SC7312 4-CH OUTPUT STEREO AUDIO PROCESSOR WITH 4 STEREO INPUTS AND TONE/VOLUME CONTROL DESCRIPTION The SC7312 is a volume, tone (bass and treble), balance (left/ right) and fader(front/rear) processor for quality audio applications in car radio and Hi-Fi systems. Selectable input gain and external loudness function are provided. Control is accomplished by serial I2C bus microprocessor interface. The AC signal settings is obtained by resistor networks and switches combined with operational amplifiers. Due to the Used CMOS technology, low distortion, low noise and low DC stepping are obtained. SOP-32-375-1.27 FEATURES * Input multiplexer: --4 stereo inputs --Selectable input gain for optimal adaptation to different sources * Four speaker attenuators: --4 independent speakers control in 1.25dB steps for ORDERING INFORMATION Device SC7312S Package SOP-32-375-1.27 balance and fader facilities --Independent mute function * All functions programmable via serial I 2C Bus * Loudness function * Volume control in 1.25dB steps * Treble and bass control * Input and output for external equalizer or noise reduction system BLOCK DIAGRAM HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 1 of 13 SC7312 ABSOLUTE MAXIMUM RATINGS Characteristics Symbol Ratings Unit VS 10.2 V Operating Temperature Tamb -40 ~ +85 °C Storage Temperature Tstg -55 ~ +150 °C Supply Voltages QUICK REFERENCE DATA Characteristics Symbol Min. Typ. Max. Unit Vs 6 9 10 V Maximum Input Signal Handling VCL 2 Total Harmonic Distortion ,V=1Vrms, THD 0.01 Signal to Noise Ratio S/N 106 dB Channel Separation, f=1kHz Sc 103 dB Supply Voltage Vrms 0.1 % f=1kHz Volume Control, 1.25dB step -78.75 0 dB Bass and Treble Control, 2dB step -14 +14 dB Fader and Balance Control, 1.25dB -38.75 0 dB 0 11.25 dB step Input Gain, 3.75dB Step Mute Attenuation 100 dB ELECTRICAL CHARACTERISTICS (Refer to the test circuit) (Tamb=25°C, VS=9.0V, RL=10kΩ, RG=600Ω, all controls flat(G=0), f=1kHz,Unless otherwise specified) Characteristics Symbol Test conditions Min. Typ. Max. Unit 6 9 10.0 V 20.0 35.0 mA SUPPLY VOLTAGE Operating Supply Voltage VS Operating Supply Current IS Ripple Rejection of Supply Voltage SVR 60 80 35 50 dB INPUTS SELECTORS Input Resistance RII Input 1, 2, 3, 4 Clipping Level VCL 2 2.5 Vrms Input Separation (note 2) SIN 80 100 dB Output Load Resistance RL Pin 8, 21 70 4 kΩ Minimum Input Gain GIN(MIN) Maximum Input gain GIN(MAX) 11.25 dB Step Resolution GSTEP 3.75 dB G=11.25dB 2 µV Adjacent gain steps 4 G=18.75 to MUTE 4 Input Noise eIN DC Steps VDC -1 kΩ 0 1 20 dB mV mV (To be continued) HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 2 of 13 SC7312 (Continued) Characteristics Symbol Test conditions Min. Typ. Max. Unit RIV 20 33 50 kΩ Crange 70 75 80 dB Minimum Attenuation AV(min) -1 0 1 dB Maximum Attenuation AV(max) 70 75 80 dB ASTEP 0.5 1.25 1.75 dB -1.25 0 1.25 VOLUME CONTROL Input Resistance Control Range Step Resolution Attenuation Set Error EA Tracking Error ET DC Steps VDC AV=0 to –20dB AV=-20 to –60dB -3 Adjacent attenuation steps From 0dB to AV max 2 dB 2 dB 0 3 mV 0.5 7.5 mV SPEAKER ATTENUATORS Control Range Crange 35 37.5 40 dB Step Resolution SSTEP 0.5 1.25 1.75 dB 1.5 dB Attenuation Set Error Output Mute Attenuation DC Steps EA AMUTE VDC 80 100 dB Adjacent attenuation steps 0 3 mV From 0dB to MUTE 1 10 mV ±12 ±14 ±16 dB BASS CONTROL (note 1) Control Range GB Step Resolution BSTEP 1 2 3 dB RB 34 44 58 kΩ ±13 ±14 ±15 dB 1 2 3 dB 2 2.5 Internal Feedback Resistance Maximum boost/cut TREBLE CONTROL (note 1) Control Range Gt Step Resolution TSTEP Maximum boost/cut AUDIO OUTPUTS Clipping Level VOCL Output Load Resistance RL Output load Capacitance CL THD=0.3% Vrms 4 kΩ 10 nF Output Resistance ROUT 30 75 120 Ω DC Voltage Level VOUT 4.2 4.5 4.8 V GENERAL BW=20 ~20kHz,flat µV 2.5 output muted Output Noise eNO BW=20 ~20kHz,flat 5 15 µV All gains=0dB A curve, all gains =0 dB Signal to Noise Ratio S/N All gains=0dB; Vo=1Vrms 3 µV 106 dB (To be continued) HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 3 of 13 SC7312 (Continued) Characteristics Symbol Distortion d Channel Separation Left/right Test conditions Min. Typ. Max. Unit Av=0,VIN=10mV 0.01 0.1 % Av=-20dB, VIN=1Vrms 0.09 0.3 % Av=-20dB,VIN=0.3Vrms 0.04 % 103 dB Sc Total Tracking Error 80 AV=0 to –20 dB 0 1 dB AV=-20 to –60 dB 0 2 dB 1 V +5 µA 0.4 V BUS INPUTS Input Low Voltage VIL Input High Voltage VIH 3 Input Current IIN -5 Output Voltage SDA Acknowledge Vo V IO=1.6mA NOTES: (1) Bass and treble response see Figure 16. The center frequency and quality of the response behavior can be chosen by the external circuitry. A standard first order bass response can realized by a standard feedback network. (2) The selected input is grounded through the 2.2µF capacitor. PIN CONFIGURATIONS CREF 1 32 SCL VDD 2 31 SDA GND 3 30 DIG GND CODE 4 29 OUT LF L 5 28 OUT RF R 6 27 OUT LR IN(R) 7 26 OUT RR OUT(R) 8 LOUD R 9 BUS INPUTS TREBLE SC7312 R4 10 24 BIN(R) BASS 23 BOUT(L) R3 11 22 BIN(L) R2 12 21 OUT(L) R1 13 20 IN(L) NC 14 19 L1 LOUD L 15 18 L2 RIGHT INPUTS LEFT INPUTS — L4 16 HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn 25 BOUT(R) LEFT INPUTS 17 L3 REV:1.2 2004.08.03 Page 4 of 13 SC7312 HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn Loudness (dB) THD & Noise (%) Channel Separation (dB) THD (%) THD & Noise (%) Noise ( V) Noise ( V) Loudness (dB) Loudness (dB) TYPICAL CHARACTERISTICS PERFORMANCE REV:1.2 2004.08.03 Page 5 of 13 SC7312 TYPICAL CHARACTERISTICS PERFORMANCE (continued) Fig.10 Input Separation ( L1,L2,L3,L4) vs. Frequency Fig.11 Supply Voltage Rejection vs. Frequency 100 VIN=1Vrms AV=0dB All controls Flat 90 80 Output Clipping Level (v) 100 Channel Separation (dB) Channel Separation (dB) 110 Fig.12 Output Clipping Level vs. Supply Voltage 90 80 70 Vsvr=0.5Vrms All Input to GND AV=0dB All controls Flat 60 5.0 RL=10k f=1kHz THD=0.3% 4.0 3.0 2.0 70 1.0 2 10 3 10 4 10 1 10 2 10 3 10 4 10 4 6 8 10 12 Frequency (Hz) Frequency (Hz) Supply Voltage (V) Fig.13 Quiescent current vs. Supply Voltage Fig.14 Supply current vs. Temperature Fig.15 Bass resistance vs. Temperature 8.0 6.0 4.0 50 8.5 48 ) 9.0 Bass Resistance ( Quiescent Current (mA) Quiescent Current (mA) 1 10 8.0 Vs=9V 7.5 7.0 4 6 8 10 12 44 42 6.5 2.0 46 40 -60 -30 0 30 60 90 Temperature ( ) Supply Voltage (V) -60 -30 0 30 Temperature ( 60 90 ) Fig.16 Typical Tone Response (with the Ext components indicated the test circuit) 15 AV=0dB Tone Response (dB) 10 5 0 -5 -10 -15 1 10 2 10 3 10 4 10 Frequency (Hz) HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 6 of 13 SC7312 APPLICATION NOTES 1. I2C BUS INTERFACE Data transmission from microprocessor to the SC7312 and viceversa takes place through the 2 wires I 2C BUS interface, consisting of the two lines SDA and SCL(pull-up resistors to positive supply voltage must be connected). 2. DATA VALIDITY As shown in Figure 17, the data of the SDA line must be stable during the high period of the clock. The HIGH and LOW state of the dtat line can only change when the clock signal on the SCL line is LOW. Fig. 17 Data Validity on the I2C BUS 3. START AND STOP CONDITIONS As shown in Figure 18, a start condition is a HIGH to LOW transition of the SDA line while SCL is HIGH. The stop condition is a LOW to HIGH transition of the SDA line while SCL is HIGH. Fig. 18 Timing diagram of I2C BUS 4. BYTE FORMAT Every byte transferred on the SDA line must obtain 8 bits. Each byte must be followed by the an acknowledge bit. The MSB is transferred first. 5. ACKNOWLEDGE The master(microprocessor) puts a resistive HIGH level on the SDA line during the acknowledge clock pulse(see Figure 19). The peripheral(audioprocessor) that acknowledges has to pull-down(LOW) the SDA line during the acknowledge clock pulse, so that the SDA line is stable LOW during this clock pulse. The audioprocessor which has been addressed has to generate an acknowledge after the reception of each byte , otherwise the SDA line remain at the HIGH level during the ninth clock pulse time. In this case the master transmitter can generate the STOP information in order to abort the transfer. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 7 of 13 SC7312 Fig. 19 Acknowledge on the I2C BUS 6. Transmission without acknowledge Avoiding to detect the acknowledge of the audioprocessor, the microprocessor can use a simpler transmission: simply it waits one clock without checking the slave acknowledgig, and sends the new data. This approach of course is less protected from mis-working and decreases the noise immunity. SOFTWARE SPECIFICATION 1. Interface protocol The interface protocol comprises: • • A start conditions A chip address byte, containing the SC7312 address(the 8th bit of the bytes must be 0). The SC7312 must always acknowledge at the end of each transmitted byte. • • A sequence of data(N-bytes + acknowledge) A stop condition (P) 2. Chips address 1 (MSB) 0 0 0 1 0 0 0 (LSB) 3. Data bytes MSB LSB Function 0 0 B2 B1 B0 A2 A1 A0 Volume Control 1 1 0 B1 B0 A2 A1 A0 Speaker ATT LR 1 1 1 B1 B0 A2 A1 A0 Speaker ATT RR 1 0 0 B1 B0 A2 A1 A0 Speaker ATT LF 1 0 1 B1 B0 A2 A1 A0 Speaker ATT RF 0 1 0 G1 G0 S2 S1 S0 Audio switch 0 1 1 0 C3 C2 C1 C0 Bass control 0 1 1 1 C3 C2 C1 C0 Treble control Note: Ax=1.25dB steps;Bx=10dB steps;Cx=2dB steps;Gx=3.75dB steps HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 8 of 13 SC7312 DETAILED DESCRIPTION OF DATA BYTES 1. Volume MSB 0 0 0 0 B2 B1 B0 LSB Function A2 A1 A0 Volume 1.25dB steps 0 0 0 0 0 0 1 -1.25 0 1 0 -2.5 0 1 1 -3.75 1 0 0 -5 1 0 1 -6.25 1 1 0 -7.5 1 1 1 -8.75 A2 A1 A0 Volume 10dB steps B2 B1 B0 0 0 0 0 0 0 1 -10 0 1 0 -20 0 1 1 -30 1 0 0 -40 1 0 1 -50 1 1 0 -60 1 1 1 -70 For example, a volume of –45dB is given by: 00100100 2. speaker attenuators MSB LSB Function 1 0 0 B1 B0 A2 A1 A0 Speaker ATT LF 1 0 1 B1 B0 A2 A1 A0 Speaker ATT RF 1 1 0 B1 B0 A2 A1 A0 Speaker ATT LR 1 1 1 B1 B0 A2 A1 A0 Speaker ATT RR 0 0 0 0 0 0 1 -1.25 0 1 0 -2.5 0 1 1 -3.75 1 0 0 -5 1 0 1 -6.25 1 1 0 -7.5 1 1 1 -8.75 0 0 0 0 1 -10 1 0 -20 1 1 -30 1 1 1 1 1 MUTE For example, attenuation of 25dB on speaker RF is given by: 10110100 HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 9 of 13 SC7312 3.Audio switch MSB 0 1 0 G1 G0 S2 LSB Function S1 S0 Audio switch 0 0 Stereo 1 0 1 Stereo 2 1 0 Stereo 3 1 1 Stereo 4 0 Loudness ON 1 Loudness OFF 0 0 +11.25dB 0 1 +7.5dB 1 0 +3.75dB 1 1 0dB For example, to select the stereo 2 input with a gain of +7.5dB Loudness ON the 8bit string is: 01001001 4.Bass and treble MSB LSB Function 0 1 1 0 C3 C2 C1 C0 Bass 0 1 1 1 C3 C2 C1 C0 Terble 0 0 0 0 -14 0 0 0 1 -12 0 0 1 0 -10 0 0 1 1 -8 0 1 0 0 -6 0 1 0 1 -4 0 1 1 0 -2 0 1 1 1 0 1 1 1 1 0 1 1 1 0 2 1 1 0 1 4 1 1 0 0 6 1 0 1 1 8 1 0 1 0 10 1 0 0 1 12 1 0 0 0 14 C3=Sign For Example, bass at –10dB is obtained by the following 8bit string is: 01100010. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 10 of 13 SC7312 TEST AND TYPICAL APPLICATION CIRCUIT HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 11 of 13 SC7312 PACKAGE OUTLINE SOP-32-375-1.27 UNIT: mm 20.98±0.10 2.54MAX 0.15±0.05 1.27 0.40 0.25±0.05 19.05 HANDLING MOS DEVICES: Electrostatic charges can exist in many things. All of our MOS devices are internally protected against electrostatic discharge but they can be damaged if the following precautions are not taken: • Persons at a work bench should be earthed via a wrist strap. • Equipment cases should be earthed. • All tools used during assembly, including soldering tools and solder baths, must be earthed. • MOS devices should be packed for dispatch in antistatic/conductive containers. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.2 2004.08.03 Page 12 of 13