Ordering number: EN5245A Monolithic Linear IC LA4708 20 W 2-channel BTL AF Power Amplifier for Car Stereos Overview Package Dimensions The LA4708 is a BTL two-channel power IC for car audio developed in pursuit of excellent sound quality. Low-region frequency characteristics have been improved through the use of a new NF capacitorless circuit, and crosstalk which causes ‘‘muddy’’ sound has been reduced by improving both circuit and pattern layout. As a result, the LA4708 provides powerful bass and clear treble. In addition, the LA4708 features on-chip protectors and standby switch. The LA4708 is also pin-compatible with the LA4705NA (car stereo-use 17 W two-channel power IC), and can be substituted for the LA4705NA for higher power. (When the board is shared, pins 1 and 9 must be left open.) unit: mm 3109-SIP18H [LA4708] Features . High power: supports total output of 30 W + 30 W = 13.2 V, THD = 30%, R = 4 Ω) . (VSupports R = 2 Ω (P = 30 W when V = 13.2 V, THD = 10%) . Designed for excellent sound quality 10 Hz, f = 130 kHz) . (fNF <capacitorless . Any on time settable by external capacitor . Less pop noise . Standby switch circuit on chip (microprocessor supported) . Various protectors on chip CC L L SANYO : SIP18H L O CC H (output-to-ground short/output-to-VCC short/ load short/overvoltage/thermal shutdown circuit) Specifications Maximum Ratings at Ta = 25°C Parameter Maximum supply voltage Symbol VCC max 1 Conditions No signal, t = 60 s VCC max 2 Surge supply voltage VCC surge Ratings Unit 24 V 16 V t % 0.2 s, single giant pulse 50 V 4.5 A Maximum output current IO peak Per channel Allowable power dissipation Pd max Arbitrarily large heat sink 37.5 W Operating temperature Topr –35 to +85 °C Storage temperature Tstg –40 to +150 °C * Set VCC, RL in a range that does not exceed Pd max = 37.5 W SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN 93096HA(II)/13096HA(II) No.5245-1/9 LA4708 Operating Conditions at Ta = 25°C Parameter Recommended supply voltage Operating voltage range Symbol Conditions Ratings VCC VCC op Recommended load resistance RL Recommended load resistance range RL op Range where Pd max is not exceeded Unit 13.2 V 9 to 16 V 4 Ω 2 to 4 Ω Operating Characteristics at Ta = 25°C, VCC = 13.2 V, RL = 4 Ω, f = 1 kHz, Rg = 600 Ω Output power Allowable power dissipation, Pd max — W Output offset voltage Output noise voltage Ripple rejection ratio Channel separation Input resistance Standby pin applied voltage Symbol ICCO Ist VG THD PO1 PO2 PO3 VN offset VNO SVRR CHsep ri Vst Conditions min 70 38 PO = 2 W THD = 10% THD = 10%, VCC = 14.4 V THD = 10%, RL = 2 Ω Rg = 0 Rg = 0, B.P.F. = 20 Hz to 20 kHz Rg = 0, fR = 100 Hz, VR = 0 dBm Rg = 10 kΩ, VO = 0 dBm Amp on, applied through 10 kΩ Arbitrarily large heat sink Ambient temperature, Ta — °C Heat sink thermal resistance, θf — °C/W Parameter Quiescent current Standby current Voltage gain Total harmonic distortion 16 typ 150 10 40 0.07 20 24 30 –300 40 50 21 2.5 0.1 50 60 30 max 250 60 42 0.4 +300 0.5 39 VCC Unit mA µA dB % W W W mV mVrms dB dB kΩ V Al heat sink, t = 1.5 mm Tightening torque 39 Nccm With silicone grease applied Heat sink area, Sf — cm2 No.5245 -2/9 LA4708 Equivalent Circuit Block Diagram - - - - Pins 1,9 : Don’t use Pin 10 : No connection Each Pin Voltage VCC = 13.2 V, 5 V applied through STBY = 10 kΩ, RL = 4 Ω, Rg = 0 Pin No. 1 Name Pin voltage (V) 0.29 2 3 4 5 6 IN1 DC Pre-GND STBY ON TIME 1.58 6.55 0 3.2 2.28 Pin No. 7 8 9 10 11 12 Name IN2 POP – N.C VCC2 –OUT 2 Pin voltage (V) 1.58 2.08 0.29 0 13.2 6.5 Pin No. 13 14 15 16 17 18 Name PWR–GND 2 +OUT 2 +OUT 1 PWR–GND 1 –OUT 1 VCC1 Pin voltage (V) 0 6.5 6.5 0 6.5 13.2 No.5245 -3/9 LA4708 Sample Print Pattern Copper foil area 90 × 105 mm2 Description of External Components C1, C4 Input capacitors 2.2 µF is recommended. fL can be varied by C1, C4 capacitances to adjust the bass range. C2 Decoupling capacitor (ripple filter) C3 Amplifier on time setting capacitor C5 Power supply capacitor C6, C7, C8, C9 Oscillation blocking capacitors Use polyester film capacitors (Mylar capacitors) with good temperature characteristics. (R2, R3, R4, and R5 used jointly.) Since stability may be affected slightly by the pattern layout, etc., 0.1 µF or more is recommended. R1 Standby switch current limiting resistor 10 kΩ is recommended (when the applied voltage for the standby switch is 2.5 V to 13.2 V). This resistor cannot be removed. Approximately 0.8 second for 33 µF. Since the on time is proportional to this capacitance, it can be set as desired by varying this capacitance. (Refer to the characteristics curve.) No.5245 -4/9 LA4708 Features of IC Inside and Usage Notes Standby function . Pin 5 is the standby switch pin. The amplifier is turned on by applying approximately 2.5 V or more to this pin through an resistor (R1). . external If voltage in excess of 13.2 V is to be applied to the standby switch, calculate the value of R1 using the following formula so that the current flowing into pin 5 is 500 µA or less: R1 = Applied voltage − 1.4 V 500 µA – 10 kΩ 500 µA or less Pin 5 Equivalent circuit internal IC Standby About 1.4 V applied voltage (2V ) BE Mute function . Pin 6 is the connector for the capacitor that determines the on time in order to prevent pop noise. By grounding this pin, the amplifier can implement mute operation. In this case, the recovery time depends on C3. How to reduce pop noise . Although the LA4708 reduces pop noise, an electrolytic capacitor of between 0.47 and 2.2 µF can be connected between pin 8 and the pre-GND to further reduce pop noise that occurs when power supply is turned on/off (standby switch on/off). The larger the capacitance, the lower the frequency of pop noise, and it is barely audible, but sound residue of the sound signal is liable to linger when power is turned off. Pin 8 is the bias pin for the output amplifier and normally is left open. Protectors . In an output-to-ground and output-to-V CC short protector system configuration, if a DC resistor is connected between amplifier output pin and GND, the protector may operate, causing the amplifier not to start operating. Therefore, as a general rule, no DC resistor should be connected between amplifier output pin and GND. In order to prevent damage or degradation which may be caused by abnormally heated IC, the LA4708 has a thermal shutdown protector. Accordingly, if the IC junction temperature (Tj) climbs to around 170 to 180°C due to inadequate heat dissipation, the thermal shutdown protector will operate to control the output gradually into attenuation. Also be fully careful of handling other protectors built in the LA4708. . . Miscellaneous . Since pins 1 and 9, which are unused, are connected internally, they must be left open. . Pin 10 is an NC pin (no internal connection). No.5245 -5/9 Output power, PO — W Quiescent current, ICCO — mA LA4708 Input level, VIN — mVrms Exceeding Pd max Output power, PO — W Output power, PO — W Supply voltage, VCC — V Dual channel drive Output power, PO — W Total harmonic distortion, THD — % Dual channel drive Supply voltage, VCC — V Total harmonic distortion, THD — % Total harmonic distortion, THD — % Supply voltage, VCC — V Dual channel drive Dual channel drive Dual channel drive Output power, PO — W Response — dB VO = 0 dBm at f = 1 kHz Input frequency, f — Hz Input frequency, f — Hz No.5245 -6/9 Output power, PO — W Channel separation, CHsep — dB LA4708 Dual channel drive Input frequency, f — Hz Ripple rejection ratio, SVRR — dB Output noise voltage, VNO — mVrms Input frequency, f — Hz Supply voltage, VCC — V Ripple rejection ratio, SVRR — dB The value of power supply capacitor is 0.47 µF (Mylar) Output power, PO — W Power dissipation, Pd — W Dual channel drive Power supply ripple voltage, VCCR — Vrms Current drain, ICC — A Power dissipation, Pd — W Ripple frequency, fR — Hz The value of power supply capacitor is 0.47 µF(Mylar) Calculate as Dual channel drive Allowable power dissipation of package Current drain, ICC — A Ripple rejection ratio, SVRR — dB Input resistance, Rg — Ω 2200 µF (power supply capacitor) is changed to 0.47 µF (Mylar) Output power, PO — W No.5245 -7/9 Output pin voltage, VN — V Quiescent current, ICCO — mA LA4708 Dual channel drive Ambient temperature, Ta — °C Total harmonic distortion, THD — % Output power, PO — W Supply voltage, VCC — V Ambient temperature, Ta — °C Amp ON time — s Output pin voltage, VN — V Ambient temperature, Ta — °C Dual channel drive Apply VST to standby pin (pin 5) through 10 kΩ. Standby pin applied voltage, VST — V (Apply to pin 5 through 10 kΩ.) C3 — µF No.5245 -8/9 LA4708 No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. Anyone purchasing any products described or contained herein for an above-mentioned use shall: 1 Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: 2 Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provides information as of September, 1996. Specifications and information herein are subject to change without notice. No.5245 -9/9