QS7785PF/CF 3D 2/4-Channel Stereo Surround Synthesizer NIPPON PRECISION CIRCUITS INC. OVERVIEW The QS7785PF/CF is an audio processor IC that generates 2, 4, 5-channel stereo surround signals from 2-channel stereo or mono sources using QSurround™ technology developed and licensed by QSound Labs, Inc. It can create 2-channel left and right surround effect signal for front speakers, and a rich enhanced surround signal using front speakers and surround speakers for 4-channel output. It also features a center signal output for clear listening of vocal and speech signals. FEATURES ■ ■ ■ ■ Surround signal output for 2-channel front speakers Surround signal output for 4-channel front + surround speakers Center speaker output for voice signals Parallel and 2 serial interfaces for mode control supported ■ • QS7785CF: I2C bus 2-wire serial interface (Data and Clock) • QS7785PF: 3-wire serial interface (Data, Clock and Strobe) 5 to 13V analog supply 4.5 to 5.5V digital supply 48-pin QFP package ■ Multimedia products ■ ■ APPLICATIONS ■ ■ TV, radio and VCRs Car audio PINOUT (Top view) QXBC4 FROUT FLOUT 25 CIN LPC MSC5 41 20 LPC 19 VREFIN MSC4 42 19 VREFIN 18 N.C. MSC3 43 18 N.C. 17 VREFOUT MSC2 44 17 VREFOUT 45 16 PSAVE MSC1 45 16 PSAVE QXCC1 46 15 MUTE QXCC1 46 15 MUTE QXCC2 47 14 BASS QXCC2 47 14 BASS QXCC3 48 13 SUR(SCL) QXCC3 48 13 SUR(SCL) 10 11 12 MONO AC BYP(SDA) 11 AC 9 10 MONO SP 9 SP(STRB) 8 8 P/S P/S 7 VDD 7 6 GND VDD 5 QXDC4 6 4 QXDC3 QS7785CF GND 3 QXDC2 12 2 BYP(SDA) 1 QXCC4 QXDC1 QS7785PF 5 MSC1 26 COUT 21 QXDC4 44 QXBC3 22 40 4 MSC2 27 39 MSC6 QXDC3 43 QXBC2 BASC2 3 MSC3 28 SLOUT QXDC2 42 QXBC1 SROUT 23 2 MSC4 29 24 38 1 20 VCC 37 QXCC4 41 30 RIN LIN QXDC1 MSC5 QXAC4 FROUT FLOUT 25 CIN 31 QXBC4 26 COUT 21 QXAC3 QXBC3 27 22 40 32 QXBC2 28 39 MSC6 QXAC2 QXBC1 29 BASC2 33 VCC 30 SLOUT QXAC1 QXAC4 31 SROUT 23 34 QXAC3 32 24 38 BASC1 QXAC2 33 37 35 QXAC1 34 RIN LIN 36 BASC1 35 QS7785CF 36 QS7785PF ORDERING INFORMATION Device Package QS7785PF 48-pin QFP QS7785CF 48-pin QFP I2C bus is a registered trademark of Philips Electronics N.V. Dolby and the double-D symbol are registered trademarks of Dolby Laboratories Licensing Corporation. NIPPON PRECISION CIRCUITS—1 QS7785PF/CF PACKAGE DIMENSIONS (Unit: mm) 0.35max 0.17 0.05 1.00typ 7.00 0.20 7.00 0.20 9.00 0.20 0.50 0.10 0.10 0.07 0.20 1.50 0.10 0 to 10 9.00 0.20 0.339typ 0.10 0.50 0.19 0.05 0.08 M 35 34 33 32 30 29 28 27 36 46 47 48 1 3 4 QXDC4 QXDC3 QXDC1 2 QXDC2 QXCC4 QXCC3 QXCC2 QXCC1 QXBC4 QXBC3 QXBC2 QXBC1 QXAC4 QXAC3 QXAC2 QXAC1 BLOCK DIAGRAM 5 BASC1 37 26 Front QEXPANDER 38 LIN MSC2 MSC1 VCC GND FLOUT SROUT SLOUT 43 44 21 To internal CIN 45 22 Multiplex/Decode/Level Shift 31 20 To internal COUT LPC Serial I/O VREFIN 23 42 FROUT 19 6 17 18 16 15 14 10 11 9 13 12 7 8 P/S MSC3 Surround QEXPANDER PSAVE MUTE BASS MONO AC SP(STRB) SUR(SCL) BYP(SDA) MSC4 41 N.C. MSC5 Mono to Stereo MSC6 24 40 VREFOUT BASC2 25 39 VDD RIN NIPPON PRECISION CIRCUITS—2 QS7785PF/CF PIN DESCRIPTION Name Number I/O Parallel Description Serial 1 QXCC4 O QEXPANDER C capacitor 4 2 QXDC1 I QEXPANDER D capacitor 1 3 QXDC2 O QEXPANDER D capacitor 2 4 QXDC3 I QEXPANDER D capacitor 3 5 QXDC4 O QEXPANDER D capacitor 4 6 GND – Ground 7 VDD – 4.5 to 5.5V digital supply 8 P/S I Input mode control (HIGH: parallel, LOW: serial) SP – I Enhancement control (HIGH: high spread, LOW: low spread) – STRB I Serial data strobe (not applicable to QS7785CF) 9 10 MONO I Mono-to-stereo convert select (HIGH: mono to stereo mode, LOW: normal mode) 11 AC I Center output control (HIGH: center on, LOW: center off) Bypass control (HIGH: bypass, LOW: Qsurround) BYP – I – SDA I/O SUR – I Surround speaker control (HIGH: surround speaker on, LOW: off) – SCL I Serial clock signal input 12 Serial data input (also serves as ACK signal output for I2C bus) 13 14 BASS I Bass boost mode control (HIGH: bass boost on, LOW: bass boost off) 15 MUTE I Mute signal control (HIGH: mute on, LOW: mute off) 16 PSAVE I Power save control (HIGH: power save on, LOW: power save off) 17 VREFOUT O VCC/2 reference voltage output 18 NC – No connection 19 VREFIN I VCC/2 reference voltage output (biased internally to VCC/2) 20 LPC I Center output lowpass filter 21 CIN I COUT output signal feedback input for front-channel output 22 COUT O Center signal output 23 SLOUT O Surround left-channel signal output 24 SROUT O Surround right-channel signal output 25 FLOUT O Front left-channel signal output 26 FROUT O Front right-channel signal output 27 QXBC4 O QEXPANDER B capacitor 4 28 QXBC3 I QEXPANDER B capacitor 3 29 QXBC2 O QEXPANDER B capacitor 2 30 QXBC1 I QEXPANDER B capacitor 1 31 VCC – 5 to 13V DC analog supply 32 QXAC4 O QEXPANDER A capacitor 4 33 QXAC3 I QEXPANDER A capacitor 3 34 QXAC2 O QEXPANDER A capacitor 2 35 QXAC1 I QEXPANDER A capacitor 1 36 BASC1 I Bass boost right-channel signal input NIPPON PRECISION CIRCUITS—3 QS7785PF/CF Name Number I/O Parallel Description Serial 37 RIN I Right-channel signal input 38 LIN I Left-channel signal input 39 BASC2 I Bass boost left-channel signal input 40 MSC6 I Mono/stereo conversion filter capacitor 6 41 MSC5 I Mono/stereo conversion filter capacitor 5 42 MSC4 I Mono/stereo conversion filter capacitor 4 43 MSC3 I Mono/stereo conversion filter capacitor 3 44 MSC2 I Mono/stereo conversion filter capacitor 2 45 MSC1 I Mono/stereo conversion filter capacitor 1 46 QXCC1 I QEXPANDER C capacitor 1 47 QXCC2 O QEXPANDER C capacitor 2 48 QXCC3 I QEXPANDER C capacitor 3 SPECIFICATIONS Absolute Maximum Ratings GND = 0V Parameter Symbol Rating Unit Supply voltage range (analog) VCC −0.3 to 15 V Supply voltage range (digital) VDD −0.3 to 7 V Input voltage range (analog) VIANA −0.3 to VCC + 0.3 V Input voltage range (digital) VIDIG −0.3 to VDD + 0.3 V VIOPEN 10 V Power dissipation PD 250 mW Storage temperature range Tstg −40 to 125 °C Symbol Rating Unit Supply voltage range (analog) VCC 5 to 13 V Supply voltage range (digital) VDD 4.5 to 5.5 V Operating temperature range Topr −20 to 85 °C I2C signal input voltage (SDA, SCL) Recommended Operating Conditions GND = 0V Parameter NIPPON PRECISION CIRCUITS—4 QS7785PF/CF DC Characteristics VCC = 9V, VDD = 5V, GND = 0V, Ta = 25°C Rating Parameter Analog input impedance Symbol Condition Unit min typ max ZAIN1 LIN, RIN 16 20 24 ZAIN2 CIN 8 10 12 kΩ Reference voltage output VREFOUT – VCC/2 – V HIGH-level input voltage VIH 0.7VDD – – V LOW-level input voltage VIL – – 0.3VDD V Input leakage current ILEAK Digital inputs, VDD input voltage −3 – 3 IILOPD SDA, SCL, 10V input voltage −3 – 3 ACK signal output from SDA, 3mA sink current 0 – 0.4 V µA LOW-level output voltage VOL Supply voltage (analog) VCC 5 – 13 V Supply voltage (digital) VDD 4.5 – 5.5 V Current consumption (analog) ICC – 6 8 mA Current consumption (digital) IDD – 0.3 0.5 mA ICCSAVE – 0.1 0.2 mA Standby current (analog) Noise and THD Characteristics VCC = 9V, VDD = 5V, GND = 0V, Ta = 25°C Rating Parameter Symbol Condition Unit min typ max Bypass noise voltage NBYP BYP = HIGH, SUR = MONO = SP = LOW, “A”-wgt, FLOUT, FROUT – 10 20 µVRMS Qsurround noise voltage (front) NQSF SUR = SP = HIGH, BYP = MONO = LOW, “A”-wgt, FLOUT, FROUT – 20 40 µVRMS Qsurround noise voltage (surround) NQSR SUR = SP = HIGH, BYP = MONO = LOW, “A”-wgt, SLOUT, SROUT – 15 30 µVRMS Bypass total harmonic distortion THDB BYP = SUR = HIGH, MONO = SP = LOW, LIN = RIN = 1VRMS, f = 1kHz, FLOUT, FROUT, SLOUT, SROUT – – 0.1 % Qsurround mono total harmonic distortion THDQM BYP = LOW, SUR = MONO = SP = HIGH, LIN = RIN = 1VRMS, f = 1kHz, FLOUT, FROUT, SLOUT, SROUT – – 0.1 % NIPPON PRECISION CIRCUITS—5 QS7785PF/CF AC Characteristics VCC = 9V, VDD = 5V, GND = 0V, Ta = 25°C Rating Parameter Symbol Condition Unit min typ max Bypass-mode maximum input voltage VB BYP = SUR = HIGH, MONO = SP = LOW, LIN = RIN, f = 1kHz 1.7 2.3 – VRMS Qsurround enhanced-mode maximum input voltage VQ+ BYP = MONO = SUR = LOW, SP = HIGH, LIN = RIN, f = 1kHz 1.8 2.4 – VRMS Qsurround-mode maximum input voltage (surround speakers on) VQS BYP = MONO = SP = LOW, SUR = HIGH, LIN = RIN, f = 1kHz 1.3 1.7 – VRMS Mono/stereo conversion enhanced mode maximum input voltage VM+ BYP = SUR = LOW, MONO = SP = HIGH, LIN = RIN, f = 1kHz 0.8 1.0 – VRMS Mono/stereo conversion mode maximum input voltage (surround speakers on) VMS BYP = SP = LOW, MONO = SUR = HIGH, LIN = RIN, f = 1kHz 0.8 1.0 – VRMS Bypass gain GBYP1 BYP = HIGH, MONO = SUR = SP = LOW, LIN to FLOUT, RIN to FROUT, f = 1kHz −2 0 2 dB Bypass gain (surround speakers on) GBYP2 BYP = SUR = HIGH, MONO = SP = LOW, LIN to SLOUT, RIN to SROUT, f = 1kHz −2 0 2 dB Qsurround mode gain GQ BYP = MONO = SUR = SP = LOW, LIN to FLOUT, RIN to FROUT, f = 1kHz 3.9 5.9 7.9 dB Qsurround mode crosstalk gain GQX BYP = MONO = SUR = SP = LOW, LIN to FROUT, RIN to FLOUT, f = 1kHz −1.5 0.5 2.5 dB Qsurround mode gain (surround) GQS BYP = MONO = SP = LOW, SUR = HIGH, LIN to SLOUT, RIN to SROUT, f = 1kHz −2.3 −0.3 1.7 dB Qsurround mode crosstalk gain (surround) GQXS BYP = MONO = SP = LOW, SUR = HIGH, LIN to SROUT, RIN to SLOUT, f = 1kHz −1.9 0.1 2.1 dB Qsurround enhanced mode gain GQ+ BYP = MONO = SUR = LOW, SP = HIGH, LIN to FLOUT, RIN to FROUT, f = 1kHz 4.7 6.7 8.7 dB Qsurround enhanced mode crosstalk gain GQX+ BYP = MONO = SUR = LOW, SP = HIGH, LIN to FROUT, RIN to FLOUT, f = 1kHz 1.3 3.3 5.3 dB Mono/stereo conversion mode leftchannel gain GML BYP = SUR = SP = LOW, MONO = HIGH, LIN = RIN, FLOUT, f = 1kHz 2.6 4.6 6.6 dB Mono/stereo conversion mode rightchannel gain GMR BYP = SUR = SP = LOW, MONO = HIGH, LIN = RIN, FROUT, f = 1kHz 3.6 5.6 7.6 dB Mono/stereo conversion enhanced mode left-channel gain GML+ BYP = SUR = LOW, MONO = SP = HIGH, LIN = RIN, FLOUT, f = 1kHz 2.4 4.4 6.4 dB Mono/stereo conversion enhanced mode right-channel gain GMR+ BYP = SUR = LOW, MONO = SP = HIGH, LIN = RIN, FROUT, f = 1kHz 3.3 5.3 7.3 dB Mono/stereo conversion mode surround left-channel gain GMSL BYP = SP = LOW, MONO = SUR = HIGH, LIN = RIN, SLOUT, f = 1kHz −3.8 −1.8 0.2 dB Mono/stereo conversion mode surround right-channel gain GMSR BYP = SP = LOW, MONO = SUR = HIGH, LIN = RIN, SROUT, f = 1kHz −1.6 0.4 2.4 dB SCL clock pulse period t0 QS7785PF 100 – – ns SCL clock HIGH-level pulsewidth t1 QS7785PF 40 – – ns SCL clock LOW-level pulsewidth t2 QS7785PF 40 – – ns SDA setup time t3 QS7785PF 15 – – ns SDA hold time t4 QS7785PF 30 – – ns STRB setup time t5 QS7785PF 50 – – ns STRB pulsewidth t6 QS7785PF 100 – – ns STRB hold time t7 QS7785PF 50 – – ns NIPPON PRECISION CIRCUITS—6 QS7785PF/CF Rating Parameter Symbol Condition Unit min typ max SCL hold time (I2C) tHD:STA QS7785CF 4.0 – – µs SCL setup time (I2C) tSU:STO QS7785CF 4.0 – – µs SDA hold time (I2C) tHD:DAT QS7785CF 5.0 – – µs SDA setup time (I2C) tSU:DAT QS7785CF 250 – – ns SCL clock HIGH-level pulsewidth (I2C) tHIGH QS7785CF 4.0 – – µs SCL clock LOW-level pulsewidth (I2C) tLOW QS7785CF 4.7 – – µs SCL rise time (I2C) tr QS7785CF – – 1000 ns SCL fall time (I2C) tf QS7785CF – – 300 ns Serial Interface Timing 3-wire (QS7785PF) timing SDA BYP SUR SP MONO AC BASS MUTE PSAVE SCL t3 t4 t1 t2 t6 t0 STRB t7 t5 Pin Description SDA Data signal. Sets mode settings. See “Operating Modes.” SCL Clock signal. Data is read on the rising edge. STRB Strobe signal. Mode switches occur on the rising edge of this signal. I2C 2-wire (QS7785CF) timing 2 I C address is {AD6 − AD0} = {1011011} SDA AD6 tHD:STA AD0 tr BYP tf SUR SP MONO tSU:DAT AC BASS MUTE PSAVE tSU:STO SCL tHIGH tLOW Pin tHD:DAT Description SDA Data signal. Sets slave address and mode settings. Address value, {1011011}, is shown in the figure above. See “Operating Modes.” SCL Clock signal. Data is read on the rising edge. NIPPON PRECISION CIRCUITS—7 QS7785PF/CF FUNCTIONAL DESCRIPTION Operating Modes The QS7785PF/CF operating mode can be controlled over either a parallel interface (P/S = HIGH) or one of two serial interfaces (P/S = LOW). The operating mode, control pins and SDA signal relationship is shown in the table below. Refer to “Serial Interface Timing” for the SDA signal format. Output mode Output signals1 Control pins/SDA signal No. Input signals BYP MONO SUR SP FROUT/FLOUT SROUT/SLOUT 0 0 0 0 Stereo Q – 0 0 0 1 Stereo Q+ – 3 0 0 1 0 Stereo Q Stereo Q1 4 0 0 1 1 Stereo Q+ Stereo Q1 5 0 1 0 0 Mono → Stereo Q – 0 1 0 1 Mono → Stereo Q+ – 7 0 1 1 0 Mono → Stereo Q Mono → Stereo Q1 8 0 1 1 1 Mono → Stereo Q+ Mono → Stereo Q1 9 1 0 0 × Stereo bypass – 1 0 1 × Stereo bypass Stereo bypass 1 1 0 × – Stereo bypass 1 1 1 × Stereo bypass Stereo Q1 1 2 Stereo only 6 Mono only 10 Stereo/Mono 11 12 Stereo only 1. – (dash) = no output signal. × = indicates don’t care. 1 = HIGH, 0 = LOW Output signal description Output signal Description Stereo Q Mixed front-channel Qsurround processed signal and input stereo signal output Stereo Q+ Same as Stereo Q with increased Qsurround signal component and reduced input stereo signal component. Stereo Q1 Mixed surround-channel Qsurround processed signal and input stereo signal output. Mono → Stereo Q Mono signal converted to virtual stereo signal, and then processed in the same way as Stereo Q signals. Mono → Stereo Q+ Mono signal converted to virtual stereo signal, and then processed in the same way as Stereo Q+ signals. Stereo bypass Input stereo signal is output as-is without processing. Mono signals should be input on both LIN and RIN. In output mode 1, the output signal is a mixed signal comprising the front-channel Qsurround processed signal and the input stereo signal, that is output on the 2-channel front speakers only. In output mode 2, the signal path is the same as in output mode 1, but the surround effect is enhanced by increasing the component of the Qsurround processed signal and reducing the component of the input stereo signal. In output modes 3 and 4, both the front speakers and surround speakers are used to form a 4-channel sys- tem for a rich surround space. The front-channel signal is the same as in output modes 1 and 2. The surround-channel signal is a mixed signal comprising an enhanced surround effect Qsurround processed signal and the input stereo signal. In output modes 5 to 8, the input signal is a mono signal. The mono signal is first converted to a virtual stereo signal and then processed in the same way as in output modes 1 to 4, respectively. In modes 5 and 6, the surround signal is output on 2-channel front speakers only. In modes 7 and 8, the surround signals are output on 4-channel front and surround speakers. NIPPON PRECISION CIRCUITS—8 QS7785PF/CF In output modes 9 to 11, the input stereo signal is output to the speakers without processing. The bypass function works for both stereo and mono input signals, and is used to listen to the original signals. In mode 9, the stereo signal is output on front speakers only. In mode 10, the stereo signal is output on both front and surround speakers. In mode 11, the stereo signal is output on surround speakers only. In output mode 12, the input stereo signal is output on front speakers, and a surround effect enhanced signal is output on the surround speakers. Center signal output Control pins/SDA signal1 Output signal BYP MONO SUR SP AC COUT × × × × 0 – × × × × 1 (RIN + LIN) / 2 1. – (dash) = no output signal. × = indicates don’t care. 1 = HIGH, 0 = LOW The center signal is output on COUT. See “Center Control.” Bass boost mode Control pins/SDA signal1 Output signal BYP MONO SUR SP AC BASS FROUT/FLOUT SROUT/SLOUT COUT × × × × × 0 Bass boost OFF Bass boost OFF Bass boost OFF × × × × × 1 Bass boost ON Bass boost ON Bass boost ON 1. × = indicates don’t care. 1 = HIGH, 0 = LOW The bass boost function is used to enhance the bass frequency component. See “Bass Boost.” Mute and power save Control pins/SDA signal1 Output signal BYP MONO SUR SP AC BASS MUTE PSAVE FROUT/FLOUT SROUT/SLOUT COUT × × × × × × 0 0 Available Available Available × × × × × × 1 0 – – – × × × × × × 1 1 – – – 1. – (dash) = no output signal. × = indicates don’t care. 1 = HIGH, 0 = LOW When PSAVE is HIGH, the analog stages of the device are turned OFF to save power. When MUTE is HIGH, all outputs are muted. NIPPON PRECISION CIRCUITS—9 QS7785PF/CF Speaker Arrangement The QS7785PF/CF supports the following speaker arrangements. 37 RIN SROUT 24 37 RIN SROUT 24 38 LIN FROUT 26 38 LIN FROUT 26 CIN 21 COUT 22 Front Speakers CIN 21 Rear Speakers COUT 22 FLOUT 25 FLOUT 25 SLOUT 23 SLOUT 23 Type A. Two front speakers in front and two surround speakers in rear Type B. Front speakers and surround speakers in front 37 RIN SROUT 24 37 RIN SROUT 24 38 LIN FROUT 26 38 LIN FROUT 26 CIN 21 CIN 21 COUT 22 COUT 22 FLOUT 25 FLOUT 25 SLOUT 23 SLOUT 23 Type C. Front speakers and surround speakers in front with actual center speaker Type D. Front speakers and surround speakers in front with center Type A Type C The front speakers are placed in front and the surround speakers are placed behind the audience to create a full rich enhanced space. Since the output signal for each channel has undergone Qsurround processing, the audio enhancement can be reduced to an adequate level even for television and similar signals where the left and right channels are located close to each other. A center speaker can be added in the center to reproduce vocal and speech signals for easy listening. The center signal is output on COUT. The signal is comprised of LIN and RIN signals, producing a sound image in the center. Type B The front speakers and surround speakers are both placed in front of the audience, perhaps because it is not possible to place speakers behind the audience. If the surround speakers are turned to face outwards, to spread the surround signal, the surround effect can be obtained. Type D If a center speaker is not available or not required, COUT can be connected to CIN using a resistor and the center signal is then added to the front-channel signal. The presence of the center signal added to the front channels reproduces the center signal sound image with virtually the same effect as that obtained using a center speaker. The connection using a resistor can be utilized for voice and similar fixed-band signals. See “Center Control” for a description of the method. NIPPON PRECISION CIRCUITS—10 QS7785PF/CF Center Control Adding to the front-channel output The center signal output on COUT is enabled when AC is HIGH. With this connection, the bass frequency components can be removed from a signal. Capacitors Ca and Cb and resistor Ra can be connected between CIN and COUT to form a highpass filter. The −3dB cutoff frequency of the filter is given by the following equation. This section describes the output function whereby fixed frequency sound sources, such as vocal and speech signals, can be output on the center signal. As mentioned for “Type C” and “Type D” speaker arrangements, the center signal can be output by direct connection to a speaker or by adding the signal to the front-channel output using a resistor connection between CIN and COUT. 1 f = ---------------------------------------2πCb ( Ra + R2 ) Using a center speaker The input signal on CIN is added equally to both front-channel outputs FLOUT and FROUT. Frequencies lower than voice tones are cut from the signal added to the front-channel outputs for clear reproduction of voice-band signals. When using a speaker, a capacitor Ca can be connected between LPC and COUT, forming a lowpass filter. The −3dB cutoff frequency of the filter is given by the following equation. 1 f = --------------------------2πCa × R1 Frequencies higher than voice tones are cut from the signal sent to the center speaker for clear reproduction of voice-band signals. VREFOUT Close when AC=H Open when AC=L Close when MUTE=H Open when MUTE=L LPC R1:20k 20 FROUT 26 R3:10k Ca Ra:10k CIN 21 Cb:0.082µF 22 COUT 10k 10k R2:10k Cnter Speaker 10k 10k Front Right Speaker FLOUT 25 Front Left Speaker Center output connection V(COUT)/V(RIN)@V(LIN)=0 Gain −6dB 3dB 3dB GC fL= 1 1 fH= 2πCb(Ra+R2) 2πCaR1 GC=20 log R3 ( Ra+R2 )−6dB V(FROUT) or V(FLOUT) fL fH Freq. Center output frequency response Note: Internal resistance value, R1 and R2, may vary ± 15%. NIPPON PRECISION CIRCUITS—11 QS7785PF/CF Bass Boost With a signal input connected to BASC1 and BASC2, a bass boost function can be implemented. When BASS is HIGH, resistors RA and RB and RIN /LIN + 37 RA=10k RB:10k capacitor C are connected to form a lowpass filter. The lowpass filter signal and the original signal (RIN, LIN) are combined to boost bass frequencies. R1:20k R2:20k To Internal 36 BASC1 /BASC2 C:0.15µF VREFOUT Close when BASS=H Open when BASS=L Bass boost connection (Gb = 6dB, fC = 300Hz) . Gain ( Gb=20 log 1+ Gb R1 RA+RB ) R1 RA+RB RA RB 2πC RA+RB 1+ fC= fL=fC 10 0dB fL fC fH Freq. − fH=fC 10 1 2 1 2 log 1+ ( ) ( ) R1 RA+RB 1+2 RA+RB R1 R1 RA+RB 1+2 RA+RB R1 log 1+ Bass boost frequency response NIPPON PRECISION CIRCUITS—12 QS7785PF/CF TYPICAL APPLICATIONS Parallel Interface 5 to 13V 0.01µF 0.01µF 10k 39 BASC2 1000pF FLOUT 25 LPC 20 42 MSC4 VREFIN 19 43 MSC3 N.C. 18 44 MSC2 VREFOUT 17 45 MSC1 PSAVE 16 8 P/S 7 VDD 6 GND 5 QXDC4 4 QXDC3 3 QXDC2 2 QXDC1 1 QXCC4 46 QXCC1 8200pF QXCC2 47 QXCC3 48 SLOUT 4.7µF 4.7µF 4.7µF 8200pF 15 14 10µF 10µF MUTE BASS 13 SUR(SCL) 0.012µF 41 MSC5 12 BYP(SDA) 0.082µF 23 SROUT CIN 21 11 AC 2700pF 40 MSC6 10 MONO 0.022µF 24 COUT 22 9 SP(STRB) 0.15µF 0.22µF FROUT 26 QXBC3 28 QXBC4 27 QXBC2 29 VCC 31 QXBC1 30 QXAC3 33 QXAC4 32 QXAC2 34 10k 37 LIN 38 10k 4.7µF Signal Out Signal In 4.7µF RIN 3300pF 3300pF 4.7µF BASC1 36 0.15µF 4.7µF QXAC1 35 10k 8200pF 8200pF 47k 5V A capacitor for decoupling should be connected between supply and ground. NIPPON PRECISION CIRCUITS—13 QS7785PF/CF Serial Interface QS7785PF 5 to 13V 0.01µF 0.01µF 10k 39 BASC2 40 MSC6 1000pF FLOUT 25 LPC 20 42 MSC4 VREFIN 19 43 MSC3 N.C. 18 44 MSC2 VREFOUT 17 45 MSC1 PSAVE 16 8 P/S 7 VDD 6 GND 5 QXDC4 4 QXDC3 3 QXDC2 2 QXDC1 8200pF QXCC2 47 QXCC3 48 1 QXCC4 46 QXCC1 11 AC 0.012µF 41 MSC5 10 MONO 2700pF 0.082µF 23 SROUT SLOUT 4.7µF 4.7µF 4.7µF CIN 21 9 SP(STRB) 0.022µF 24 COUT 22 12 BYP(SDA) 0.15µF 0.22µF FROUT 26 QXBC3 28 QXBC4 27 QXBC2 29 VCC 31 QXBC1 30 QXAC3 33 QXAC4 32 QXAC2 34 37 LIN 38 10k 10k 4.7µF Signal Out Signal In 4.7µF RIN BASC1 36 4.7µF 3300pF 3300pF 4.7µF 0.15µF QXAC1 35 10k 15 14 13 10µF 10µF MUTE BASS SUR(SCL) SCL 8200pF SDA STRB 8200pF 8200pF 5V QS7785PF 5 to 13V 0.01µF 0.01µF 10k 39 BASC2 0.022µF 2700pF 0.082µF 0.012µF 1000pF FLOUT 25 24 23 40 MSC6 LPC 20 42 MSC4 VREFIN 19 43 MSC3 N.C. 18 44 MSC2 VREFOUT 17 45 MSC1 PSAVE 16 11 AC 10 MONO 9 SP 8 P/S 7 VDD 6 GND 5 QXDC4 4 QXDC3 3 QXDC2 2 QXDC1 46 QXCC1 1 QXCC4 SLOUT 4.7µF 4.7µF 4.7µF CIN 21 41 MSC5 8200pF QXCC2 47 QXCC3 48 SROUT COUT 22 12 BYP(SDA) 0.15µF 0.22µF FROUT 26 QXBC4 27 QXBC3 28 QXBC2 29 VCC 31 QXBC1 30 QXAC4 32 QXAC3 33 10k 37 LIN 38 10k 4.7µF Signal Out Signal In 4.7µF RIN QXAC2 34 4.7µF 3300pF 3300pF 4.7µF BASC1 36 0.15µF QXAC1 35 10k 15 14 13 10µF 10µF MUTE BASS SUR(SCL) 8200pF SCL SDA 8200pF 8200pF 5V A capacitor for decoupling should be connected between supply and ground. NIPPON PRECISION CIRCUITS—14 QS7785PF/CF NIPPON PRECISION CIRCUITS INC. reserves the right to make changes to the products described in this data sheet in order to improve the design or performance and to supply the best possible products. Nippon Precision Circuits Inc. assumes no responsibility for the use of any circuits shown in this data sheet, conveys no license under any patent or other rights, and makes no claim that the circuits are free from patent infringement. Applications for any devices shown in this data sheet are for illustration only and Nippon Precision Circuits Inc. makes no claim or warranty that such applications will be suitable for the use specified without further testing or modification. The products described in this data sheet are not intended to use for the apparatus which influence human lives due to the failure or malfunction of the products. Customers are requested to comply with applicable laws and regulations in effect now and hereinafter, including compliance with export controls on the distribution or dissemination of the products. Customers shall not export, directly or indirectly, any products without first obtaining required licenses and approvals from appropriate government agencies. NIPPON PRECISION CIRCUITS INC. NIPPON PRECISION CIRCUITS INC. 4-3, Fukuzumi 2-chome Koto-ku, Tokyo 135-8430, Japan Telephone: +81-3-3642-6661 Facsimile: +81-3-3642-6698 http://www.npc.co.jp/ Email: [email protected] NC9818BE 2000.11 NIPPON PRECISION CIRCUITS—15