TDA7375A 2 x 37W DUAL/QUAD POWER AMPLIFIER FOR CAR RADIO HIGH OUTPUT POWER CAPABILITY 2 x 43W/4Ω MAX 2 x 37W/4Ω EIAJ 2 x 26W/4Ω @14.4V, 1KHz, 10% 4 x 7W/4Ω @14.4V, 1KHz, 10% 4 x 12W/2Ω @14.4V, 1KHz, 10% MINIMUM EXTERNAL COMPONENTS COUNT: – NO BOOTSTRAP CAPACITORS – NO BOUCHEROT CELLS – INTERNALLY FIXED GAIN (26dB BTL) ST-BY FUNCTION (CMOS COMPATIBLE) NO AUDIBLE POP DURING ST-BY OPERATIONS DIAGNOSTIC FACILITIES – CLIP DETECTOR – OUT TO GND SHORT – OUT TO VS SHORT – SOFT SHORT AT TURN-ON – THERMAL SHUTDOWN PROXIMITY Protections: OUPUT AC/DC SHORT CIRCUIT – TO GND Multiwatt15 V ORDERING NUMBERS: TDA7375AV TDA7375AH – TO VS – ACROSS THE LOAD SOFT SHORT AT TURN-ON OVERRATING CHIP TEMPERATURE WITH SOFT THERMAL LIMITER LOAD DUMP VOLTAGE SURGE VERY INDUCTIVE LOADS FORTUITOUS OPEN GND REVERSED BATTERY ESD BLOCK DIAGRAM October 1998 1/14 TDA7375A DESCRIPTION The TDA7375A is a new technology class AB car radio amplifier able to work either in DUAL BRIDGE or QUAD SINGLE ENDED configuration. The exclusive fully complementary structure of the output stage and the internally fixed gain guaran- tee the highest power performances with extremely reduced component count. The on board clip detector simplifies gain compression operation. The fault diagnostic makes it possible to detect mistakes during car radio set assembly and wiring in the car. GENERAL STRUCTURE ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit Vop Operating Supply Voltage 18 V VS DC Supply Voltage 28 V Peak Supply Voltage (for t = 50ms) 40 V IO Output Peak Current (not repitive t = 100µs) 4.5 A IO Output Peak Current (repetitive f > 10Hz) 3.5 A Power Dissipation Tcase = 85°C 36 W -40 to 150 °C Vpeak Ptot Tstg, Tj Storage and Junction Temperature THERMAL DATA Symbol Rth j-case Description Thermal Resistance Junction-case PIN CONNECTION (Top view) 2/14 Max Value Unit 1.8 °C/W TDA7375A ELECTRICAL CHARACTERISTICS (Refer to the test circuit, VS = 14.4V; RL = 4Ω; f = 1KHz; T amb = 25°C, unless otherwise specified Symbol Parameter VS Supply Voltage Range Id Total Quiescent Drain Current VOS Output Offset Voltage PO Output Power PO max PO EIAJ THD CT Test Condition Min. Typ. 8 RL = ∞ Max. Unit 18 V 150 mA 150 mV THD = 10%; RL = 4Ω Bridge Single Ended Single Ended, RL = 2Ω 23 6.5 26 7 12 W W W VS = 14.4V, Bridge 37 43 W EIAJ Output Power (***) VS = 13.7V, Bridge 33 37 W Distortion R L = 4Ω Single Ended, PO = 0.1 to 4W Bridge, PO = 0.1 to 10W Max. Output Power (***) Cross Talk 0.02 0.03 f = 1KHz Single Ended f = 10KHz Single Ended f = 1KHz Bridge f = 10KHz Bridge 55 dB dB 60 dB dB KΩ KΩ Input Impedance Single Ended Bridge 20 10 30 15 GV Voltage Gain Single Ended Bridge 19 25 20 26 GV Voltage Gain Match EIN Input Noise Voltage Bridge Rg = 0; 22Hz to 22KHz SVR Supply Voltage Rejection R g = 0; f = 300Hz 50 A SB Stand-by Attenuation PO = 1W 80 ISB ST-BY Current Consumption VST-BY = 0 to 1.5V V SB ST-BY In Threshold Voltage V SB ST-BY Out Threshold Voltage Ipin7 ST-BY Pin Current % % 70 60 R IN R g = 0; ”A” weighted, S.E. Non Inverting Channels Inverting Channels 0.3 21 27 dB dB 0.5 dB 2 5 µV µV 3.5 µV 90 dB dB 1.5 µA V Play Mode V pin7 = 5V 50 µA Max Driving Current Under Fault (*) 5 mA 100 3.5 V Icd off Clipping Detector Output Average Current d = 1% (**) 90 µA Icd on Clipping Detector Output Average Current d = 5% (**) 160 µA Voltage Saturation on pin 10 Sink Current at Pin 10 = 1mA Vsat pin10 0.7 V (*) See built-in S/C protection description (**) Pin 10 Pulled-up to 5V with 10KΩ; RL = 4Ω (***) Saturated square wave output. 3/14 TDA7375A STANDARD TEST AND APPLICATION CIRCUIT Figure 1: Quad Stereo 10K R1 VS C5 1000µF ST-BY C7 10µF 7 4 IN FL C6 100nF 13 3 1 C1 0.22µF IN FR 5 12 C4 0.22µF Note: The output decoupling capacitors (C9,C10,C11,C12) could be reducedto 1000µF if t he 2Ω operation is not required. OUT FL C9 2200µF OUT FR C11 2200µF OUT RL C12 2200µF OUT RR 2 C2 0.22µF IN RL C10 2200µF 15 IN RR 11 C3 0.22µF 6 14 8 9 10 C8 47µF DIAGNOSTICS D94AU063A Figure 2: Double Bridge 10K R1 VS C3 1000µF ST-BY C4 100nF C5 10µF IN L C1 0.47µF IN R 13 7 4 3 1 OUT L 5 2 12 C2 0.47µF 15 11 OUT R 14 6 C8 47µF 8 9 10 DIAGNOSTICS D94AU064A Figure 3: Stereo/Bridge 10K VS ST-BY 10µF 13 7 4 IN L 100nF 3 1 0.22µF 2 2200µF 0.22µF IN BRIDGE OUT BRIDGE 11 6 8 OUT R 15 12 0.47µF OUT L 2200µF 5 IN L 1000µF 9 10 14 47µF DIAGNOSTICS 4/14 D94AU065A TDA7375A Figure 4: P.C. Board and Component Layout of the fig.1 (1:1 scale). Figure 5: P.C. Board and Component Layout of the fig.2 (1:1 scale). 5/14 TDA7375A Figure 6: Quiescent Drain Current vs. Supply Voltage (Single Ended and Bridge). Figure 7: Quiescent Output Voltage vs. Supply Voltage (Single Ended and Bridge). Figure 8: Output Power vs. Supply Voltage Figure 9: Output Power vs. Supply Voltage Figure 10: Output Power vs. Supply Voltage Figure 11: Distortion vs. Output Power 6/14 TDA7375A Figure 12: Distortion vs. Output Power Figure 13: Distortion vs. Output Power Figure 14: Cross-talk vs. Frequency Figure 15: Supply Voltage Rejection vs. Frequency Figure 16: SupplyVoltage Rejection vs. Frequency Figure 17: Stand-byAttenuation vs. Threshold Voltage 7/14 TDA7375A Figure 18: Total Power Dissipation and Efficiency vs. Output Power 8/14 Figure 19: Total Power Dissipation and Efficiency vs. Output Power. TDA7375A High Application Flexibility The availability of 4 independent channels makes it possible to accomplish several kinds of applications ranging from 4 speakers stereo (F/R) to 2 speakers bridge solutions. In case of working in single ended conditions the polarity of the speakers driven by the inverting amplifier must be reversed respect to those driven by non inverting channels. This is to avoid phase inconveniences causing sound alterations especially during the reproduction of low frequencies. Easy Single Ended to Bridge Transition The change from single ended to bridge configurations is made simply by means of a short circuit across the inputs, that is no need of further external components. Gain Internally Fixed to 20dB in Single Ended, 26dB in Bridge Advantages of this design choice are in terms of: components and space saving output noise, supply voltage rejection and distortion optimization. Silent Turn On/Off and Muting/Stand-by Function The stand-by can be easily activated by means of a CMOS level applied to pin 7 through a RC filter. Under stand-by condition the device is turned off completely (supply current = 1µA typ.; output attenuation= 80dB min.). Every ON/OFF operation is virtually pop free. Furthemore, at turn-on the device stays in muting condition for a time determined by the value assigned to the SVR capacitor. While in muting the device outputs becomes insensitive to any kinds of signal that may be present at the input terminals. In other words every transient coming from previous stages produces no unplesant acoustic effect to the speakers. OUTPUT STAGE The fully complementary output stage was made possible by the development of a new component: the ST exclusive power ICV PNP. A novel design based upon the connection shown in fig. 20 has then allowed the full exploitation of its possibilities. The clear advantages this new approach has over classical output stages are as follows: Rail-to-Rail Output Voltage Swing With No Need of Bootstrap Capacitors. The output swing is limited only by the VCEsat of the output transistors, which are in the range of 0.3Ω (Rsat) each. Classical solutions adopting composite PNPNPN for the upper output stage have higher saturation loss on the top side of the waveform. This unbalanced saturation causes a significant power reduction. The only way to recover power consists of the addition of expensive bootstrap capacitors. Absolute Stability Without Any External Compensation. Referring to the circuit of fig. 20 the gain VOut/VIn is greater than unity, approximately 1+ R2/R1. The DC output (VCC/2) is fixed by an auxiliary amplifier common to all the channels. By controlling the amount of this local feedback it is possible to force the loop gain (A*β) to less than unity at frequency for which the phase shift is 180°. This means that the output buffer is intrinsically stable and not prone to oscillation. Most remarkably, the above feature has been achieved in spite of the very low closed loop gain of the amplifier. In contrast, with the classical PNP-NPN stage, the solution adopted for reducing the gain at high frequencies makes use of external RC networks, namely the Boucherot cells. Figure 20: The New Output Stage BUILT–IN SHORT CIRCUIT PROTECTION Reliable and safe operation, in presence of all kinds of short circuit involving the outputs is assured by BUILT-IN protectors. Additionally to the AC/DC short circuit to GND, to VS, across the speaker, a SOFT SHORT condition is signalled out during the TURN-ON PHASE so assuring cor9/14 TDA7375A rect operation for the device itself and for the loudspeaker. This particular kind of protection acts in such a way to avoid the device is turned on (by ST-BY) when a resistive path (less than 16 ohms) is present between the output and GND. As the involved circuitry is normally disabled when a current higher than 5mA is flowing into the ST-BY pin, it is important, in order not to disable it, to have the external current source driving the STBY pin limited to 5mA. This extrafunction becomes particularly attractive when, in the single ended configuration, one capacitor is shared between two outputs (see fig. 21). Figure 22: Clipping Detection Waveforms Figure 21. A current sinking at pin 10 is provided when a certain distortion level is reached at each output. This function allows gain compression facility whenever the amplifier is overdriven. Supposing that the output capacitor C out for any reason is shorted, the loudspeaker will not be damaged being this soft short circuit condition revealed. Diagnostic Facilities The TDA7375 is equipped with a diagnostic circuitry able to detect the following events: Clipping in the output signal Thermal shutdown Output fault: – short to GND – short to VS – soft short at turn on The information is available across an open collector output (pin 10) through a current sinking when the event is detected 10/14 Thermal Shutdown In this case the output 10 will signal the proximity of the junction temperature to the shutdown threshold. Typically current sinking at pin 10 will start ~10°C before the shutdown threshold is reached. HANDLING OF THE DIAGNOSTIC INFORMAFigure 23: Output Fault Waveforms (see fig. 24) TDA7375A TDA7375A Figure 24: Fault Waveforms ST-BY PIN VOLTAGE 2V t OUT TO Vs SHORT OUTPUT WAVEFORM SOFT SHORT t OUT TO GND SHORT Vpin 10 CORRECT TURN-ON FAULT DETECTION t CHECK AT TURN-ON (TEST PHASE) TION As different kinds of information is available at the same pin (clipping detection, output fault, thermal proximity), this signal must be handled properly in order to discriminate the event. Figure 25: Waveforms D94AU149A SHORT TO GND OR TO Vs This could be done taking into account the different timing of the diagnostic output against different events. Normally the clip detector signalling produces a low level at out 10 that is shorter referred to every ST-BY PIN VOLTAGE t Vs OUTPUT WAVEFORM t Vpin 10 WAVEFORM t CLIPPING D94AU150 SHORT TO GND OR TO Vs THERMAL PROXIMITY 11/14 TDA7375A kind of fault detection; based on this assumption an interface circuitry to differentiate the information is represented in the following schematic. Figure 26. TDA7375A 12/14 TDA7375A mm DIM. MIN. inch A MAX. 5 B C 2.65 1.6 D TYP. MIN. 0.49 0.66 G G1 1.02 17.53 H1 19.6 OUTLINE AND MECHANICAL DATA 0.039 0.55 0.75 0.019 0.026 1.27 17.78 1.52 18.03 0.040 0.690 21.9 22.2 20.2 22.5 L1 21.7 22.1 L2 L3 17.65 17.25 17.5 L4 L7 10.3 2.65 H2 L MAX. 0.197 0.104 0.063 1 E F TYP. 0.022 0.030 0.050 0.700 0.060 0.710 0.862 0.874 0.795 0.886 22.5 0.854 0.870 0.886 18.1 17.75 0.695 0.679 0.689 0.713 0.699 10.9 2.9 0.406 0.104 0.772 10.7 0.421 0.429 0.114 M 4.25 4.55 4.85 0.167 0.179 0.191 M1 S S1 4.63 1.9 1.9 5.08 5.53 2.6 2.6 0.182 0.075 0.075 0.200 0.218 0.102 0.102 Dia1 3.65 3.85 0.144 Multiwatt15 V 0.152 13/14 TDA7375A Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics 1998 STMicroelectronics – Printed in Italy – All Rights Reserved MULTIWATT is a Registered Trademark of the STMicroelectronics STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com 14/14