion, THD -- % 5 7 100 0.1 7 5 3 2 -8 Total harmonic distortion, THD -- % Total harmonic distortion, THD -- % 10 7 5 VCC = 13.5V RL = 4Ω Rg = 600Ω 100Hz 2 3 5 7 1.0 2 3 5 7 10 2 3 Output power, PO -- W 5 7 100 CHsep -- f 0 VCC = 13.5V RL = 4Ω Rg = 10kΩ VO = 0dBm -10 Channel separation, CHsep -- dB Output power, PO -- W THD = 1% 2 3 1.0 7 5 3 2 0 THD = 3% 0 10 10 7 5 3 2 2 20 15 VCC = 13.5V RL = 4Ω f = 1kHz 0.01 1.0 18 Supply voltage, VCC -- V 25 PO -- VIN -20 -30 -40 -50 CH12 -60 CH21 -70 -80 2 3 5 7 100 2 3 5 7 1k 2 3 Frequency, f -- Hz 5 7 10k 2 3 5 7100k -90 10 2 3 5 7 100 2 3 5 7 1k 2 3 Frequency, f -- Hz 5 7 10k 2 3 5 7100k No.6632-6/8 LA4628 Output noise voltage, VNO -- mVrms 7 5 VNO -- Rg 3 2 0.1 7 5 3 2 0.01 100 2 3 5 7 1k 2 3 5 SVRR -- VCC 0 VCC = 13.5V RL = 4Ω DIN AUDIO Ripple rejection ratio, SVRR -- dB 1.0 7 10k 2 3 5 -20 -40 OUT1 OUT2 -60 -80 -100 -120 7 100k Rg = 0 fR = 100Hz VCCR = 0dBm 5 7 9 Signal source resistance, Rg -- Ω VCC = 13.5V RL = 4Ω Rg = 0Ω -40 100Hz OUT1 100Hz OUT2 -60 3kHz OUT2 3kHz OUT1 -80 Calculated at SVRR = 20log -100 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 VO VCCR 1.8 Pd -- PO (RL = 4Ω) ) 5V (1 Pd 16 3. (1 6.5 V) 20 19 21 23 12 VCC = 13.5V RL = 4Ω Rg = 0 VCCR = 0dBm OUT1 -60 OUT2 -80 2 3 5 7 100 2 3 5 7 1k 2 3 5 7 10k 2 3 Ripple frequency, fR -- Hz 5 7100k Pd -- PO (RL = 6Ω) RL = 6Ω Rg = 600Ω f = 1kHz Calculated at Pd = (VCC × ICC) - (2PO) 28 Power dissipation, Pd -- W 24 17 -40 32 RL = 4Ω Rg = 600Ω f = 1kHz Calculated at Pd = (VCC × ICC) - (2PO) Pd Power dissipation, Pd -- W 28 15 -20 -100 10 2.0 Power supply ripple, VCCR -- Vrms 32 13 SVRR -- fR 0 Ripple rejection ratio, SVRR -- dB Ripple rejection ratio, SVRR -- dB SVRR -- VCCR -20 11 Supply voltage, VCC -- V 24 20 V) 6.5 18 1 d( P 12 Pd ) .5V (13 8 4 0 0.1 2 3 5 7 1.0 2 3 5 7 10 2 3 5 7 100 Output power, PO -- W/CH 6 2 3 5 7 1.0 2 3 5 7 10 2 3 5 7 100 Output power, PO -- W/CH ICC -- PO RL = 4/6Ω Rg = 600Ω f = 1kHz R L= 4Ω 4 3 R L= 6Ω Current drain, ICC -- A 5 0 0.1 2 1 0 0.1 2 3 5 7 1.0 2 3 5 7 10 Output power, PO -- W/CH 2 3 5 7 100 No.6632-7/8 LA4628 ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). 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