TDA7335 STEREO PREAMP + AMS + DOLBY B* NOISE REDUCTION PROCESSOR DUAL CHANNEL PROCESSOR FOR PLAYBACK APPLICATIONS. STEREO DOLBY B NR SYSTEM LOW NOISE HEAD PREAMPLIFIER MUTE, AUTOREVERSE, AMS (AUDIO MUSIC SENSOR) FUNCTIONS INTERNAL SWITCHES FOR EQUALIZATION DOLBY REFERENCE LEVEL -6dBm (388.2mVRMS) MINIMUM NUMBER OF EXTERNAL COMPONENTS LOW SUPPLY CURRENT (18mA) MIXED BIPOLAR/CMOS TECHNOLOGY DESCRIPTION The TDA7335 is a monolithic BICmos IC designed for use in stereo cassette player systems. The device includes two separate audio channels composed by low noise preamplifier, Dolby B noise reduction system and Audio Music Sensor. The dual preamplifier contains mute, autoreverse, metal/normal facilities for amplification of low level signal in applications requiring very low noise performances. Each channel consists of two cascaded operational amplifiers. The first one, AMP1, has a fixed gain of 36dB, low noise forward/reverse switchable input, and allows magnetic heads connection directly to ground. The second one, AMP2, is a standard operational amplifier whose equalizing external components fix the frequency response. The Audio Music Sensor circuit detects the interprogram space and then the starting point of musical programs (the interprogram time and program detection time are externally selectable). The device contains Dolby B decoder NR chains requiring very few external components and do not require coils. SDIP30 ORDERING NUMBER: TDA7335 PIN CONNECTION (Top view) * Dolby B and the Double-D symbol are trademarks of Dolby Laboratories Licensing Corporation, San Francisco, California 94103-4813, USA. This device is available only to Licensing and application information may be obtained from Dolby Lab. November 1999 1/20 TDA7335 ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit VS Supply Voltage 12 V Ptot Total Power Dissipation 1 W Top Operating Temperature Range -40 to 85 °C Tstg Storage Temperature Range -40 to 150 °C 85 °C/W THERMAL DATA Rth j-pins Thermal resistance junction-pins PIN FUNCTIONS N. Name 1 GND VDC (V) Function Ground 2,3 IN L1, IN L2 0 4,27 EQLI, EQRI 4.6 Equalizer Inputs 5, 26 EQLO, EQRO 4.6 Equalizer Outputs 6, 25 OUTL, OUTR 4.6 Preamplifier Outputs 7, 24 DINL, DINR Vref Dolby NR Inputs 8 AMS SW 5.6 Audio Music Sensor Switch (ON/OFF) HIGH = ON 9 INTP Interprogram Time Constant (”Signal Detection”) 10 INTS Interspace Time Constant (”Blank Detection”) 11 MUTE 12, 19 TLC, TCR 13, 18 DOUTL, DOUTR Mute Switch ON = LOW (2) 0.4 Dolby Time Constants Vref Dolby Outputs Reference Current Source 14 Iref 1.2 15 F/R SW 5.6 16 VS 17 Vref 20 NR SW 21 AMS GIN 22 AMS OUT Preamplifier Left Inputs 1,2 Forward/Reverse Switch HIGH = Forward LOW = Reverse Positive Power Supply VS/2 Reference Voltage Noise reduction ON/OFF: HIGH = OFF (2) 1.4 Audio Music Sensor Input Pin Audio Music Sensor Output Pin (open collector configuration, see Fig. 2) 23 GND DIG. 0 Digital Ground 28, 29 IN R1, IN R2 0 Preamplifier Right Inputs 1,2 30 EQ SW 0 Equalizer Switch (Low = normal position High = metal position) (2) Internal pull-up resistor (digital high level if pin left open) 2/20 INPUT L INPUT R 3 INL2 4 AMP1 AMP1 R1 1.2K TR1 1K EQLI 36dB 36dB 27 EQRI R2 TR2 6.8K R3 R4 300K 5 RM AMP2 AMP2 RM 26 R6 300K R5 (*) Capacitor tolerance is ±10% 1µF C1 2 29 INR1 INL1 28 INR2 1µF C2 0.68µF C17 10nF C4 RN 30 0.68µF C20 10nF C3 EQLO 15 RN EQRO 25 R14 6 1.2K 1.2K 30K GND GND Vs 0.33µF C5(*) 7 24 0.33µF C6(*) OUTR R12 OUTL DINR DINL C15 10nF F/R SW EQ SW VS 8 21 R8 10K AMS 23 0.22µF C8 AMSSW AMSGin 30K 470K R7 6.8K 9 INTP Vs 10 22 AMSout INTS C7 0.1µF 1.2K VS 0.68µF (*) 100K R9 C10 OUTL C12 4.7µF 11 MUTE 13 DOUTL BIAS DOUTR 12 DOLBY DOLBY 18 0.68µF (*) TCR 4.7µF C13 OUTR TCL 19 C11 R10 100K C9 1µF 1K R15 30K IREF D94AU095B VS Vs GND R11 43K 2% GND Vs 0.68µF C19 0.22µF C18 R13 100K 4.7µF C14 GND C16 100nF 14 1 VS VREF 17 16 NRSW 20 TDA7335 Figure 1: Application Circuit 3/20 TDA7335 Figure 1a: Components& Top Copper Layer of the Fig. 1 (1:1 scale). Figure 1b: Bottom Copper Layer of the Fig. 1 (1:1 scale). 4/20 300pF INPUT L 300pF INPUT R 600Ω 300pF 600Ω 300pF 4 R3 6.8K 1.8K R4 300K 5 RM AMP2 AMP2 R1 EQLI 36dB AMP1 AMP1 RM 26 R6 (*) Capacitor tolerance is ±10% 3 INL2 600Ω 2 INL1 1µF C1 29 INR1 600Ω 28 INR2 36dB 27 EQRI 300K R5 10nF C4 GND 10nF C3 EQLO RN 30 15 RN EQRO F/R SW 6 1.2K 1.2K 25 0.33µF C5(*) 7 24 0.33µF C6(*) OUTR VS EQ SW R2 OUTL 1µF C2 8 21 R8 10K AMSSW DINR DINL C15 10nF AMSGin AMS 23 10 9 22 18 VS 0.68µF (*) 100K R9 C10 MUTE 11 BIAS DOUTR C12 4.7µF OUTL 13 DOUTL 12 DOLBY DOLBY TCR 4.7µF C13 OUTR 0.68µF (*) TCL 19 C11 R10 100K VS INTP 0.22µF C8 470K R7 AMSout INTS C7 0.1µF 6.8K C9 1µF 1.8K 14 D94AU097A IREF GND 4.7µF C14 VS 16 1 VREF 17 VS R11 43K VS 0.22µF C18 GND NRSW 20 TDA7335 TEST CIRCUIT 5/20 TDA7335 ELECTRICAL CHARACTERISTICS (V S = 8.5V; f = 1KHz; Rg = 600Ω; Tamb = 25°C; R11 = 43kΩ; all level referenced to -6dBm/400Hz, at D out with NR SW OFF; unless otherwise specified see application circuit of Fig. 1) NAB METAL position. SUPPLY Symbol Min. Typ. Max. VS Supply Voltage Parameter Test Condition 8 8.5 10.5 V IS Supply Current 11 18 26 mA V Vref Reference Voltage (pin 17) VDC DC Voltage pin 14 (R11 = 43K) SVR Ripple Rejection (Input referred) Vripple = 0.3Vrms fripple = 1KHz Mute Threshold Pin11 ON OFF MUTEth IMUTE MUTEA 4 4.3 4.6 1.15 1.25 1.35 80 85 90 95 Dolby OFF Dolby ON 10 Mute Attenuation V dB dB 0 2.0 Mute Current Unit 55 65 Min. Typ. 30 50 0.8 VS V V 20 µA dB Max. Unit PREAMPLIFIER Symbol Parameter RI Input Resistance II Input Bias Current GV Closed Loop Gain Test Condition (pin 2, 3, 28, 29) pin 4, 5 and 26, 27 shorted 32.5 70 KΩ 10 µA 35.5 38.5 dB 1 dB 5.8 7.25 KΩ ∆GV Closed Loop Gain Match -1 RM Resistance Metal Position 4.35 ∆R M Metal Resistance Matching -2 0 2 dB RN Resistance Normal Position 50 160 300 Ω eN Total Input Noise Unw. B = 20Hz to20KHz; Rg = 0Ω Rg = 600Ω A weighted; Rg =600Ω µV µV µV 0.45 0.8 0.5 RO Output Impedance (pin 6, 25) 1.7 KΩ F/Rl Reverse Low Level (pin 15) IN2 = ON; IN1 = OFF 0 0.8 V F/Rh Forward High Level (pin 15) IN2 = OFF; IN1 = ON 2 VS V EQl Normal Low Level (pin 30) 0 1.5 V EQh Metal High Level (pin 30) 3.5 VS V Typ. Max. Unit 5 mA 200 800 mV 1.1 1.4 KΩ 0.9 1.2 AUDIO MUSIC SENSOR Symbol Parameter IAMSOUT AMS Output Current VAMSOUT AMS Output Low Level R P21 Test Condition Min. IAMOUT = 2mA Input Impedance 0.8 AMSswl AMS OFF Low Level 0 0.8 V AMS swh AMS ON High Level 2 VS V VTH1 Interprogram Threshold Voltage (pin 9) VTH2 Interspace Threshold Voltage (pin 10) AMS th AMS Threshold Level see note (3) IAMSsw AMS Switch pin Current 1.2 1.45 1.7 V 4 4.3 4.6 V 0.6 1 1.4 V 5 10 15 µA DOLBY SECTION Symbol GV 6/20 Parameter Voltage Gain ∆GV Gain Matching RDI Dolby Input Res. Test Condition f = 1KHz; (pin 7, 24) DOLBY Min. Typ. Max. Unit OFF -1 0 1 dB OFF -0.5 46 0.5 63 dB KΩ TDA7335 ELECTRICAL CHARACTERISTICS (continued) DOLBY SECTION Symbol Parameter Test Condition RDO Dolby Output Impedance (pin 13, 18) S/H Signal Handling VS = 8V; THD = 1% DOLBY Min. Typ. Max. 100 200 300 12 13 OFF Unit Ω dB B DEC 1 Decode Out f = 10KHz; V I = 0.4dB ON -1.5 0 1.5 dB B DEC 2 Decode Out f = 500Hz; VI = -22.1dB ON -26.5 -25 -23.5 dB B DEC 3 Decode Out f = 2KHz; V I = -18dB ON -26.5 -25 -23.5 dB B DEC 4 Decode Out f = 5KHz; V I = -29.7dB ON -41.5 -40 -38.5 dB B DEC 5 Decode Out f = 10KHz; V I = -29.6dB ON -41.5 -40 -38.5 dB NRl Dolby ONLow Level Pin20 0 0.8 V NRh Dolby OFF High Level Pin 20 2 VS V GENERAL (PREAMPLIFIER + DOLBY) Symbol THD S/N CS Parameter Total Harmonic Dist. Signal to Noise Ratio Channel Separation Typ. Max. Unit VO = 0dB; f = 1KHz Dolby OFF Test Condition Min. 0.02 0.1 % VO = 0dB; f = 1KHz Dolby ON 0.05 0.1 VO = 0dB; f = 10KHz Dolby OFF 0.03 VO = 0dB; f = 10KHz Dolby ON 0.08 % Rg = 600Ω; VO = 0dB; Unweighted; Dolby OFF 63 dB Rg = 600Ω; VO = 0dB; Unweighted; Dolby ON 70 dB Rg = 600Ω; VO = 0dB; CCIR/ARM; Dolby OFF 54 63 dB Rg = 600Ω; VO = 0dB; CCIR/ARM; Dolby ON 56 72 dB Rg = 600Ω; f = 1KHz Dolby OFF 50 64 dB 70 dB 70 dB 75 dB Rg = 600Ω; f = 1KHz Dolby ON CT Channel Cross Talk % % Rg = 600Ω; f = 1KHz Dolby OFF Rg = 600Ω; f = 1KHz Dolby ON AUDIO MUSIC SENSOR (See Figure 2) Aim of this section is to detect interprogram spaces present on a recorded tape. Both the blanks (interprogram spaces) and the programs minimum detectable durations can be easily set by means of 2 external and independent time constants. Also the minimum detectable input signal level can be externally adjusted, by a dedicated gain network. Main blocks are: Variable gain limiter amplifier Signal detector circuitry Logic blocks able to avoid unproperoperations. Operations Description (refer to the simplified schematic of Figure 2). a)The two channels left and right mean signal coming from the preamp chain (AC coupled) are added (current) at the AMS input and pre- 56 sented to the limiter amplifier. The limiter amplifier gain is internally fixed to 40dB, and it could be reduced by the R8 external resistor. The AMSVth threshold is fixed at 1V. The following signal detector comparator informs of the presence of music signal (High level out) and avoids the erroneous detection of very low signal (like noise) as real program. b)The system moves in blank detection mode everytime the supply is turned on or, with power supplied, the AMS On/Off pin (to be driven by an open collector output) is turned off (T1 open). Once this condition has happened, the capacitor C 15 charges, defining a minimum reset time, long enough to reset the Flip-Flops FF1 and FF2 and to descharge the program detector external C7 capacitor. The charging current at the AMS SW pin is about 10µA. It follows that the reset time (C15 x Vpin8)/IC15 is given approximately by 0.122 x C15 ns where C15 is in µF. 7/20 TDA7335 c)From now on where the sum input signal (leftright) amplified by the limiter exceeds the signal detector threshold (3) the capacitor C7 is forced to charge. When the voltage across this capacitor reaches the comparator COMP1 threshold voltage Vth1 (approx. 2 Vbe) FF1 is set and FF2 is reset. (4) It follows that Q1 is turned on discharging the program detection capacitor (C7). The device is able to prevent false interspace detection and the end of the tape. (see Fig. 4). Note: (3): minimum RMS input signal is given by: Vin = AMSVth = 1K + R8 ⋅ 0.6 101K + R8 where Vin is the mean of left and right channels: d)Always when there is a recorded zone, Q1 is on; it becomes off only if a blank section is reached. When, with a time constant controlled by the R9, C9 network the voltage at space detection time pin reaches Vth2 threshold (comparator COMP2) a true blank section is detected and the FF2 is set. (The minimum charging time is approximately given by: 0.69 x C9 x R9 [sec] In this condition Q2 is ON, forcing the open collector AMS output to go LOW, informing the user that a true blank section has been detected. The state is then able to start from the above point c). Figures 3-4 show the signal behaviour. Vin = Vright + Vleft 2 (4): the charging current at pin 9 is about 20µA (half input signal) so program detection time constant is given by: C7 x 2Vbe = 70 x C7 [µF] = [msec] 20µA It is recommended to insert a resistor (R7) high enough to prevent fast C7 capacitor discharging. Figure 2: Audio Music Sensor AMS Gin RB 0.22µF C8 IN-L 1K 100K Rp21 R9 21 Vs 6 - + COMP1 NOR1 AMS th Vth0 Q1 Vs Vth1 Q Q FF1 S R POWER-ON RESET R S COMP2 8 10 AMS SW C15 R9 SPACE DETECTION TIME Vs 8/20 T2 INTS T1 23 Vth2 Q - Q2 FF2 + AMS OUT 22 R7 500K PROGRAM DETECTION TIME - LIMITER AMPLIFIER 25 INTP 0.1µF C7 SIGNAL DETECT. COMPARATOR + + IN-R 9 C9 D93AU098 TDA7335 Figure 3: AMS Timing Diagram Figure 4 9/20 TDA7335 ELECTRICAL COMPONENT DESCRIPTION (see figure 1) COMPONENT P R E A M P A M S D O L B Y RECOMMENDED VALUE TR1,TR2 C1, C2 C3, C4 R1, R2 R3, R5 R4, R6 1KΩ 1µF 10nF 1.2KΩ 6.8KΩ 300KΩ PURPOSE Left/Right Channel IN/OUT equalizer filter TR fixes the gain 150msec NORMAL 70µsec METAL C5, C6 0.33µF ±10% R8 C8 10kΩ 0.22µF R7 C7 470KΩ 0.1µF Set the interprogram detection time: INTP = 70 x 10-3 x C7[µF] = [sec] R9 C9 100KΩ 1µF Set the interspace detection time: INTS = 0.69 x C9 x R9 sec C15 0.1µF It fixes music search reset time; Tres = 0.122 x C15[µF] = [sec] if C15 expressed in µF Preamplifier out to Dolby B input coupling capacitor Define the AMS input threshold level Vin ⋅ 101K + R8 ⋅1.5 > 1V 1K + R8 where Vin = (Vright + Vleft)/2 C10, C11 0.68µF ±10% Dolby output coupling capacitors C12, C13 Dolby time constants C14 4.7µF ±10% 4.7µF R11 43KΩ It fixes the Iref current C16 R16 0.1µF 30KΩ If fixes the mute time (typ 10msec). Reference voltage external capacitor PINS DESCRIPTION: Internal Configuration Figure 5: PINS: 2 - 3 - 28 - 29 10/20 Figure 6: PINS: 7 - 24 TDA7335 PINS DESCRIPTION: Internal Configuration Figure 7: PINS: 13 - 18 Figure 8: PIN: 9 Figure 9: PINS: 4 - 27 Figure 10: PINS: 5 - 26 Figure 11: PINS: 6 - 25 Figure 12: PINS: 8 - 15 11/20 TDA7335 PINS DESCRIPTION: Internal Configuration Figure 13: PINS: 12 - 19 Figure 14: PIN: 14 Figure 15: PIN: 10 Figure 16: PIN: 22 Figure 17: PIN: 21 Figure 18: PIN: 30 12/20 TDA7335 PINS DESCRIPTION: Internal Configuration Figure 19: PIN: 20 - 11 Figure 20: PIN: 17 DEVICE CHARACTERISTICS Figure 21: Quiescent Current vs. Supply Voltage Figure 22: Quiescent Current vs. Temperature Figure 23: THD vs Supply Voltage Figure 24: THD vs Frequency 13/20 TDA7335 DEVICE CHARACTERISTICS (continued) Figure 25: THD vs. Output Signal Figure 26: THD + N vs. Frequency Figure 27: Channel Separation vs. Frequency Figure 28: Cross Talk vs. Frequency Figure 29: Ripple Rejection vs. Frequency Figure 30: Ripple Rejection vs. Frequency 14/20 TDA7335 DEVICE CHARACTERISTICS (continued) Figure 31: Ripple Rejection vs. Frequency Figure 32: Mute Attenuation vs. Frequency Figure 33: Mute Threshold Figure 34: Vref. & Iref. vs. Vsupply Figure 35: Vref. & Iref. vs. Temperature Figure 36: D.C. Voltage pin 14 vs. Vsupply 15/20 TDA7335 DEVICE CHARACTERISTICS (continued) Figure 37: Equalizer Threshold Figire 38: Forward/Reverse Threshold Figure 39: Noise Reduction Threshold Figure 40: Load Characteristcs Figure 41: Signal Handling vs. Vsupply Figure 42: Signal handling vs. Temperature 16/20 TDA7335 DEVICE CHARACTERISTICS (continued) Figure 43: AMS Threshold vs. Frequency Figure 44: AMS Threshold vs. Rex Figure 45: AMS Reset Time vs. Cex Figure 46: AMS Interprogram vs. C7 Figure 47: Interprogram Charging Current Figure 48: Interspace vs. C9 17/20 TDA7335 DEVICE CHARACTERISTICS (continued) Figure 50: Dolby-B Table Figure 49: NAB Network Normal Metal 18/20 TDA7335 mm DIM. MIN. inch TYP. MAX. A MIN. TYP. 5.08 MAX. 0.20 A1 0.51 A2 3.05 3.81 4.57 0.12 0.15 0.18 B 0.36 0.46 0.56 0.014 0.018 0.022 B1 0.76 0.99 1.40 0.030 0.039 0.055 C 0.20 0.25 0.36 0.008 0.01 0.014 D 27.43 27.94 28.45 1.08 1.10 1.12 E 10.16 10.41 11.05 0.400 0.410 0.435 E1 8.38 8.64 9.40 0.330 0.340 0.370 0.020 e 1.778 0.070 e1 10.16 0.400 L 2.54 M S 3.30 3.81 0.10 0°(min.), 15°(max.) 0.31 OUTLINE AND MECHANICAL DATA 0.13 0.15 SDIP30 (0.400”) 0.012 19/20 TDA7335 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 1999 STMicroelectronics – Printed in Italy – All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com 20/20